Car trouble again, car won't start.
 

My 03 Nissan Maxima had oil problems in the past and I had to get my engine replaced due to knocking in the engine. Got the engine replaced, then two weeks later the car shut off while driving. Found out it was the body control module. Replace the BCM and drove it for 3 months, now car won't turn on. Battery is good. When i go to start the car the AC is blasting when i never turned it on. Also when i take the key out the dash lights (CEL, oil, Alarm, etc) remain lit for some time. Could it be the body control module again? If i change the BCM do i need to change the immobilizer as well?

Any help would be greatly appreciated!

Wow - have you got gremlins. Before you moved, you said that you needed a new engine harness. Did that get replaced with the engine?

I really don't know what to suggest except that the part about the dash lights make me wonder if they left one of the major ground wires off.

I know man, she doesn't love me! Engine harness was never changed. Only the thing that was fixed thatI was aware of was the body control module. Sad bro, I dunno what to do!

The dashlights just started today when the car didn't start.

did you get your car running? if so what was the problem? my 03 max has been on a stand still for a month now, cant find the issue. Today I checked for any codes and nothing.

Yes! It's absolutely the BCM again, all of the symptoms you've described are control via the BCM. However, don't rule out the highly possibility short-out at the ignition wiring harness. No, you do not need to change the immobilize transponder as it has nothing to do with the peripheral electrical devices.

Not yet, I just took out the starter to have it checked to see if it is the problem.

Great if it's the BCM again where am i supposed to find one? Where in the car is the BCM located? Is that something I can change out myself?

Also, where would i find the short-out at the ignition wiring harness? Thanks so much for your help!

Have you checked the fuses, especially the ones which provide power to ECU? Sounds like it doesn't have power.

I think, if you try to read the error codes this won't work either. If this is the case then the problem would be localized to the ECU, you can leave the rest of the car alone.

I changed the started cuz it neededto be changed. Didn't solve the problem. I will check the fuses tonight.

This is so disappointing!

Get the scanner, read the codes.

So I have found what I believe to be the problem! As x6runner stated it was related to be Body Control Module. I got a new flip key about 3 months ago and had it programmed and it worked fine until a month ago. It seems the key was the culprit. I got the car starting and then i would try to stop and start it again and it wouldn't start with the flip key. Then I unplugged the BCM plugged it back in and tried the OEM key and it worked. It has been working for the last week now with no problem. So it seems that the BCM with not likely the aftermarket key, what a shame, it was an awesome key.

Anyhow that was the problem and it might be solved now. Hope this helps anyone having the same troubles!

I don't think BCM is relevant. BTW, it is called Smart Entrance Control Unit or SECU in Maxima. Your key most likely the culprit if immobilizer can't read it every time.

In general, it helps if you make 1 change at a time but you unplugged / plugged SECU and also used OEM key at the same time making it hard to distinguish which one was causing the problem. Since SECU has nothing to do with starting the engine while the key is all about it I'd say it was the key.