VSC and TRAC Lights on No CEL No Codes

[Rock_Rat]

Interesting thing happened to me yesterday. I had the dash torn apart to run the wiring for my AEM gauge and to finally replace the amber LED bulbs I've had sitting around. No surprise I had to re-clock a couple of the bulbs to get them to work. This requires you to plug all the connectors in and then disconnect them all. All connectors are on one harness assy.

I also adjusted my coilovers so taking the rig out to settle the front end and re-adjust was also in order.

It didn't take long before the VSC and TRAC lights came on without a CEL or a code. I couldn't even make it out of my driveway. I turned the ignition off and started it again and the lights went away. As soon as I put it in reverse they came right back on. I did some research on the forum and came across a very interesting thread posted by [MENTION=126169]JohnTx12[/MENTION] back in June 2015. Trac Off and VSC Trac light on all of a sudden

What I find interesting about this thread is he was doing EXACTLY the same thing I was doing - replacing bulbs in the gauges with LED bulbs. So I read the entire thread and there was a lot of arm chair quarterbacking going on, all of which made no sense since there weren't any lights before beginning the LED swap.

Unfortunately, there was no closure on the thread. I don't know what the final fix was. However, in the same thread [MENTION=88616]Aelfwine[/MENTION] provided a link to UltimateYota on how to jumper your diagnostic port to pull ABS codes. http://www.ultimateyota.com/showthread.php?10048-Pulling-and-resetting-ABS-codes I know my third brake light needs to be re-clocked, so I'll start with the easy stuff first.

I'll keep everyone posted on what I find out but I'm sure both threads have some correlation to the LED lights and the wiring circuits. I believe the ABS computer is seeing an "open" somewhere in the lighting. There is an extremely remote possibility I moved or stressed a wire behind the center bezel as I neatly zip tied and "stuffed" all the AEM gauge wiring there in the space behind the ashtray.

 

[infamousRNR]

[MENTION=116467]Rock_Rat[/MENTION]

You know a similar thing happened to me...

I tried a ZERO POINT CALLIBRATION with no success but it's interesting you were working with bulbs...

Because I read a while back a member having these lights and it was because one of his shifter bulbs was out and my DRIVE light is out..

Not sure how they are correlated but make sure all bulbs are working.

I have yet to replace my DRIVE bulb to see if it fixes the issue

 

[Rock_Rat]

[MENTION=116467]Rock_Rat[/MENTION]

You know a similar thing happened to me...

I tried a ZERO POINT CALLIBRATION with no success but it's interesting you were working with bulbs...

Because I read a while back a member having these lights and it was because one of his shifter bulbs was out and my DRIVE light is out..

Not sure how they are correlated but make sure all bulbs are working.

I have yet to replace my DRIVE bulb to see if it fixes the issue

So I just went out and re-clocked my third brake light and it works but it didn't fix the VSC/TRAC lights.

I ran through the shifter since I also replaced those bulbs. All were clocked correctly except 2nd. Took the dash out and re-clocked that bulb and it works, however, I'm still getting the VSC/TRAC lights. No ABS light.

Hmmm wonder if I changed that one and it's in wrong. I didn't replace all the bulbs. My gut feeling tells me it has something to do with these LED's and Amp/Current draw to the computer.

IIRC the ABS computer needs to know when you're out of park and I think it's done some how through one of the two ribbons or the connectors coming off the PCB. I've got the wiring manual so I'll be looking at that later.

I'll go pull the codes from the diagnostic port and knock off all the simple stuff first.

EDIT: Also, replaced my flasher with a NOVITA EP35. I've been living with fast blinkers for quite some time. I have a practically brand new flasher in there that I just removed. Hated to do that.

 

[Rock_Rat]

Ok still no luck so far. I ran the jumper between TC and E1 and turned on the key. (BTW, I couldn't find a shorting plug anywhere as indicated in the Ultimateyota thread). Here's what I saw:

• ABS - Constant flash
• Cruise - Constant Flash
• VSC OFF - Nothing (not illuminated)
• VSC/TRAC - Flashed repeatedly as follows: 3 7 and 4 7.

 

[Rock_Rat]

The codes are as follows:

Neutral Safety Switch and Center diff. Again, I believe the ECU (EDIT: ABS Computer) is not seeing the voltage it is expecting to see because of the LED's.

EDIT: My plan is to change all the bulbs from P-L back to the original bulbs OR install a resistor. I'll go with the bulb change first.

 

[Rock_Rat]

Ok so having been wrenching for a "few" years there's two things I hate;

1. Losing a tool
2. Doing a job a second time

Well, here goes the second time. This time I'm replacing the LED bulbs with the original bulbs. Back to the bench I go. (I have sprinklers I need to fix and it's a beautiful day!)

I'm about 99% positive that there isn't enough voltage being seen coming off the PCB to the computer.

I've done all the easy stuff first. Checked power and grounds, checked wiring connectors, ran the DTC1 codes and did a zero point calibration.

Retraced my maintenance from yesterday which of course had to be the cause of the lights.

 

[Rock_Rat]

Fixed. So I ended up replacing the 74 LED Bulb - 3 SMD LED - Miniature Wedge Retrofit I got from Superbrightleds with the original bulbs and the VSC OFF and VSC TRAC lights no longer illuminate.

As suspected, those LED's in the instrument panel that I ordered do not provide the voltage the computer expects to see, thereby generating both of those codes.

