Buckaroo93
New member
Ok guys. I got the code read. C1234 - Malfunction in yaw rate sensor.
Where do I go from here? Not an expert but doesn't sound cheap or easy.
Where do I go from here? Not an expert but doesn't sound cheap or easy.
Check Engine, TRAC, AND/OR VSC On? Read Me!
- Thread starter BlackWorksInc
- Start date
catfishbirddog
New member
My 3 CEL/VSC/TRAC experiences
Just want to say thanks for all the posts on this subject in this thread and elsewhere, it's ridiculous that these will indicate about a billion different issues. These have all been covered many times over in various threads but here are the three problems and solutions I've experienced in my '05 4wd V8 Limited, ~150k miles:
CEL, VSC, & TRAC - This was years ago so I don't remember the code, but there was a CEL so there was a simple code to pull - in my case, loose gas cap (oops). It kept happening though, so I replaced the gas cap..fixed for good, $20. https://www.amazon.com/Genuine-Toyota-77300-33070-Fuel-Assembly/dp/B005CDNCQO/ref=sr_1_1?ie=UTF8&qid=1486513464&sr=8-1&keywords=gas+cap+toyota+4runner
CEL, VSC & TRAC - codes P1445, P2441 - the dreaded secondary air injection system. I ordered a bypass kit - there are more write-ups on this issue on Tundra forums. My valves were stuck closed so I just installed the electric bypass kit - it came with block-off plates and I will install those at some point but the electric bypass alone has worked fine for several months. There are cheaper options out there, but here's one: https://hewitt-tech.com/store/index.php?l=product_detail&p=7
VSC & TRAC, intermittent at first, then more often and eventually couldn't get the shifter out of Park without using a screwdriver on the bypass - This one is important! My brake light switch was failing! This is the little gray/white plastic receiver for a small wiring harness attached to the brake pedal. I caught it pretty quick but I was driving for at least a day with no brake lights, and of course the only indication at first was the stupid VSC/TRAC lights - eventually the locked shifter clued me in. It's a cheap Toyota part and I went even cheaper with this generic $24 one - https://www.amazon.com/gp/product/B00H3R9FTK/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
Again this is nothing new, just thought I'd share my 3 experiences specific to '05 V8 and thank y'all for helping me out each time.
Just want to say thanks for all the posts on this subject in this thread and elsewhere, it's ridiculous that these will indicate about a billion different issues. These have all been covered many times over in various threads but here are the three problems and solutions I've experienced in my '05 4wd V8 Limited, ~150k miles:
CEL, VSC, & TRAC - This was years ago so I don't remember the code, but there was a CEL so there was a simple code to pull - in my case, loose gas cap (oops). It kept happening though, so I replaced the gas cap..fixed for good, $20. https://www.amazon.com/Genuine-Toyota-77300-33070-Fuel-Assembly/dp/B005CDNCQO/ref=sr_1_1?ie=UTF8&qid=1486513464&sr=8-1&keywords=gas+cap+toyota+4runner
CEL, VSC & TRAC - codes P1445, P2441 - the dreaded secondary air injection system. I ordered a bypass kit - there are more write-ups on this issue on Tundra forums. My valves were stuck closed so I just installed the electric bypass kit - it came with block-off plates and I will install those at some point but the electric bypass alone has worked fine for several months. There are cheaper options out there, but here's one: https://hewitt-tech.com/store/index.php?l=product_detail&p=7
VSC & TRAC, intermittent at first, then more often and eventually couldn't get the shifter out of Park without using a screwdriver on the bypass - This one is important! My brake light switch was failing! This is the little gray/white plastic receiver for a small wiring harness attached to the brake pedal. I caught it pretty quick but I was driving for at least a day with no brake lights, and of course the only indication at first was the stupid VSC/TRAC lights - eventually the locked shifter clued me in. It's a cheap Toyota part and I went even cheaper with this generic $24 one - https://www.amazon.com/gp/product/B00H3R9FTK/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
Again this is nothing new, just thought I'd share my 3 experiences specific to '05 V8 and thank y'all for helping me out each time.
NeutronJon
New member
I just posted about this a few months ago. My front wheel bearing went and had enough slack that the speed sensor wasn't picking up correctly anymore. Gave me the VSC, TRAC, skid symbol, and ABS lights along with a blinking TPS light.
The sensor wasn't damaged and after the bearing was replaced everything cleared and I haven't had any problems since (about 9-10k miles ago, I do about 25k miles a year).
