Absolutely stumped...need resolution

J

jclgodale3

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Folks, please give me some guidance on this. Daughters 06 SR5 V6 ac/heat blower motor started the dreaded squeal. Bought a new one. Removed the glove box and lowered the lower panel which holds the 4wd module and another module. Disconnected the 2 plugs to the 4wd module and 1 plug to the other module to move the panel out of the way. Easily replaced fan blower and checked it operation...perfect. Start reassembly and plug all three connectors back in...easily. No bent pins (checked) and reassembled the panel. Turn the truck on to check blower and my 4lo light is blinking and beeping and my traction control light, differential lock and check engine light are all on! WTF?
nothing changed and no indication before parking to replace fan motor! Unplugged and re-plugged the module. No change. Truck drives normally but all these lights and beeping? Did the "unhook the battery" gimick and replaced. No different. All lights still on and beeping!
HELP!
 
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jclgodale3 said:
Folks, please give me some guidance on this. Daughters 06 SR5 V6 ac/heat blower motor started the dreaded squeal. Bought a new one. Removed the glove box and lowered the lower panel which holds the 4wd module and another module. Disconnected the 2 plugs to the 4wd module and 1 plug to the other module to move the panel out of the way. Easily replaced fan blower and checked it operation...perfect. Start reassembly and plug all three connectors back in...easily. No bent pins (checked) and reassembled the panel. Turn the truck on to check blower and my 4lo light is blinking and beeping and my traction control light, differential lock and check engine light are all on! WTF?
nothing changed and no indication before parking to replace fan motor! Unplugged and re-plugged the module. No change. Truck drives normally but all these lights and beeping? Did the "unhook the battery" gimick and replaced. No different. All lights still on and beeping!
HELP!
Click to expand...

Can you run a scan? Shot in the dark here, but in that kick panel underneath the glovebox I think is the 4wd ecu. Maybe check that it’s connected, and connected properly?

Also I would check fuses
 
simple said:
Can you run a scan? Shot in the dark here, but in that kick panel underneath the glovebox I think is the 4wd ecu. Maybe check that it’s connected, and connected properly?

Also I would check fuses
Click to expand...
Yes, checked, double checked and triple checked. Disconnected the 4wd ECU (2 connectors) to move the panel out of the way. Reconnected them appropriately when putting back together (no bent pins, connectors slid in easily).
This started after the blower install. Everything else stayed the same. I'll check fuses tomorrow but not sure why it would blow one by just disconnecting and reconnecting the 4wd ECU
 
With ignition off/key out, pull the 20A 4WD fuse, disconnect the 4WD ECU connectors, wait 5 minutes or more, reconnect ECU and then put the fuse back in.

See if that works.
 
lightfreak said:
With ignition off/key out, pull the 20A 4WD fuse, disconnect the 4WD ECU connectors, wait 5 minutes or more, reconnect ECU and then put the fuse back in.

See if that works.
Click to expand...
Just tried...in the sequence you stated. (but left unplugged for 15 minutes)
Reconnected in that sequence...no dice. NADA. same lights and beeping.
Anyone else please???
 
Yeah, definitely pissed off the 4wd ECU so now it's in some kind of error mode. I thought for sure that reset would have done the trick.

Did you actually try shifting in/out of 4Hi or 4Lo and locking the diff?

When I was working on my actuator I had this condition a couple of times. First thing the system does when you turn the truck on is do a bunch of self checks. If it detects an error any any of the components (front diff, t-case actuator, switch, etc.) it throws it into this mode. Until you can correct the error condition it's going to go in circles and keep popping the codes.

Just a shot in the dark....check the pins on the 4wd ECU again. If you have some handy, smear a glob of dielectric grease on the pins/sockets.

Also....any ground connections you may have taken loose for the blower swap? I don't remember if the 4wd ECU and TPMS boxes had a separate ground running down into the kick panel or if all the connections were through the harness.
 
TowMeOut said:
Yeah, definitely pissed off the 4wd ECU so now it's in some kind of error mode. I thought for sure that reset would have done the trick.

Did you actually try shifting in/out of 4Hi or 4Lo and locking the diff?