I know others on here have replaced their entire instrument panel bulbs without any problems. It's important to note that not all LED's are the same.

So I decided to just keep the #24's installed instead. FWIW I only recommend replacing those 3 bulbs. This has been an interesting thread to myself I guess but I hope if someone runs across this problem in the future they don't start replacing O2 sensors, cleaning their MAF etc.

Few points to ponder;

• As suspected, the ABS computer saw an "open" circuit therefore generating the VSC OFF and VSC TRAC lights without a CEL or DTC code on the scan gauge
• The bulbs in the instrument panel for P through L provide more than just indication. They also provide the voltage through the bulbs to the ABS computer "closing" the circuit.

I hope this helps someone later on down the road.

Just re-trace your steps and do the easy stuff first. I'll add some of this in my build thread.

CLOSED.

Time to fix my sprinklers!!

 

[fourfive]

Glad you got it figured out. Respect your problem solving skills. I'm sure this will come in handy for me down the road.

 

[JohnTx12]

Never did fix it, thought about just pulling them out but haven't had the time. Glad you fixed it!

 

[Rock_Rat]

Never did fix it, thought about just pulling them out but haven't had the time. Glad you fixed it!

Unfortunately, in just one weekend I became a pro at removing and installing my instrument panel! Hopefully this brings closure to your problem. Be sure to update your thread when you finally fix it.

 

[Rock_Rat]

In case anyone was wondering about the sprinklers...hehe...broken pipe that feeds my 6000's. Capped it off! Now my other sprinklers are working!! yay! Successful day.

 

[fourfive]

In case anyone was wondering about the sprinklers...hehe...broken pipe that feeds my 6000's. Capped it off! Now my other sprinklers are working!! yay! Successful day.

Sounds like a productive weekend for you man.

 

[Rock_Rat]

Sounds like a productive weekend for you man.

Yes very productive! Finished up my carpet in the rig finally, changed out the bulbs, routed the wires for the AEM gauge, fixed my third brake light, changed out my flasher, routed my cell phone mic through the A-Pillar so i can use the hands-free option with the Pioneer HU and of course fixed the sprinklers! Whew. Headers go on tomorrow!!

Most productive was learning something about the VSC OFF and the VSC TRAC lights in regards to the instrument panel.

 

[LittleCaesar]

Good to hear. It is all about completing the circuit correctly.

I am impressed with the deduction but maybe more impressed with the size of that yard and the collection of Klein low voltage tools.

 

[infamousRNR]

Headers go on tomorrow!

Most productive was learning something about the VSC OFF and the VSC TRAC lights in regards to the instrument panel.

So please let us all know how the header install goes! I'm dreading attempting this on my own..

And why the heck would Toyota design something to where if a little bulb goes out your traction control is disabled?!? That's crazy

 

[Rock_Rat]

So please let us all know how the header install goes! I'm dreading attempting this on my own..

And why the heck would Toyota design something to where if a little bulb goes out your traction control is disabled?!? That's crazy

I decided against installing them after reading all the horror stories. I'm dropping it off at a high performance shop tomorrow at 7am. All I can do is take pictures of the install after its complete.

 

[Aelfwine]

I have to look into this. After doing my manual tranny swap my VSC TRAC are always disabled. I have looked through the wiring diagrams multiple times thinking I could fool the ECU to getTRAC to work, don't care about VSC really, even better if it stays off.

So basically my PNP switch is absent thus no lights on the dash except R. Maybe I was overthinking this and just need to rig it up somehow so that it thinks I'm in D when I'm driving and in P when I'm not. I know from the service manual that VSC shuts off if the speed sensors sense the movement and you're not in D or R.

 

[infamousRNR]

I decided against installing them after reading all the horror stories. I'm dropping it off at a high performance shop tomorrow at 7am. All I can do is take pictures of the install after its complete.

Would you be able to ask able any modifications or welding them had to do to make the fitment?...

Super curious about what the shop had to do outside of simply installing.

Like lifting the engine or something like that

 

[Rock_Rat]

I have to look into this. After doing my manual tranny swap my VSC TRAC are always disabled. I have looked through the wiring diagrams multiple times thinking I could fool the ECU to getTRAC to work, don't care about VSC really, even better if it stays off.

So basically my PNP switch is absent thus no lights on the dash except R. Maybe I was overthinking this and just need to rig it up somehow so that it thinks I'm in D when I'm driving and in P when I'm not. I know from the service manual that VSC shuts off if the speed sensors sense the movement and you're not in D or R.

Definitely a head scratcher. Seems anyone doing a manual swap on the newer 3rd gens with VSC/TRACwill run into the same situation. You'll probably need to wring out the wires and find out which one is going to the ABS comp. Running across the OP's thread and your info on the jumper helped me out tremendously yesterday. The fact the he got the same indications doing an LED swap pretty much solidified the steps I needed to take. I went back and looked at the WM after it was fixed to see how, or rather why toyota would tie in an instrument panel PCB to an ABS system. I'm sure I'm overlooking the obvious but I'm going to dig deeper into this. I hate not understanding. Keep me posted on what you find out.

 

[Rock_Rat]

Would you be able to ask able any modifications or welding them had to do to make the fitment?...

Super curious about what the shop had to do outside of simply installing.

Like lifting the engine or something like that

Yes absolutely. And you do need to lift the motor according to the TRD instructions. Basically raise it using the oil pan. I'll keep you posted.