I recently went to get my state inspection (Texas) and failed for the P0441, P0446, P0455 codes. This was a surprise, since none of the VSC, Traction, CEL lights were illuminated.
Got the gas cap and wiped the computer by taking power off the battery overnight. Seems to have worked. But now I'm thinking the lights my not by working. When I start the car, no CEL light, no VSC, no Traction illuminate, even briefly (which they should).
Has anyone come across this? New and can't post a thread, searches all just pull up people with the gas cap issue/codes/lights.
Thanks.
04 4wd w/ 145000 if it makes a difference.
Got the gas cap and wiped the computer by taking power off the battery overnight. Seems to have worked. But now I'm thinking the lights my not by working. When I start the car, no CEL light, no VSC, no Traction illuminate, even briefly (which they should).
Has anyone come across this? New and can't post a thread, searches all just pull up people with the gas cap issue/codes/lights.
Thanks.
04 4wd w/ 145000 if it makes a difference.
justinsmnz
New member
Hi all - first post here and just want to thanks everyone for the awesome info and insight on the forum! I'm currently on my second 4Runner after recently trading my '05 SR5 V6 2wd to a local older gentleman for his '03 Limited V8 4wd (I'm moving to the NE from Florida next month and figured it would be best to get a southern-owned 4wd prior to the move.) The truck I'm working with now is the '03 with 201k on the clock.
Before the trade, the owner told me that the 4 lights (VSC TRAC, VSC OFF, ABS, and BRAKE) had come on a month or so prior after an independent shop replaced both front hubs. The shop did not give him a firm answer on what it could be, and he had not followed up since. Although the 4 lights have stayed illuminated the entire time I've had it, I have not seen a check engine light for any reason in the 2k miles I've put on the truck so far.
I replaced the front brakes (calipers, rotors, pads) prior to bringing it in to the dealership – not as a potential solution for the lights, but I figure I should mention it anyways. After swapping the brakes, I took the truck to the dealership for a dashboard swap and also had them flush and bleed the brake system while I was there. They pulled a code, but only wrote on the paperwork that it was a faulty front ABS sensor. I was in a hurry, and forgot to ask them for the actual code that it threw. Because of previous owner mentioned that the lights showed up after a hub replacement, my first thought was that a mech dropped one of the hubs and damaged a wiring harness on one side or another. When I got home, I ordered new harnesses for both sides and a pair of new speed sensors (OEM harnesses, 3rd party sensors)
All that to lead up to today: I replaced both front speed sensors and wiring harnesses. I disconnected the battery for an hour or so after installing, but before cranking, hoping that the new parts would clear out the codes on their own. Of course, it couldn't be that simple, and the lights stayed on like usual when I cranked it again.
I knew that there was a possibility that I would need to do a zero point calibration to get the codes to clear, so that was my next step. I parked in my garage, which is as flat as I can get around here, and did the calibration procedure. All went to plan, and everything seemed fine: the lights acted how they were supposed to (stayed on for 15sec then went off after clearing, then blinked while I reset, then stayed off when I turned off/on the third time.)
However, when I went to test drive after the zero point calibration, the VSC system engaged as soon as I hit the gas and before I could even get out of the driveway. I couldn't press the gas more than 10% or so before the VSC system engaged and lurched the car (in drive and reverse.) Of course, I couldn't drive it like that, so I shut it off and took the steps to clear the zero point calibration (touch paperclips 4 times then turn off.)
After clearing the calibration, the VSC TRAC and VSC OFF lights remained on after cranking, but the ABS and BRAKE lights remained off. The truck drives like normal again, but unfortunately after less than a quarter mile drive, the ABS and BRAKE lights came on again and have stayed on for several crank cycles.
Now I'm at a loss for my next step. I have an appointment with the dealership Thursday a.m. to pull the code again and have them do a zero point calibration in case I am screwing something up in the process, but besides that I'm not sure what other steps I need to be taking to clear out these lights.
Any thoughts or ideas would be greatly appreciated!
One more note: my driveway curves coming out of my garage, so I have to make a relatively sharp turn as soon as I back out. My driveway is also somewhat sloped to get out to the road. I don't know if either of those factors might be playing a part in the VSC system engaging immediately after the zero pt calibration.
