This car was towed home with no throttle response where a machanic first tried a new accelerator pedal since it was a known issue and cost was about $120, this did not resolve the issue. He then went for the more expensive second half of the possible issue of a new throttle body which cost about $600, this fixed the car.

I was a quality engineer at GM, Oshawa and previously did quality, part design, testing & manufacture at Magna so I an fully qualified to perform failure analysis and wanted to see what failed. I removed the crimped cover on the TPS / electronic throttle control. I removed the main reduction gear and the failure was obvious, the 4 - 5 teeth on the gear that open the butterfly were gone. Now the tricky part, why did it fail? I do not have drawings, specifications, DVP&R, etc. so I am going to have to rely on my knowledge of plastics, Chrysler testing, gears and automotive knowledge. My biggest concern was the spring used to close the butterfly. I have worked on lots of carburetors and this spring was strong enough to pop the hood open, not the typical little coil return spring I have seen hundreds of times. I believe the gears were subjected to way more stress than typical for this application and I am going to hazard a guess of 10Lbs vs. 1Lb to actuate the butterfly. If I get a force gauge I can provide more accurate data. This would be my best guess as to the root cause of the failure.

The gears were not sheared or fractured, the high temperature nylon had gone mushy. I have worked on a dozen door lock actuators using these high tech nylons (many for Chrysler) and I have never seen gears fail with this melted appearance so I sent it over to one of my engineer associates.

The reduction gear that survived was PA66 PPS GF 40, the sector gear that failed was PPA GF30 + PTFE 15. The sector gear that failed was PPA GF30 + PTFE 15

An engineer replied with this comment

The sector gear that failed was PPA GF30 + PTFE 15

> I'm bewildered. I never heard of such a polymer. PPA is good, glass-filled makes it strong - but wtf is adding 15% Teflon. Teflon might be slippery but it is soft and it has a characteristic to cold-flow over time when pressed upon.

When you squeeze two PTFE insulated wires together with a cable tie you end up with an eventual short circuit. Not surprised the teeth disappeared off the gear eventually.

My final thought was how did this get past testing and onto vehicles so I kicked it around with my former Lab tech who favors Chrysler. We figure Chrysler or the throttle OEM tested this device over full travel over a million cycles, What they probably missed was 90% percent of the operation is done on those first few teeth, very rarely does anyone have their foot to the floor and use the top teeth. they probably should modify the test to place a higher number of cycles on the first few teeth? The DVP&R should be modified to capture this failure mode during testing?

This is my opinion with input from some smart associates. Collectively we have about 100 years automotive experience designing, testing, manufacturing and failure analysis, any other comments are welcome.

I know we had to test all our door lock actuators with similar technology for 3 times the expected life of the vehicle. We really think Chrysler should come to the party on this failure, these throttle bodies are not even performing for a half life.

Electromek

This experience haunts me to this very day. Every time I take a road trip I am terrified that this may happen again... I was driving an 8 hour trip and was halfway through. Unfortunately the time was after 12am. While driving through the middle of no where in the pitch black darkness at a speed of 70MPH, my car completely shuts off. I have no power, no lights to see the road, nor do I know where the shoulder of the road is on this small highway. I panic and pull over to what I think is the side of the road and call family. As I come to a stop by pulling the emergency brake since nothing else works, I begin to put the car in park. When I do this, the car immediately starts up and the engine is in acceleration without me putting my foot on the gas. I was excited with joy just to be able to possibly try and drive the car the rest of the trip (4 more hours) that I ignored the acceleration and put it and drive and made it the 4 hours. It was the most nerve wrecking drive I have ever experienced while the engine was sputtering and threatening to shut off at any moment and occasionally accelerating excessively without control. Once home, I had it towed to Dodge and they replaced the starter and recalled acceleration pedal..... REALLY??? This is truly insane and unacceptable for a company to build cars that TRY and kill you. Please, I beg you... Stay AWAY from this car.