I have a 2002 Z06 and know someone with a 2004 Z06. To troubleshoot, is there any harm in swapping out the BCM from his car into mine? I don't know of any different options between the two cars.

I just don't want to multiply my problems if putting his BCM in my car will alter it in any way and cause him to have issues.

Thanks!

 

Why not post your problem here for help in diagnosing. What if your car has a problem that damaged your BCM? Then you would have 2 bad BCMs. If you do the swap, there is a 30 minute programing process to be done before the car will start. Good luck
-----------------------------------------
From the SM
-------------------------------------
30 Minute Learn Procedure
Turn ON the ignition, with the engine OFF.
Attempt to start the engine, then release the key to ON (vehicle will not start).
Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
Turn OFF the ignition, and wait 5 seconds.
Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the password on the next ignition switch transition from OFF to CRANK).

Important
The vehicle learns the password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.


Start the engine (the vehicle has now learned the password).
With a scan tool, clear any DTCs if needed (history DTCs will self clear after 100 ignition cycles).

 

Thanks. I actually have a thread started, but I'm getting a bit discouraged and impatient with the troubleshooting. Mainly because I live at an apartment and have to wait until the weekend to do any work on the car at a friend's house.

http://forums.corvetteforum.com/c5-t...al-issues.html

The current codes are:

10 P1571
28 No COMM
58 U1040 HC

The power windows don't work. The door jam wiring seems OK from what I can tell. The driver's side started working out of the blue. I started the car, turned it around for better access to the passenger side, took the passenger door panel off and
tapped it a bit with no luck. I tried the driver's side again after this and now it's no longer working, either. The headlights dim when I press the button and the relay clicks, so I would think it has to be a short somewhere or seized motors. I guess I need to remove the speakers or the rubber seal to access the motors since the door panel being off doesn't expose anything.

The headlight motors, dash lights, parking lights, and taillights do not work when turning the lights on. The headlights work, but have to be propped up manually. The parking lights, brake lights, and dash backlights do work at other times (dash illuminates with driver's door open).

The ABS and TCS lights are shown on the dashboard. The traction control system is disabled based on wheelspin.

I will try cleaning all grounds. I found the diagram Bill Curlee posted, but I'm not sure how to clean the female pin receptacles. Also, is there a diagram that shows what's grounded on each of the G### points? If you have any electrical schematics for the electrical networks in this car, I'll work my way through them to try and figure out how to better troubleshoot.

I also read an old thread about measuring resistance from the STAR connectors and a chassis ground and checking to see if it's near 750 ohms. I did not see much detail on this, so any further info is appreciated.

Thanks

 

Thanks for the excellent links.

In this link:

http://forums.corvetteforum.com/c5-t...locations.html

Where exactly is ground G103?

It's labeled on this picture as being near the driver's wheel well:



I'm wondering if this could have something to do with the 28 - TCS No communication message. I cleaned the two front grounds on the frame rail and two engine compartment rear grounds. One rear ground near the battery (G104) on the frame rail and one on the driver's side frame rail that I'm now thinking is actually G105 since it was a ground strap braid.

So, that means G103 was not cleaned which is a definite factor since the frame rails were painted in some areas after the collision and G101 and G102 were bolted directly on top of paint prior to me sanding it off.

I also see a harness that goes to the EBCM with a three pin connector that is bolted down by the same bolt that secures the washer fluid container. The bracket is metal, but that bolt doesn't seem to be a ground since it's mounted on the non-metallic inner fender and shows no conductivity to known grounds. See pic that I took:



If this is not it, where is G103?


PART TWO:

Here are my readings to ground from the STAR connectors. These were taken with ignition off, but the battery was still connected. I can't see well enough to read connector markings, but these are the colors. Is there a cross-reference chart that relates the colors to modules?

STAR Connector 1:

• Purple - 3.58k ohms
• Green - Infinite
• Orange - 10.7k ohms
• Light Blue - Infinite
• Dark Blue - 10.7k ohms
• Gray - Infinite
• Blue with White Stripe - Infinite
• Pink - 10.7k ohms
• White - Infinite
• Light Green - 10.7k ohms

STAR Connector 2

• Purple - 3k ohms
• Brown - 10.7k ohms
• Tan - 10.7k ohms
• Brown with White Stripe - 10.7k ohms

I appreciate it.

 

Found this post just now regarding wire colors...gonna paste it here for reference:

http://forums.corvetteforum.com/1574771254-post17.html

 

Thanks. I did check that ground.

Any idea if the resistance to ground on any of the pins seems off?

 

Pop out the door accordion tubes, fish out the TWO connectors in each door A pillar frame hole. DISCONNECT both connectors on both doors. INSPECT the female pins in the female connectors. Look for corroded burnt and pins that are spread apart. The poor connections causes the BCM to have serial buss issues.

I use a spare male pin to test the grip of the female pins. The female pins should have a nice tight grip grip on the male pins.

"I know what your thinking!!!!!!"

Its a FREE quick check that more often than not, corrects the no comms issues.

BC

 

I see your into it elbow deep with your grounds & wires but 1 thing u can do before u start all this is take the car to a local shop who isn't retarded & have them hook up a tech 2 to the bcm & make sure the tech 2 is able to read the bcm,this way it knocks out the possibility of the bcm being bad & u will know right then if it is or not,if. The tech 2 isn't reading the bcm u know where your problem lies,if it does read that's good news & u don't have to spend the money on one & then proceed to start checking on your ground/sensors & wire/electrical issues,I'm going thru the same thing right now with mine

 

Made quite a bit of progress today.

I unplugged the door harnesses and nothing changed. I was laying on the passenger floorboard and didn't feel like getting up, so I just decided to start checking fuses again. The parking/tail lamp 10A fuse read 80-90 ohms rather than <1. It turns out that it was blown. I guess I was reading the resistance of the circuit since I was simply touching the pins on top with it plugged in.

Somehow, this fixed the headlight motors, instrument panel, and obviously parking and tail lamps. So, I can now drive it without being concerned about getting home before dark.

I decided to dig into the doors and isolate the electric motors. I connected the passenger side straight to the battery and it was still seized even with no load. I took the motor apart and the brushes and commutator don't look too great. It looks like both window motors may actually be bad. I thought that this was too unlikely and that it had to be something else that controls both doors, but I may be wrong.

If this is the case, the only remaining issue is the ABS/TCS lights.