Before the trade, the owner told me that the 4 lights (VSC TRAC, VSC OFF, ABS, and BRAKE) had come on a month or so prior after an independent shop replaced both front hubs. The shop did not give him a firm answer on what it could be, and he had not followed up since. Although the 4 lights have stayed illuminated the entire time I've had it, I have not seen a check engine light for any reason in the 2k miles I've put on the truck so far.
I replaced the front brakes (calipers, rotors, pads) prior to bringing it in to the dealership – not as a potential solution for the lights, but I figure I should mention it anyways. After swapping the brakes, I took the truck to the dealership for a dashboard swap and also had them flush and bleed the brake system while I was there. They pulled a code, but only wrote on the paperwork that it was a faulty front ABS sensor. I was in a hurry, and forgot to ask them for the actual code that it threw. Because of previous owner mentioned that the lights showed up after a hub replacement, my first thought was that a mech dropped one of the hubs and damaged a wiring harness on one side or another. When I got home, I ordered new harnesses for both sides and a pair of new speed sensors (OEM harnesses, 3rd party sensors)
All that to lead up to today: I replaced both front speed sensors and wiring harnesses. I disconnected the battery for an hour or so after installing, but before cranking, hoping that the new parts would clear out the codes on their own. Of course, it couldn't be that simple, and the lights stayed on like usual when I cranked it again.
I knew that there was a possibility that I would need to do a zero point calibration to get the codes to clear, so that was my next step. I parked in my garage, which is as flat as I can get around here, and did the calibration procedure. All went to plan, and everything seemed fine: the lights acted how they were supposed to (stayed on for 15sec then went off after clearing, then blinked while I reset, then stayed off when I turned off/on the third time.)
However, when I went to test drive after the zero point calibration, the VSC system engaged as soon as I hit the gas and before I could even get out of the driveway. I couldn't press the gas more than 10% or so before the VSC system engaged and lurched the car (in drive and reverse.) Of course, I couldn't drive it like that, so I shut it off and took the steps to clear the zero point calibration (touch paperclips 4 times then turn off.)
After clearing the calibration, the VSC TRAC and VSC OFF lights remained on after cranking, but the ABS and BRAKE lights remained off. The truck drives like normal again, but unfortunately after less than a quarter mile drive, the ABS and BRAKE lights came on again and have stayed on for several crank cycles.
Now I'm at a loss for my next step. I have an appointment with the dealership Thursday a.m. to pull the code again and have them do a zero point calibration in case I am screwing something up in the process, but besides that I'm not sure what other steps I need to be taking to clear out these lights.
Any thoughts or ideas would be greatly appreciated!
One more note: my driveway curves coming out of my garage, so I have to make a relatively sharp turn as soon as I back out. My driveway is also somewhat sloped to get out to the road. I don't know if either of those factors might be playing a part in the VSC system engaging immediately after the zero pt calibration.
Last edited:
justinsmnz
New member
Just wanted to follow up on this to let everyone know about my outcome.
On Thursday I took the truck to the dealership to have the code pulled and an "official" zero-pt calibration. After about 45 minutes the customer service rep came out to ask what specific parts I had replaced because the tech ran into the exact same issue I had following his computer calibration. However, he did confirm that it was the ABS system engaging during acceleration, and not the traction control system like I assumed. I told him that I replaced both front speed sensors and harnesses.
After he pulled back into the bay, he checked voltage on both sensors and got a zero reading. Because I had already replaced the sensors and harnesses, his thoughts were that it could only be two bad new sensors (less likely) or that the independent shop that replaced the hubs had either used the wrong bearings, or had installed the bearings backwards which caused the magnetic sensor marking to be ineffective (obviously more likely.)
After chatting with him, I decided that the hubs were the most likely cause, so I ordered two new bolt-on full assemblies (didn't feel like dealing with the pressure fit bearings.) They came in yesterday and I installed them this morning at the same time I installed a new CV axle on the front left due to a torn boot. After the install, I did another zero point calibration and about jumped for joy when I was able to make it out of the driveway and around the block without any hiccups.
I've put about 20 miles on it so far today and the lights have remained off! Obviously I won't know if I actually solved the issue for a few thousand more miles, but I'm being cautiously optimistic that it's been taken of.
The lesson for me has been:
A) Don't trust that the independent shops the previous owner used to have purchased the correct parts
B) Don't trust that the independent shops the previous owner used to have installed the parts correctly
C) Don't assume it's a goddamn brake switch or gas cap. :lol:
So, does anybody need a full set of [apparently] fully-functional front speed sensors and harnesses?
