Sudden Unintended acceleration

Jaambrose · **Joined:** Tue Oct 27, 2015 9:07 pm **Posts:** 4

I am new to this site and own a 2005 CRD with 227,000 miles on it. I looked for this topic and did not find it. I can assure you that this was not caused by large feet, heels, floor mats, turning around while backing up, or age.

3 weeks ago the car accelerated on its own while entering a highway after exiting another. I wrote it off that I perhaps resumed the cruise control. This week while traveling on a freeway at 70 mph with cruise control off, it accelerated and the throttle light( lightning bolt on left side of panel) came on. On the shoulder I cycled the key three times and it acceleration returned when I shifted it from Park to drive. During each cycle, the light cleared but reappeared. This also occurred when the tow truck operator thought about driving the car onto his ramp(bad idea). Keep in mind that it did not rev up in park.

At the repair shop as expected, it did not occur and no codes were read.

Has anyone had this occur and does anyone have suggestions as to cause?

flash7210 · **Posted:** Tue Oct 27, 2015 9:49 pm

I have never heard of such a thing happening.
But the throttle for this engine is completely electronic, so its not impossible.
Either the position sensor in accelerator pedal has gone bad or there is a short in the wiring somewhere.

mass-hole · **Posted:** Tue Oct 27, 2015 10:03 pm

flash7210 wrote:

I have never heard of such a thing happening.
But the throttle for this engine is completely electronic, so its not impossible.
Either the position sensor in accelerator pedal has gone bad or there is a short in the wiring somewhere.

Agreed, fueling is what controls the throttle, which is controlled by the ECU, so it has to be something between ur foot and the ECU which is like 3 feet.

Sent from my Nexus 6 using Tapatalk

geordi · **Posted:** Tue Oct 27, 2015 11:47 pm

The distance between zero throttle and moderate throttle is very short for the throw of your foot. The pivot is where all the magic happens. First thing I would try is buying a package of compressed springs from Home Depot and attaching one between the top of the pedal arm and a bit of frame under the dash, so that the pedal is pulled upwards whenever there is not a foot on it. This may sound silly, but it could be a weak pedal spring. If it solves the problem, replace the pedal assembly.

I believe IDparts sells the pedal assembly, not sure how much though, but the pack of springs is like $4.

olypopper · **Posted:** Wed Oct 28, 2015 3:13 am

My 06 5.9 cummins would continue to accelerate at times..........turned out to be an injector that would hang open. I was lucky that I was always able to keep it under control And it never scorched a piston.

papaindigo · **Posted:** Wed Oct 28, 2015 8:13 am

Check out viewtopic.php?f=98&t=76222 . If you have pressed the go pedal to merge or go up a trailer ramp and then backed off once proper speed is reached a "sticky" go pedal would cause acceleration to continue.

Brasher · **Joined:** Sat Mar 14, 2015 7:02 pm **Posts:** 80

I wouldn't think that an externally sticky throttle pedal (as in sticking at the pedal pivot) would cause the throttle light to trip. Admittedly I know nothing of the programming at the self check system, but I would assume that it can only be triggered by say, a sudden position change in the sensed throttle position (no matter how fast you "stomp on it", it will always ramp toward a position, assuming a fast cycle frequency), or an internal fault detected in the throttle actuator/stepper motor. My WAG for your issue would be the latter. Assuming the throttle actuator is a closed loop system, it would constantly compare actual throttle position against commanded position. If there were a discrepancy detected, it would trigger the light (assuming such a system exists :jester:

).

Regardless, this is a serious situation and shouldn't be taken lightly (and it seems that you aren't). It's one thing to unintentionally accelerate into a car, it is a completely different scenario to accelerate into a pedestrian or cyclist.

By the way, congratulations on achieving 227k miles. That is the highest CRD mileage I've ever heard of. I wonder if the other owners can add "throttle system malfunction" to the already long list of expected major repairs to these vehicles...

