about 6 mnths ago my check engine light came on reading P0601, but until about 1 mnth ago everything ran fine. It started with a little putter in the engine about once a week, then is gradually got worse. It almost feels like the trans is trying to shift just for a fraction of a second, but no change in speed or rpm. It usually gets alot worse when the engine is hot, the air conditioner is on, and I am accelerating. Then about 2 weeks ago it started making a small popping noise that sounds like its coming from under the hood. I dont think its a backfire cuz its not real loud and its definitely coming from the front of the truck, but it only does the pop when the putting is going on. Then to make things even more confusing, some days, for days at a time, it runs absolutely perfect. If anyone can give any advice I would greatly appriciate it!

 

Did you replace the PCM for the P0601 code, or did you blow the code out and hope for the best. If the engine runs bad, the transmission will have shifting problems too.Since you said the engne has been running bad, pull the codes out.

 

The P0601 Internal Control Module Memory Check Sum Error

I wonder if you just need a full tune up. What motor, trans, and year are we working on?

 

The P0601 Internal Control Module Memory Check Sum Error is an internal error in the memory module of the PCM, meaning it simply has bad memory. It may be possible to reflash the PCM but replacement is probably going to be needed.

 

I would do a full reset of the PCM first!

 

Yea, wouldn't hurt to try a reset. Probably would be a good idea to make sure all the connectors are clean and tight too.

 

First of all, sorry i fell off the face of the earth. Ive got a 1 month old son, been a little busy! Its a '99 5.9L 4x4. How do you RESET/REFLASH the PCM? Ive heard from others on the forum that if the PCM is bad, You'll know it, thetruck will not run!

 

Ive also been told that code (P0601) is an "Internal Controller Failure". Dont know if thats the same thing.

 

First of all, sorry i fell off the face of the earth. Ive got a 1 month old son, been a little busy! Its a '99 5.9L 4x4. How do you RESET/REFLASH the PCM? Ive heard from others on the forum that if the PCM is bad, You'll know it, thetruck will not run! Ive also been told that code (P0601) is an "Internal Controller Failure". Dont know if thats the same thing.

 

Look at my post here. RE: code p1391