Last edited:
soula_ollie
New member
2004 4runner has the same problem, the check engine light came on and the VSC TRAC and VSC OFF are lit up.
The OBD reader gave back 4 codes:
1. C1201 - engine control system malfunction
2. C1241 - Low battery positive voltage or abnormal high battery positive charge
3. C1246 - Malfunction in master cylinder pressure sensor
4. P0420 - Catalytic efficiency below threshold bank 1
I have checked the gas cap...DIDN'T fix it. HOWEVER disconnecting the battery for 15 seconds are reconnecting turns the lights off (temporarily). Month later lights are back on. I am assuming the battery fix is temporary. Is there any way to know what the root problem could be?
The OBD reader gave back 4 codes:
1. C1201 - engine control system malfunction
2. C1241 - Low battery positive voltage or abnormal high battery positive charge
3. C1246 - Malfunction in master cylinder pressure sensor
4. P0420 - Catalytic efficiency below threshold bank 1
I have checked the gas cap...DIDN'T fix it. HOWEVER disconnecting the battery for 15 seconds are reconnecting turns the lights off (temporarily). Month later lights are back on. I am assuming the battery fix is temporary. Is there any way to know what the root problem could be?
The "quick fix" (disconnect battery for a few minutes) was implemented from another thread about these same diagnostic lights. Our 4Runner had been sitting for some time, and the last time that we recall driving it was to/from a vehicle inspection. Based on the other thread, this info prompted me to think that the issue is related to the inspection, and a connection to the ODBII connector by the tech. I now know that the "quick fix" (disconnect battery for a few minutes) is just to clear the codes. Oh well..if a real issue exists, it should trip the lights again, and I will get codes with my scanner.
It was good to find both of these threads in case these diagnostic lights stay on after startup again. The detailed explanations are appreciated.
The other thread url (Per a copy found by Google, TSB BR001-04 only applies to 2004-2005 4Runners. However, the folk(s) on the other thread suspect that newer model years may be impacted also.)
http://www.toyota-4runner.org/probl...ac-vsc-off-lights-zero-point-calibration.html
From the other thread
Cause: The code reader or other OBDII device has attempted to communicate with the 4Runner using the CAN protocol (involving pin #14) and this has caused the 4Runner to erase the "zero point calibration" numbers in its memory. Without these numbers it can't get accurate information from the yaw rate and deceleration sensors (in the center console near the gearshift) and so it disables traction and stability control functions.
The fix: Perform the "zero point calibration" procedure as described in TSB BR001-04. This procedure can be performed without special equipment such as a hand-held tester or OBDII reader. You only need the equivalent of a jumper wire to short together two pins of the OBDII connector at the right time and the right number of times between switching the 4Runner on and off. More detail is included below, leveraged from my other posts.
It was good to find both of these threads in case these diagnostic lights stay on after startup again. The detailed explanations are appreciated.
The other thread url (Per a copy found by Google, TSB BR001-04 only applies to 2004-2005 4Runners. However, the folk(s) on the other thread suspect that newer model years may be impacted also.)
http://www.toyota-4runner.org/probl...ac-vsc-off-lights-zero-point-calibration.html
From the other thread
Cause: The code reader or other OBDII device has attempted to communicate with the 4Runner using the CAN protocol (involving pin #14) and this has caused the 4Runner to erase the "zero point calibration" numbers in its memory. Without these numbers it can't get accurate information from the yaw rate and deceleration sensors (in the center console near the gearshift) and so it disables traction and stability control functions.
The fix: Perform the "zero point calibration" procedure as described in TSB BR001-04. This procedure can be performed without special equipment such as a hand-held tester or OBDII reader. You only need the equivalent of a jumper wire to short together two pins of the OBDII connector at the right time and the right number of times between switching the 4Runner on and off. More detail is included below, leveraged from my other posts.
ekywildcat
New member
I have 2004 V6 4-runner. Ck engine and VSC and other light came on. Engine doesn't run well. Had codes read, p0011, cam position A too adv, B1. Okay, I cleaned the vvt solenoid on the pass. side. Reset lights and truck ran great for about 10 mile then same thing. Any thoughts? Could vvt solenoid go bad after it warms up?
The Check Engine, TRAC, AND/OR VSC lights came back on; so I read the codes this time.
