problem with the PCM after battery replacement

[MrDove]

I had the PCM on my 2001 PT Cruiser replaced in December. We had a really frigid period during January accompanied by some difficulty starting the car. We assumed that the difficulty was just from the cold. The car wouldn't start right away but if you put the key into the "on" position and left it for a while it would eventually start right up.

We woke up one morning to find the battery completely dead. There wasn't even power to the dash or the keyless entry. No power whatsoever. We jumpstarted the car and drove it down to have the battery replaced.

We still had some difficulty starting after replacing the battery. In addition to that there have been a few error codes that popped up on the Odometer and there have been some clicking and whirring sounds coming from the engine compartment while the motor is off but the key is in the "on" position.

Here's the part I'm not sure about
My mechanic just called to tell me that disconnecting the PCM from the battery when it was replaced caused the whole thing to reset. He wants to charge me $90 to re-flash the PCM.

I'm concerned for two main reasons. First, We obviously had some trouble before the battery was replaced. That was the reason that we replaced the battery in the first place. It is, however, entirely possible that the original problem was caused by a the battery (which was almost 8 years old).

Second, shouldn't a place like Sears know if they need to connect the PCM to an alternate power source when changing the battery? Or did the battery lose power enough for the PCM to reset before we actually took out the old battery.

Does this sound like something I should pay $90 out of my own pocket for or is Sears at fault for not changing the battery correctly?

I hope I can get a quick response on this as the car is down at the shop right now.

[Mean Green]

Your mechanic is very wrong. People disconnect the negative terminal all of the time to reset the pcm, especially after installing power mods. Besides, he can't reflash your pcm. Only Flight Systems can do that.

[CREWZIN]

The PCM learns the way you drive (driving habits) from the first time you/original owner took charge of the car. It learns if you like to drive fast or slow plus other things. The only thing that happens when you disconnect one or both leads from the battery is that it resets itself to the original "out of the factory" settings. So your mechanic was right on that point, it did reset when you replaced the battery, but no harm was done unless Sears did some stupid thing with the positive and negative terminals during the installation.

I'm pretty sure Mean Green is right about the dealer being the only one able to flash the computer ...if indeed it needs to be done.

What kind of codes did the computer throw? Trouble starting after the new battery was in could be numerous things. What about your plugs and wires. When was the last time they were changed.

[Cartman]

Actually, some mechanics have puchased the equipment to flash PCMs. all that is required then is to pay to download the flash updates from chryslers tech site. so the mechanic may indeed be able to reflash the PCM.

"The car wouldn't start right away but if you put the key into the "on" position and left it for a while it would eventually start right up." - sounds like a fuel issue to me. 2001-02 had problems with the fuel modules so it wouldnt be that far fetched.

[MX-5]

Originally Posted by Mean Green

he can't reflash your pcm. Only Flight Systems can do that.

Those of us with Chrysler DRB-III scanners and flash programming can certainly update the PCM.

The dealer isn't the only option if you have a high-tech repair shop in your area.

[CREWZIN]

Cartman, Mike, thanks for setting us right about other places being able to flash the computer. Learn something new everyday.

[PTAbbey]

Hello Everyone, This is my first posting but I have been visiting the board for a while. I've been having nothing but trouble wit my PT. 2005 PT Convertible, bought used with 32,000 miles. I love the car, rides awesome, looks great but nothing but trouble. It's been in the dealer for repairs many times in 4 months, lucky for me it's still under warranty. Here is the problem intermittent start. Everything works, power all through the car but it will not start, here is what has been replaced, battery, starter, cm-shaft sensor, ignition sensor, computer key chip, alarm system, key, computer flash and reset and finaly the main computer today. The mystery is that the car will not start it gets towed and once it arrive at the dealer as it comes down from the tower the car starts. Does any one have any ideas, hope, etc.

[CREWZIN]

Welcome to the forum Abbey,

Looks like they replaced just about everything. There was talk about the ignition switch giving problems. The actual part that holds the key and allows everything to start or did they do that with the parts you already mentioned (ignition sensor)?

[Mean Green]

Keep in mind that, at times, dealers are entirely clueless diagnosing a problem and they will also throw your money at it and replace everything in hopes of fixing it. If you are out of warranty I would suggest you find a capable independent shop. An independent shop is more likely to fix something the first time as they want your repeat business whereas a dealer could sometimes care less because of the volume of business they do. Now I'm not dissing every dealer as some are very good. Also, keep in mind that independent shops usually charge 1/3 to 1/2 of what the dealer will charge for the same service.

[plbell]

Was just wondering what the final outcome for you was. My PT is now in a parking lot awaiting a tow for the same symptoms yours had. Everyone thinks Im crazy when I say it will probably start when the tow truck shows up.