Limp Mode P2138

[Chilow]

Started my 2014 4Runner this morning and noticed the TRAC OFF light and check engine light was on. It was in limp mode. Pushing the gas pedal didn’t do anything.

I first thought rodents had chewed up the wires in the engine bay, but didn’t see any signs of it. I then used my OBD scanner and there was one code: P2138 (Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation). Tried to clear the code, but it wouldn’t work. I tried turning off my Pedal Commander and clearing the code - didn’t work. Finally, I unplugged the Pedal Commander and was able to clear the code. Started the 4Runner again and no more TRAC OFF or check engine lights. Drove it for about 50+ miles and no lights have come back on.

I know there were issues with other users using the Pedal Commander, but I’ve had mine installed since April 2018, so roughly a year and a half of usage and never had any issues. Why all of a sudden? I tried searching the forums, but didn’t see this same code associated with the Pedal Commander. Has anyone experienced this code or similar issues?

 

[borfoo3]

I removed mine after a similar incident a while back.. throttle body issue (can't remember the code)

 

[ElectroBoy]

Started my 2014 4Runner this morning and noticed the TRAC OFF light and check engine light was on. It was in limp mode. Pushing the gas pedal didn’t do anything.

I first thought rodents had chewed up the wires in the engine bay, but didn’t see any signs of it. I then used my OBD scanner and there was one code: P2138 (Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation). Tried to clear the code, but it wouldn’t work. I tried turning off my Pedal Commander and clearing the code - didn’t work. Finally, I unplugged the Pedal Commander and was able to clear the code. Started the 4Runner again and no more TRAC OFF or check engine lights. Drove it for about 50+ miles and no lights have come back on.

I know there were issues with other users using the Pedal Commander, but I’ve had mine installed since April 2018, so roughly a year and a half of usage and never had any issues. Why all of a sudden? I tried searching the forums, but didn’t see this same code associated with the Pedal Commander. Has anyone experienced this code or similar issues?

There are two signals coming out of the accelerator pedal position sensor which is simply a redundant transducer, or potentiometer, that outputs two voltage signals to the Engine Control Module. The ECM compares the two signals and if there’s any difference between them the ECM determines its a possible pedal problem and puts the vehicle into limp mode as a safety feature. Auto manufacturers don’t want a pedal failure causing uncontrollable wide open throttle. The Sprint Booster or Pedal Commander are electrical amplifiers which are supposed to maintain this redundancy although I’ve never seen any documentation that confirms that. They may simply have ganged the two outputs together. In any case, electronics do occasionally fail and one or both of the PC outputs could be hosed and the ECU caught it.

There have been several instances of these kind of failures in forum threads lately. Bad batch of parts, poor design, poor assembly, aging and part failure, who knows? There seem to be more PC failures than SB.

 

[slprciv]

Had my PC give me trouble with those CEL codes twice on the trails. Got rid of it. Had the SB on my Tacoma 2 months after I installed the PC on my 4runner and never had one issue. 2+ yrs later and my SB has been trouble free. Got a used SB for the 4runner, no issues yet either.

 

[Chilow]

Thanks for the replies so far. I have it unplugged for now and sent an email to Pedal Commander. Waiting to hear back from them before I plug it in again.

 

[Saker]

Thanks for the replies so far. I have it unplugged for now and sent an email to Pedal Commander. Waiting to hear back from them before I plug it in again.

Did your email say..... "I've switched over to "Sprint Booster", I want my $$$ back...... thank you for your time!" ?


:whip2:

 

[Chilow]

Did your email say..... "I've switched over to "Sprint Booster", I want my $$$ back...... thank you for your time!" ?


:whip2:

:lmao: it might come to switching over to Sprint Booster if there's no resolution to this. Cant stand the gas pedal in stock form.

 

[Chilow]

Quick update: Pedal Commander responded to my email and stated that I'm out of the 2-year warranty period, but I could ship it to them to run a diagnostic and repair if it is possible. I would just have to cover shipping costs both ways. If they find that it's unrepairable, it will be shipped back to me as is.

After driving 150 miles with the PC disconnected, none of the warning lights returned. I plugged the PC back in and have 10 miles on it so far without any of the warning lights so I'm hoping it remains that way. I'll continue to monitor and see where this goes.

 

[mcat707]

Quick update: Pedal Commander responded to my email and stated that I'm out of the 2-year warranty period, but I could ship it to them to run a diagnostic and repair if it is possible. I would just have to cover shipping costs both ways. If they find that it's unrepairable, it will be shipped back to me as is.

After driving 150 miles with the PC disconnected, none of the warning lights returned. I plugged the PC back in and have 10 miles on it so far without any of the warning lights so I'm hoping it remains that way. I'll continue to monitor and see where this goes.

All PC will say is, “everything checks out and looks good on this unit, sorry buddy, don’t know what to tell you”.

Then your out of pocket with shipping costs both ways. I think your gut feeling knows it’s the PC causing the issue. Why use it again? I personally wouldn’t.

 

[jp.vegas]

...Auto manufacturers don’t want a pedal failure causing uncontrollable wide open throttle. The Sprint Booster or Pedal Commander are electrical amplifiers which are supposed to maintain this redundancy although I’ve never seen any documentation that confirms that. They may simply have ganged the two outputs together.

Can you imagine the lawsuits if this failure mode caused the car to go to full throttle, plowing into a crowd like a Mustang leaving a car show?

This is one the main reasons I wouldn't install a device that works the way these do. While I'm OK entrusting Toyota with the software to run drive by wire, I'm not OK with a someone else who hasn't had to certify shit having that same ability.

 

[ElectroBoy]

Here are the Sprint Booster patents, from the US and Australia. They provide some interesting reading info and the schematic. These must be early generation patents; the cruise control function is not implemented in the SB version 3. At least it shows that it maintains the dual channels that the 4R ECU needs to do a health check of the accelerator pedal position sensor (gas pedal) plus SB combo.

US:
http://patft.uspto.gov/netacgi/nph-...8,706,373.PN.&OS=PN/8,706,373&RS=PN/8,706,373

Image:
Patent Images

Australian:
IP Australia: AusPat Disclaimer

 

[ElectroBoy]

Diagram from the Sprint Booster website. Here’s what the SB does to the outputs going to the ECU. Simple but effective.

BTW, the time scale on the horizontal axis is irrelevant, in fact it’s wrong. What it really shows is angle of the pedal vs voltage output.