P0441 - Powertrain - Evaporative Emission Control System Incorrect Purge Flow
P0455 - Powertrain - Evaporative Emission Control System Leak Detected (gross leak, check fuel cap, piping etc)
- the codes read/reset with the Torque phone app and ODB2 scanner - $25
- a new Toyota OEM fuel cap delivered from Amazon - $21.31 (installed 4 days ago)
- no trip to dealership - priceless (well...overstated a bit, but it feels great to fix the issue myself, save several $, fix without a special trip for it, and justify the ODB2 & Torque app purchase more)
P0441 - Powertrain - Evaporative Emission Control System Incorrect Purge Flow
P0455 - Powertrain - Evaporative Emission Control System Leak Detected (gross leak, check fuel cap, piping etc)
- the codes read/reset with the Torque phone app and ODB2 scanner - $25
- a new Toyota OEM fuel cap delivered from Amazon - $21.31 (installed 4 days ago)
- no trip to dealership - priceless (well...overstated a bit, but it feels great to fix the issue myself, save several $, fix without a special trip for it, and justify the ODB2 & Torque app purchase more)
Last edited:
my VSC and TRAC lights came on after battery issues. I took it to get scanned for from and got a C1336 zero pt calibration code. Did the paperclip method and even though the lights didn't flash the same as previous examples, in the end they turned off. Glad I took it to confirm what I expected was the problem then spend $35 on a gas cap I didn't need.
Was wondering if youve had any success in straightening out your 4runner? Ihave an 04 v6 4x4. Same lights just lit up on mine pulled a p0430 code and parts store guy tells me to pull the sensor after the catalytic converter clean it and renstall. told me there is a sensor before and one after the converter that "communicate" with each other and its common for the downstream sensor to be fouled with carbon/exhaust soot causing miscommunication he says its either that or the converter itself may be shot. ive got 166,000 miles on this thing so it would seem to make sense, however this is my first 4runner and i have no prior experience with this manufacturer or model.
Supersonic
New member
Could someone please help me with the definition of "History" DTCs? Would "Enhanced" DTCs with no check engine light be same as "History" DTCs?
Some background;
The condition is no check engine light, no DTCs, but when menu for "Enhanced" DTCs is selected, the scan tool ask, Toyota? Reply, Yes. Then it gave 2 codes, p0300, p0125. I am never prompted as to these codes being "History", but I think they are.
I did more diagnostics at this point, and previous service history had shown the radiator and thermostat were replaced about 17,000 mile before, so I took out the coolant temperature sensor, tested it, failed test, so I replaced it.
While waiting for the mass air flow sensor to dry after cleaning it, I went to check codes with my scan tool (Innova 3160), well without the MAF plugged in I set 4 DTCs and now had 6 "Enhanced" DTCs and the check engine light came on.
Drive cycle - as defined as a cold engine to running temperature (184 to 186 degrees is what scan tool is reading). Correct if wrong?
After completing assembly and considering the circumstance, I let the check engine light cycle off on it's own, 2 or 3 drive cycles, though I'm not sure if I should be calling these drive cycles, I started and ran the engine 2 or 3 times and the check engine light went out, the DTCs cleared, though the 6 "Enhanced" DTCs are still present.
Next I thought I was waiting 40 drive cycle, for the computer to reset the "Enhanced" DTCs, but 2 of the second batch were gone today, maybe 20 drive cycles, but I still have the original 2 Enhanced p0300 and p0125, with p0102, p0113.
So I prefer to wait it out and see if the 40 drive cycles would allow the computer to reset showing no "Enhanced" DTCs. Am I on the right track?
I think I am because 2 are gone, but I expected it to be the original 2 to be gone. This could also be a computer programming issue, as in how a list is stored.
2 ways to store a list can be different, a 'Stack' first in, last out, or a 'Link' list of first in, first out. Could be that I am just seeing they used a stack for storing the "Enhanced" DTCs. The 4 new codes went in after the original codes, so they will be popped off the stack first, then the originals are later pooped off the bottom of the "Stack".
I wrote down the new "Enhanced" DTCs, if I can find that paper, I may be able to shed some light on how that "Enhanced" DTCs is stored. Probably not real important, but in some cases it may alleviate some anxiety.
