Can an original BCM be reflashed? I have been having an ongoing problem with loss communications with BCM and TCM.
Multiple warning lights. Starts with ABS, Traction control , ESC and then rpm , temp, fuel level , speedo and tach. Transmission then shifts harshly.
I have checked wiring harnesses for rub throughs, ground connections , fuse , battery voltage etc. It all seemed to start a year ago when oil sender failed and sent oil into
PCM. Engine runs fine, and everything works until the warning lights come on. It used to be about every couple of months and now it is every day. I am at my wits end with this.
To me, everything points to the BCM. Any help would be appreciated.

 

Just an update: I tested the battery voltage at the OBD2 port ( terminals 4 and 16) 12.21 volts . This is a 8 month old battery
Sam's Club Duracell. New alternator with 14+ volts running.

 

Your new battery is dead.

How could the BCM lose programming, yet still work sometimes?

The trans shifting is from the codes that you don't mention.

How do you know the loss of comm is between BCM and TCM. Did you use a VOM to trace the CANBUS?

If oil got up to the ECM then it could get up to the TCM.

 

I'm beginning to suspect the battery as the problem since seems to be degrading. I checked TCM and PCM connections and the PCM had the oil.
I checked the resistance on the CAN bus and it was in spec ( both resistor values). The codes I had were for loss communication of CAN BUS, loss communication to the PCM and TCM.
Since the weather is nasty today, I am going to replace the battery this week. I will check the voltage of the new battery. I was always a Diehard battery user, but they were not available at the time.

 

Get that one returned, low voltage is your issue, the battery might have a dead cell

 

Will do. And thanks for the feedback Old Blue!

 

Advance and CarQuest sell Diehard now, since Sears and K-Mart are gone.
What is the code you refer to? If there is a CANBUS comm problem it would show up in the resistor test. That means one of the modules is not getting enough juice.

 

You’re welcome, please keep us updated.

 

Replaced the battery today. "Old " one registered 12.1 volts. New registered 12.5 volts. Took a 20 minute ride and no issues.
Got in it 2 hours later, and soon as I backed out the driveway, The warning lights came on and all the gauges went nuts.
Checked codes. P2544 and U0073.
I'm stumped.

 

P2544, check the TCM and ECM connections Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

U0073

https://www.obd-codes.com/u0073