Thread: Strange Transmission issue

So I'm driving with my daughter in her 2001 gt. the trany kicks kinda hard and the rpms bottom out. no change in speed or acceleration. Just no RPMs on the readout. Any ideas would be helpfull as I am at a loss. Has 152000 miles and is possible the original trany.

So the RPM gauge just drops to zero and car still drives?

That can a crank sensor issue.

Sounds like you need a shift kit and new CPS.

cps lol pcs

agreed, sounds like a crank sensor

Just did my CPS same symptoms

Mine did the same thing. Never got it fixed though.

do the cps on these cars need to be timed or w/e?

Does the car start? If it does, it won't be the CPS.

I thought I had a bad CPS, but it didn't fix the problem. I am missing the 18x signal from the CPS, yet the the car starts and runs like a champ. Waiting for the rain and snow to stop falling so I can figure things out.

Chris that isn't necessarly 100% true. The crank sensors on these cars are very odd and fail reasonably often. I've seen things from an odd hiccup on the highway (technically car stalled and restarted itself quickly), to the car not starting, to the car stalling randomly and a few other issues. Most of the time you will not see a P0336 code for the crank sensor.

Technically there is a crank variation learn that can be done. However to get the car up and running, you don't need to time or adjust anything speciifcally.

There's a write up on it. Search on the words "Eas y crank" without the space in the first word and my screen name.

Originally Posted by hannon

@chris b. same kind of car. Got a buddy who was a mechanic for several years. Will run it by him and see what he thinks. I was hesitant about the cps. What you're describing sounds identical. Once, it happened when we first got it and the low trac and track off lights came on as well, but haven't seen that since.

If I could go back in time, I would test the CPS, but I can't. My buddy is a 20+ year Tech, but I have to pry him away from his 4x4 project to look at my ride. He says he will, but when. LOL

I will keep you posted when I figure it out.

Originally Posted by BillBoost37

Chris that isn't necessarly 100% true. The crank sensors on these cars are very odd and fail reasonably often. I've seen things from an odd hiccup on the highway (technically car stalled and restarted itself quickly), to the car not starting, to the car stalling randomly and a few other issues. Most of the time you will not see a P0336 code for the crank sensor.

Technically there is a crank variation learn that can be done. However to get the car up and running, you don't need to time or adjust anything speciifcally.

There's a write up on it. Search on the words "Eas y crank" without the space in the first word and my screen name.

85% correct? LOL I hear ya Bill. My scenario is this.....

Started the car one morning, no tach and "trac" light on. Checked the Aeroforce and had P0336. Did some research and my symptoms point to a bad CPS. Had tech buddy change it for me. Nothing changed and his super-dooper Snap-On scan tool wouldn't do a case relearn; not sure if this was his scan tool or the fact the P0336 was still there. I did a relearn with the Aeroforce, and nothing changed. And in all this, the car has always started, and runs fine. My MPG is down by about 1mpg or so (I do mostly highway driving), which is to be expected with the 18x signal being gone. Oh, and I have noticed extra pinging when the pedal gets near the metal, so I have been keeping said pedal away from said metal. LOL

From all the research I have compiled, the car won't start if it doesn't see both the 3x and 18x signal. I will have to chase the wiring to make sure all is well, but buddy is leaning towards either a bad ICM, or bad wiring between the ICM and PCM. The internet says the wiring can be an issue at the ICM and/or around the PCM at the A/C drier.

If anybody can shed any other light on this, it would be appreciated; might help the OP too.

I know my buddy can and will figure it out, but I would love to beat him to it.


PS: Bill, is this the thread you are referring too? http://www.grandprixforums.net/reluc...fun-56130.html

**UPDATE**

I swapped in a new ICM the other night and nothing changed.

Originally Posted by Bronco Boy

**UPDATE**

I swapped in a new ICM the other night and nothing changed.

Last night I was going to probe some wires to try and figure this out. As soon as I removed the plastic engine cover, it was obvious; a critter had been hanging out under there and chewed through the blue wire that connects the ICM and PCM. Easy fix for once.

Wait..you hadn't pulled the cover and looked at the basics?

Originally Posted by BillBoost37

Wait..you hadn't pulled the cover and looked at the basics?

Nope. Nothing like breaking rule #1. LOL

Fail.