EDIT: Found the codes, but won't help, must have cause a bad ground or something because the codes are not relate-able to present codes, c1223 Malfunction in ABS Control System (RX3), u0123 Lost Communication With Yaw Rate Sensor (YRS) Module, u0124 Lost Communication With Lateral Acceleration Sensor (LAS) Module, u0126 Lost Communication With Steering Angle Sensor (SAS) Module, B1152 Fuel Rail/System Pressure - Too High.
Last edited:
Supersonic
New member
Might have found relevant TSB, must go read it all but here is what seems relevant for me, though I don't know that I have a reset memory in Innova 3160 scan tool menu for enhanced obd2;
From; https://www.toyotaparts.metro-toyota.com/ECM_RESET_MEMORY_FUNCTION_TS-TC002-03.pdf
reset procedure 1
step b select ENHANCED OBD II,
step c select RESET MEMORY;
step d DO NOT USE THIS FUNCTION UNLESS INSTRUCTED BY REPAIR MANUAL. ONLY USE AFTER REPLACING THE ENGINE, AUTO TRANS, OR ECM ON CERTAIN VEHICLES.
step e EXECUTING THIS FUNCTION WILL RESET THE LEARNED VALUES IN THE ECM.
3. Start the engine and warm it up to normal operating temperatures before test–driving.
4. Perform a thorough test drive with several accelerations from a stop with “light
throttle” application until proper transmission shifting is verified.
From; https://www.toyotaparts.metro-toyota.com/ECM_RESET_MEMORY_FUNCTION_TS-TC002-03.pdf
reset procedure 1
step b select ENHANCED OBD II,
step c select RESET MEMORY;
step d DO NOT USE THIS FUNCTION UNLESS INSTRUCTED BY REPAIR MANUAL. ONLY USE AFTER REPLACING THE ENGINE, AUTO TRANS, OR ECM ON CERTAIN VEHICLES.
step e EXECUTING THIS FUNCTION WILL RESET THE LEARNED VALUES IN THE ECM.
3. Start the engine and warm it up to normal operating temperatures before test–driving.
4. Perform a thorough test drive with several accelerations from a stop with “light
throttle” application until proper transmission shifting is verified.
Supersonic
New member
Now that I paid a little more attention to the OBD2 scanner read out,
2 codes are Toyota Readiness, p0300 random misfire, and p0125 coolant temp too low.
2 others are Historical p0102, Mass or Volume Air Flow Circuit Low Input, p0113 Intake Air Temperature Circuit High Input.
So being I still have no check engine light on, my coolant temp at operational temperature has been steady 184 - 186 degrees, I was thinking it was normal and to wait for it to reset, but now I thinking change the thermostat and check the battery.
Looked up the manual for OBD2 scanner Innova 3160 and it shows options for
1. Current
2. Historical and
3.Readiness DTCs.
The actual scanner I am using is a Innova 3160d which automatically shows what type DTC is being displayed. I was not aware it was doing this for me, so scrolling between the codes I was reading the most relevant part and not observing this feature.
If I didn't learn the hard way I wouldn't remember...Now back to Toyota Readiness and the DTCs p0300 and p0125. I am going to deal with the coolant temp first bychecking the battery, then replace the thermostat and hope this also is causing the random misfire.
If not more diagnosis, but I've briefly checked the coils with a GTC 505 tool, it basically does a scope function, and pulled one spark plug, looked fairly new, gap was tight .045, NGK but not Iridium.
The Historical DTCs are likely going to cycle out, so that will be a lower priority for now.
2 codes are Toyota Readiness, p0300 random misfire, and p0125 coolant temp too low.
2 others are Historical p0102, Mass or Volume Air Flow Circuit Low Input, p0113 Intake Air Temperature Circuit High Input.
So being I still have no check engine light on, my coolant temp at operational temperature has been steady 184 - 186 degrees, I was thinking it was normal and to wait for it to reset, but now I thinking change the thermostat and check the battery.
Looked up the manual for OBD2 scanner Innova 3160 and it shows options for
1. Current
2. Historical and
3.Readiness DTCs.
The actual scanner I am using is a Innova 3160d which automatically shows what type DTC is being displayed. I was not aware it was doing this for me, so scrolling between the codes I was reading the most relevant part and not observing this feature.
If I didn't learn the hard way I wouldn't remember...Now back to Toyota Readiness and the DTCs p0300 and p0125. I am going to deal with the coolant temp first bychecking the battery, then replace the thermostat and hope this also is causing the random misfire.
