We have a 2002 Jeep Grand Cherokee wit 82,000 miles on it. Always done the scheduled maintenance and has been a good vehicle for us.

So about six weeks ago after towing the boat my Malfunction Indicator Light came on. I did a little reading and I found out that sometimes very low gas mileage can cause the light to come on. So I let it go, it did not go off so I finally took it to the dealer. They said that my Powertrain Control Module has an error in it and needs to be replaced to a tune of about $600. Now, the truck runs perfectly. So I took it to a local guy that I was recommended to that deals in this type of stuff. He reset the code and sent me on my way, no charge. Well, later that afternoon the light came back on.

My local guy is honest and has not charged me for anything. He comes with a lot of recommendations. He can't replace the computer as a dealer MUST program the PCM...so he can't help me. But I asked him what would happen if I kept driving and not replacing the PCM. He said to go ahead...it could never get any worse. Especially because I have been driving around for six weeks already and no issues have come up at all.

So...if I am having no issues...would you still replace the PCM?

Do you have any emission requirements to meet in MI?

Not that I am aware of.

Did the dealer try to flash the PCM?

That an off-the-wall idea and I have no data or experience to back that up. CNY might say it's a dumb idea.

But, it may not be bad if the dealer tried to reinstall the PCM software.

WD, if the fuel mileage doesn't suffer horribly, the vehicle continues to run properly, doesn't blow tons of smoke out the tailpipe, and there are no emission concerns, you know I say to keep driving it. Now at $4/gallon, if the fuel economy is cut in half, you can do the math to figure out how many miles you would have to drive to waste $600.

How about getting a third opinion on it? My thought is after six weeks forget it. Put tape over the light and forget it.

WD,

What specific error code did the local guy get?

Also, here in Illinois, any "check engine" light is an automatic fail.

That's Chicago, Bonesian. Not Illinois. We don't have emissions testing in Illinois.

I too am curious what specific code they are getting. It sure would stink to replace that PCM, just to get a code for a dirty MAF sensor!

The "check engine" light is on in three of the four vehicles I own. All are problems that I've been told don't need to be fixed and therefore they won't get fixed.

The error code that is being detected is 601 which is just "internal Computer Error". The local guy said his machine showed "very rare" when it showed the code error. That is why he initially reset it and sent me on my way.

You can bet that I'm not gona tell ya to get a test light out.

No State reuirements to pass in Michigan.

If I recall, the Check Engine light will come on if there are (various) issues, and will go out if the issue does not repeat or someting like that over a course of time or miles or whatever.

Maybe some codes set and stay, I can't recall.

As a computer, my first thought is to reset it somehow. You'll probably have to read up, but it may be as simple as disconnecting the battery for a few hours, or more a complex procedure if the computer is powered by a backup source...

Might Google around for a similar issue experience, or a way to reset the computer to see if it goes and stays away.

Just a thought...

We had the equivalent light go on our car several times in the 7 years we owned it.

First time a sensor needing replacing.

Next time, it was a false malfunction.

Last time - about a month ago - a different sensor needed replacement. The dealer told us that our fuel mileage was suffering.

Funny thing - even before the light went on, the wife and I were wondering if someone was siphoning gas from our car as we noticed a drop in fuel mileage.

After the replacement, our fuel mileage seems better.

P0601 code info

Check in your owners manual warranty section and see what the specific warranty is on the PCM.
On GM products it is 8 years or 80,000 miles. I know that yours is slightly over that, but I also know they can do a "goodwill adjustment" to cover it.
After all, there is nothing you could have done to cause that failure and they should have no problem covering it.