QuestionQUESTION: Vehicle sporadically slows to 20 mph, electronic throttle and traction control warning lights illuminate. Transmission remains engaged and the vehicle must be shifted to neutral, turned off and restarted, and drives normally. Dealer could not identify codes, or issue, but replaced the pedal. Vehicle ran fine for a few weeks and now the problem has returned. Usually happens after driving 20-30 miles.
ANSWER: Hi James,
The electronic throttle control system is of course suspect. I will have to search this out in my '09 manual which is a bit time consuming because it doesn't have an index. I would believe that there is indeed a fault code stored in the powertrain control module that should be the basis of a repair because the warning light has been illuminated.
I would go back to the dealer and request that the problem be studied again and that you get credit for the previous repair costs. The pedal is actually an electrical unit and is not mechanically connected to the throttle body of the engine. I did find in the manual that when the pedal is replaced the mechanic should use a diagnostic readout box (DRB) so that the control module "learns" the characteristics of the new pedal so it will operate properly.
I would suggest that in addition to checking for a fault code that the mechanic do the relearn procedure again...as a first step. If something else is found to be the cause then definitely they should put back the original pedal and credit you for that false repair.
I would wonder if this problem would be covered under the manufacturer's warranty.
It may be relevant that the problem occurs after a period of operating time. This is characteristic of the failure of a solid state device which, as it heats up, begins to fail. That would point toward the throttle actuation electronic device on the throttle body proper as the place to consider as the site of this problem
I will study the manual and get back to you as soon as I find the detailed information. Look at your paperwork from the repair job and see whether there are any fault code numbers listed. If so let me know what they are, or if you get a numbers upon your return to the dealer.
Thanks for the rating, nomination, and kind remarks.
Roland
---------- FOLLOW-UP ----------
QUESTION: There were codes after all, from the bill:
"test drive had codes p0652 and p2127, inspected wiring and removed connectors from pcm inspected terminals, inspected wiring going to pedal monitored voltages graghed [sic} (assume it's graphed?) voltages replaced gas pedal retest drove 20 miles verified light stays off"
Does this help? Thanks!
AnswerHi James,
Except for no mention of the use of the DRB to "relearn electronic throttle control" (the characteristics of the new pedal's sensors) this would be what could be the response to the 2127. That code says that the #2 sensor on the pedal has a voltage reading that is too low. There is a chance that the code may be back again or a new code is present so that should be the first order of business at the dealer. Then do the "relearn" if the code is still 2127. The wiring connection of the pedal to the engine controller depends upon which engine and automatic trans (how many "speeds"?) you have. I have the wiring diagrams for the various possibilities if either you or the shop want to check that out. You might do well to discuss this with the shop manager and offer to drive it around until it starts doing the fault and bring it in at that time for immediate inspection.
So I will look for details about how the 2127 code should be handled and will let you know if and when I find that info.
Thanks for your rating and nomination. Feel free to do both again.
Roland