If not more diagnosis, but I've briefly checked the coils with a GTC 505 tool, it basically does a scope function, and pulled one spark plug, looked fairly new, gap was tight .045, NGK but not Iridium.
The Historical DTCs are likely going to cycle out, so that will be a lower priority for now.
08 4runner mil
my mil light is on have codes p0456 c0205 c1201 c1223 the wheel sensor codes i think are there from when i had wheel bearings and breaks done i think not sure thats 1 question. the bearings n brakes were done about a year ago n no alarms
got gas the other day and a day or 2 later light came on will check gas cap as u recommended also can i get the codes reset to see what goes and what stays
So, this seems to be a constant source of confusion for many members as of late and since I have some time to kill, I figured I'd help clarify some things in an attempt to help members with this issue in the future.
On the 4th Generation 4Runners (this applies to a lot of Toyota SUVs, Minivans, and some cars as well) when an OBD-II DTC set and stored in the system, the MIL, TRAC, and VSC lights will always come on to indicate a fault in the OBDII System. If you have an ABS capable scantool you will see a DTC C1201-Engine Control System Malfunction, this DTC is always set when an OBDII DTC turns on the MIL; its the code that shuts off the VSC & TRAC systems and turns on the lights on the dash . Don't be worried about this DTC, when you correct the original DTC(s) that set the MIL on, the C1201 will erase along with the original codes with a scantool.
Before we delve into the how's and whys, lets first clarify some terminology;
MIL- The MIL or "Malfunction Indicator Lamp" is the SAE (Society of Automotive Engineers) term for the colloquially referred to "Check Engine Light (Sometimes abbreviated as "CEL") and is most often shown as a small engine block, sometimes "Check" is under the icon or in some other vehicles "Service Engine Soon" is used instead.
Examples of MIL Icons:
TRAC- TRAC is the abbreviation used by Toyota (and some other manufacturers) for Traction Control System. This is system is often used in combination with the VSC and ABS systems.
VSC- VSC is another acronym for Vehicle Stability Control and is often what you see when the vehicle is skidding/sliding as the vehicle tries to regain control; this is often in conjunction with the ABS and/or TRAC systems.
OBDII- This stands for OnBoard Diagnostics Generation II, this a standard of automotive self-diagnostic system(s) created in conjunction between SAE, EPA, and Vehicle Manufacturers. If you'd like to learn more about OBDII here's a helpful website; OBD-II - On-Board Diagnostic System
DLC- This is the 16 pin OBD-II mandated connector that all factory and aftermarket scantools communicate through and is mandated by OBD-II regulations to be mounted under the driver's side dash area. (On the 4the 4th generation 4Runner it is located underneath the access panel for the interior fuse block)
DTC- Another SAE term that stands for Diagnostic Trouble Code; these are designed to help aid diagnosis of a problem and identify a system that may have a problem, and example of a DTC would be a P0455- [Emissions, Gross Leak Detected] (A helpful break down of how to understand DTCs if you want OBD-II Codes Defined)
PCM- PowerTrain Control Module, the heart and brain of most modern vehicle's fuel injection, ignition, emissions, and sometimes transmission control systems. This puppy make your 4Runner go vroom vroom.
~
Now that we have some of the terminology explained, lets get into the two most common issues people run into:
MIL OFF, TRAC On, VSC On (and maybe ABS On IF an ABS code is set also)- There is a Non-OBDII Failure in the ABS/TRAC/VSC system and it requires an ABS Capable Scantool to pull accurate codes from, this is NOT an engine or emission related issue. Most Autoparts stores should have a capable scantool to get codes, but you may have to go to an independent shop and/or the dealer. An example of a failure of this type would be a speed sensor or failure in ABS wiring, ect. (Note that in 2003~2004 4th Gen 4Runners, low battery voltage and/or clearing DTCs can sometimes undo the ZPC (Zero Point Calibration) value stored in the ABS Module, this will result in the TRAC & VSC warning lamps turning back on despite having "fixed" your MIL condition.)
MIL is Blinking- This means there is a catalyst damaging misfire occurring (this is an OBDII mandated requirement and is present on all OBDII vehicles), you need to stop the vehicle and turn it off; failure to do so can result in permanent damage to your catalyst(s).
MIL On, TRAC On, and VSC ON- An OBDII failure has occurred in the vehicle that affects Engine Performance and/or Emission Control Systems and does not need a factory-capable scantool to pull codes (this means you can use a code reader from an autoparts store and get accurate codes) An example of this type of failure would be a Misfire, transmission issue, EVAP issue, ect.
