Hello everyone my MC is giving me some problems as of late. At times she will not start and my mechanic have found these codes P1585: Inhibit circuit lamp control circuit. P1626: Anti-Theft system circuit, U1040: loss of EBCM communication, and U1064: loss BCM.


Has anyone had this issue before and what did you do to resolve it and how much did it cost?


Thanks in advance,
Marcell

 

I had those on my 04. The problem was the body ground, under the battery. Completely corroded, causing intermittent bad ground contact.

Worth a check.

 

I agree with panpan. Poor grounds are usually the culprit with this type of electrical problem. I also suggest checking the ground under the air intake duct on the stud bolt where two grounds are attached on the bolt connecting the transmission to the engine. Also check the one under the air filter box. You probably have a flashing security and battery light displayed in the dash when you turn the key on and attempt to start. You will most likely need to do a Security Re-learn Procedure after grounds are repaired.

Here's a link to the re-learn procedure: https://montecarloforum.com/forum/fw...rocedure-8598/

 

Thanks guys. After the car sat for an hour she fired up no problem. But I'm going to see my mechanic in the morning.

 

Hey guys. Just giving you an update. I took my MC to shop today and today she was throwing any codes like she was last week, but she still had difficulty starting twice today. I tried a security system re-learn and that did not work. I wonder if the viper alarm has something to do with it. Also while at a light she sounded as if she wanted to cut off but luckily she did not. My mechanic said since she's not throwing any codes today he does not know where to look and the battery ground wire is fine. Hopefully you all have more suggestions for me.


Thanks

 

if you're sure all of the grounds are good the next thing that I would check would be the ignition switch housing and/or the lock cylinder. the ignition switch housing acts as a conduit to relay information for the chip embedded in the lock cylinder to relay information through the class 2 serial data link to the BCM and PCM. it's hard to test either, and about all you can do is replace them and hope for the best.I would try the ignition switch housing first.if you replace the lock cylinder you will either have a different key for the doors and the ignition, or reset the tumblers for the old key. A security relearn procedure is definitely necessary after a lock cylinder replacement. Not sure, but I don't think it's necessary to do a security relearn procedure if you just replace the ignition switch.

 

The grounds are good. My mechanic had it for a week all the found was that the starter bolt was loose. It was tightened. For 3 days in row whenever she's driven for a while and the engine temp get too hot she doesn't want to start. I have to let the car sit anywhere from 20 minutes to over a hour with the hood up so it will start again. I do not know what is going on. Perhaps I should just take her to the dealer. She was throwing codes I have listed in my first post. But she's not throwing them anymore.

 

I assume the bolt that was loose was actually a nut that fastens one of the electrical wires to the starter? Hard to imagine one of the two bolts holding the starter to the block would cause no start symptoms without a grinding noise.
As for the overheating problem, could be any one of a number of problems...water pump, thermostat, clogged radiator, leaking head gasket etc...
Might be best to have a shop do some tests.
Thanks for the follow up, let us know how it turns out.

 

She's not over heating. The radiator is 5 years old. Water pump is nearly 3 years old. Thermostat is a year old. Had the valve cover and intake manifolds gaskets replaced a year ago. This morning I stopped to get gas and put air in my tire and she sat for over a hour and didn't start. Had her towed to the shop and she fired right up. I wonder if the bypass for the viper alarm is not telling the anti-theft system to disengage? I'm yltaking her to the dealer on Thursday so we will see. I want to keep my girl but this is getting annoying.

 

Another update on my MC. I dropped her off at the dealership last Thursday and they thought it was the ignition control module because it was not an OEM module. Turns out that's not the cause of the problem. So they're checking the wire harness which they say will be tedious. Also there is a recall on the MC Mine is a 2000. So the recall may be between 2000-2005 models. They changed the valve covers and something to do with the ignition switch. So go get that checked out if you haven't done so. Hopefully they will find out what is going on and I will let you all know.