EDIT: Was the repair shop a dealer? If not, this is something you would want the dealer to check out. Page 8J-20 of the FSM states that "If the PCM sends a lamp-on message
after the bulb test, it indicates that the PCM has
detected an ETC system malfunction and/or that the
ETC system is inoperative. The PCM will store a
Diagnostic Trouble Code (DTC) for any malfunction it
detects."

dirtmover · **Posted:** Wed Oct 28, 2015 9:17 am

I've had my winter mats jamb between the side of the pedal and the carpet a couple of times but this doesn't sound like your issue.

You probably didn't think at the time but it might have been worth getting the tow truck operator to write a couple of sentences on the the tow receipt if he witnessed this behaviour. May be useful if the dealer continues to brush it off as no fault found and you end up in an accident at some point

This is clearly a safety concern You should file a report with the NHSTA. They probably won't follow up but at least it's documented in case this is the start of a pattern that more of us start to experience.

papaindigo · **Posted:** Wed Oct 28, 2015 9:25 am

Maybe not but checking for a sticky pedal takes like 30 seconds. Open drivers door, with engine off press pedal to floor by hand, remove hand. Does pedal immediately return to full up position or does it slowly return to up or only partially up position. If the former it's not sticky but if either of the latter it's sticky. I have no clue why the sticky perhaps just dirt/dust in the pivot point - what we did fixed the problem which has not returned.

To the OP if the CEL came on there should be stored codes even if the light went off and readers other than DCJ or equivalent may not read those stored codes. Just a thought

Jaambrose · **Joined:** Tue Oct 27, 2015 9:07 pm **Posts:** 4

Thanks for all the comments. We will check them out.

To clarify, the lamp that came on was "Electronic Throttle Control."

The only code read was P2299.

A Jeep dealer near the failure(Chicago) area looked at it first but I quickly lost confidence in them. My local Jeep dealer that has given me excellent service picked it up. I am in the tri-states area where Wisconsin, Illinois, and Iowa meet. There may have been codes but I could not get them from the original dealer. My local Jeep place has been driving the car to warm it up. Both incidents occurred after driving about 300 miles.

Keep in mind that the high throttle did not occur in Park but only when I shifted it to Drive. I did this 3 times and the tow truck driver did it once.

Next week I will be making loops for 3 hours on a fairly desolate section of 4 lane highway near my dealer to try to initiate a code. They drove it 45 minutes without a failure.

By the way, I may end up selling the car (on this site first), and I will fully disclose the unsolved issue.

John

geordi · **Posted:** Wed Oct 28, 2015 12:15 pm

Brasher wrote:

I wouldn't think that an externally sticky throttle pedal (as in sticking at the pedal pivot) would cause the throttle light to trip. Admittedly I know nothing of the programming at the self check system, but I would assume that it can only be triggered by say, a sudden position change in the sensed throttle position (no matter how fast you "stomp on it", it will always ramp toward a position, assuming a fast cycle frequency), or an internal fault detected in the throttle actuator/stepper motor. My WAG for your issue would be the latter. Assuming the throttle actuator is a closed loop system, it would constantly compare actual throttle position against commanded position. If there were a discrepancy detected, it would trigger the light (assuming such a system exists :jester:

).

There is no such thing as a "stepper motor" or "throttle" at all in this vehicle, you are thinking of a gas engine. The speed of the engine is ENTIRELY controlled by the computer and by the fuel injectors. Not a bad guess if this was a gas engine though.

The computer is obviously reading some form of an electronic fault, probably related to the pedal not reading zero at the same time that the brake is being depressed - that will definitely put the computer into a failsafe mode, but there are obviously other ways too.

Brasher · **Joined:** Sat Mar 14, 2015 7:02 pm **Posts:** 80

geordi wrote:

There is no such thing as a "stepper motor" or "throttle" at all in this vehicle, you are thinking of a gas engine. The speed of the engine is ENTIRELY controlled by the computer and by the fuel injectors. Not a bad guess if this was a gas engine though.

Derp. Good point!

Jaambrose · **Joined:** Tue Oct 27, 2015 9:07 pm **Posts:** 4

Thanks for all your help. I had the APPS changed. The garage drove it about 75 miles and no problems/no codes. Today I drove it for 200 miles and had no problems.

Sudden Unintended acceleration

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