Now I want to go into detail a little on the above mentioned OBDII failure because MANY people on almost EVERY forum there is incorrectly associate the MIL with a "Loose Gas Cap" and it gets repeated over and over and over again like some sort of magical "get out of jail" card...
An MIL on condition means there is an OBDII Failure Present in your vehicle that affects Engine Performance and/or Emission Controls and a DTC has been stored in the PCM. A loose gas cap COULD be the cause of the issue, but it more often than not is not even close.
Helpful Hint- If you have a P0455 DTC and ONLY a P0455 DTC stored in your pcm, then the gas cap MIGHT be the issue. A P0455 indicates that the EVAP Control System has found a leak over .040" and could not pass its monitor. This means you can replace the gas cap and still have the same DTC set if the leak was not the gas cap but somewhere else. Please also note that it can take a couple drive cycles to reset the MIL (without using a scantool) if the issue was in fact a loose gas cap, this often means anywhere from a day to a week or more depending on driving habits.
Helpful Hint- TSB 0030-10 indicates a prematurely failing gas cap as the cause for DTCs P0441, P0455, and/or P0456. The easiest way to rule the gas cap (this isn't 100% accurate, but works the majority of the time) is to tighten the gas cap until it "clicks", the gently unscrew it. If the cap has no resistance and unscrews it requires replacement, if the cap takes some effort to unscrew it's most likely good.
If you do have an MIL On condition, I highly recommend you go to a local autoparts store and have them pull and write down the DTCs stored in the vehicle before you post on the forum. The first thing we need to help you out with an MIL On condition is what codes are stored in the PCM; no one can do anything for you until we know what we're dealing with. This will save you the trouble of waiting on us to tell you to get the codes pulled and will help you get accurate information in a timely manner rather than taking days to get to any real significant assistance or direction.
I will also mention that some people may have scantools that indicate "Current" and/or "History" DTCs, these mean that the DTC was set by an issue that is occurring right now (Current) or that the issue has occurred in the past and the vehicle recorded the DTC for later review (History.) Typically only Current DTCs will set a warning lamp and History DTCs will simply show up when you do a health check; its important to know this distinction as you could pull up a History DTC for a problem and end up wasting time and effort trying to diagnose an issue that is not even present. Another type of DTC category you may see is "Pending", a Pending DTC is part of the "Two-Trip Logic" that OBDII dictates and some other modules use as well. Two Trip Logic means that the problem has to occur twice before the vehicle will set a "Current" DTC and turn on the MIL, a "Pending" DTC means that it has only happened once and the vehicle will not set an MIL on condition until it trips a second time and the DTC matures to a Current DTC (for example a P0420 or P0430 "Current" DTC means that the ECM ran the catalytic converter tests at two different times and returned two failure results, where as a Pending P0420 and/or P0430 means that the ECM ran the test and got a failure once and is waiting to see if it happens again before it sets the MIL and matures it to a Current DTC). Some modules such as SRS and ABS/VSC/TRAC do not use Two Trip Logic and will instead set a warning lamp on the first sign of an issue, these systems are "Single Trip Logic".
But if it makes you feel better you're more than welcome to tighten the gas cap and wait a few days to a week to see if the lights go away if you want, we'll still be here anyways.
Post Note-
I realized I never explained why the VSC & TRAC systems are disabled when an MIL is turned on. The simple answer is because Toyota is conservative and decided that since 9/10 the MIL is turned on for an OBDII DTC (which, except for a small handful of EVAP related DTCs directly impacts engine performance) that it meant the engine is not working as designed and cannot be trusted to work correctly with the VSC & TRAC systems when demanded (VSC & TRAC modulate ABS and Engine Output to bring the vehicle under control at times.) So the easiest and conservative solution is that when an OBDII DTC is set (i.e. an MIL is turned on,) they disable the VSC & TRAC systems because half the system has an issue. A lot of manufacturers have started to do this in the last decade as these vehicles get more and more complicated.
my mil light is on have codes p0456 c0205 c1201 c1223 the wheel sensor codes i think are there from when i had wheel bearings and breaks done i think not sure thats 1 question. the bearings n brakes were done about a year ago n no alarms
got gas the other day and a day or 2 later light came on will check gas cap as u recommended also can i get the codes reset to see what goes and what stays
Last edited:
Similar threads
