Troubleshooting throttle pedal (signal implausible) code.

**S4James** · 04-19-2014 05:51 AM

Tripped this code the other day.. stone cold engine, hits 0 vacuum and car hits a wall. (accelerating in 1st.) 30 seconds later its fine.

well into the evening after 3 stops/restarts.. trips the ECS light, ABS and traction light on solid, no CEL

code pulled is the p1639 http://wiki.ross-tech.com/wiki/index...7/P1639/005689

Cleared and ran TBA.. did not return.. multiple TBA, stroking the TB postion up and down with the pedal... no code, nor any weirdness with block 60.

checked block 62.

3rd and 4rth values are supposed to be 2:1 ratio.

starting value:

14.7 7.3

ratio remains about right up to half throttle and starts to drift out of spec leading up to WOT

final numbers at WOT:

72.x 37.x

That being said the first and second values transposed themselves perfectly. So im not sure if the 2:1 ratio rule for #3 and #4 is a hard rule or just a guidline. Seeing as how the other two percentages were fine.

Ran the car next day and there were no issues. I suppose its possible that the TBA did the trick, but I have my doubts.

Suggestions or things to check would be appreciated.

**FlyboyS4** · 04-19-2014 06:19 AM

I had a throttle body go out. Most of the time the two potentiometer readings were properly related, but every so often one reading would go out of whack, causing the system to momentarily exceed spec and that would cause a fault code and throw the car into limp mode. It took a while of driving around logging the car continuously to capture a reading of this happening where I was able to see that the throttle body was the cause.

**S4James** · 04-19-2014 07:04 AM

Yeah im on my second TB. in my case it was sudden and total failure that left me on the side of the road. Couldnt even idle let alone limp home.

Im going to get a new TB (well, used) to have on hand asap just in case.

Are you suggesting the code im throwing is not related to the pedal assembly?

**dannyn424** · 04-19-2014 01:08 PM

Check brass pins on tb plug make sure they are all flush also map pedal tb signal they should inverse perfectly when you press pedal

**FlyboyS4** · 04-19-2014 01:26 PM

Originally Posted by S4James

Are you suggesting the code im throwing is not related to the pedal assembly?

No, just relating the issue I had involving the throttle and how it was identified.

**audacity** · 04-19-2014 04:32 PM

any o2 codes? bad o2s can cause pedal codes i know that seems odd but ross tech has a note on most of the pedal codes. also you should log to channels and they should work opposite of each other if not then the pedal is bad.