When I was working on my actuator I had this condition a couple of times. First thing the system does when you turn the truck on is do a bunch of self checks. If it detects an error any any of the components (front diff, t-case actuator, switch, etc.) it throws it into this mode. Until you can correct the error condition it's going to go in circles and keep popping the codes.

Just a shot in the dark....check the pins on the 4wd ECU again. If you have some handy, smear a glob of dielectric grease on the pins/sockets.

Also....any ground connections you may have taken loose for the blower swap? I don't remember if the 4wd ECU and TPMS boxes had a separate ground running down into the kick panel or if all the connections were through the harness.
Click to expand...
I'll recheck the pins but confident they are all straight. Only other wire disconnected was the plug to the fan. (no ground wires etc) Just the fan and the plugs to the 4wd ECU.
 
Hmmm...last idea I've got. In trying to re-time my t-case actuator I got into this same error mode a few times. In order to "reset" the 4wd ECU, with the vehicle off (no keys in the ignition, etc.) unplug both connections and leave it for a few minutes. Then plug the connectors back into the 4wd ECU. Hopefully, next time you start the engine it will go through the self-check and find no errors.

I know this is kind of "duh" but be sure you didn't bump the dash switch out of 4-Hi or accidentally disconnect it in your dash disassembly. I saw another very similar thread a while back where a guy was installing a new head unit and did just that.
 
*UPDATE* Here's the codes that were not there before the simple unplugging and plugging back in the 4WD module. Nothing else was touched during the swap out of the fan motor.
P-2772 "Four wheel drive low switch circuit range/performance
U-0126 "lost communication with steering angle sensor module"
U-0124 "Lost communication with lateral acceleration sensor module"
U-0123 "Lost communication with yaw rate sensor module"
U-0073 "Control module communication Bus off"
C-1340 "open circuit in center diff lck signal"
C-1223 "Malfunction in antilock brake control system"
C-1201 "engine control system malfunction"

REALLY? All from unplugging two plugs on the 4WD module under the glove box and plugging it back in?
WTF?
 
Last edited:
jclgodale3 said:
All ears...can you share the proper steps? Thanks
Click to expand...

I don’t remember the exact steps because I read about it several months ago, but there are a few threads that walk you through the process if you do a quick search on here. I’d search “gen 4 zero point calibration” and you should find the instructions. I believe there are also vids on YouTube as well. Good luck!
 
well...no resolution. Had to unplug the 4wd module to get the 4lo light off and beeping stopped. all other lights still lit up. Guess I'll get another module and see if that works. Just dumbfounded that unplugging then re-plugging a module
can cause all of this headache. Still open to suggestions
 
jclgodale3 said:
*UPDATE* Here's the codes that were not there before the simple unplugging and plugging back in the 4WD module. Nothing else was touched during the swap out of the fan motor.
P-2772 "Four wheel drive low switch circuit range/performance
U-0126 "lost communication with steering angle sensor module"
U-0124 "Lost communication with lateral acceleration sensor module"
U-0123 "Lost communication with yaw rate sensor module"
U-0073 "Control module communication Bus off"
C-1340 "open circuit in center diff lck signal"
C-1223 "Malfunction in antilock brake control system"
C-1201 "engine control system malfunction"

REALLY? All from unplugging two plugs on the 4WD module under the glove box and plugging it back in?
WTF?
Click to expand...


I'm willing to bet you had the key on when unplugging or turned key on while it was unplugged. Pretty much the whole group of ECU'a run in a constant chain and you opened the chain while they were talking.

You can try pulling battery cables and touching them together as a last ditch effort idea. Remove negative at battery, remove positive at battery, hold the cables together NOT CONNECTED TO THE BATTERY for a few seconds. Theory here is to drain an residual voltage stored in any module. (Do this key off and out of ignition). It's like a hard reset for the whole system.

Otherwise, you're going to have to go thru each and every module via a good quality scan tool and clear every single code out of them. A code stored in one will be continued to be stored in all (because of the network) unless they all get cleared at once, hence the battery cable touching idea.

I had a forth Gen 4Runner in the shop a couple years ago and we unplugged the rear door/lift gate ECU and it set a whole bunch of codes. Didn't turn off until we went thru each computer and cleared them all. (ABS, airbag, Engine/transmission, 4wd, wipers) I forget but there was more even.
 
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