B0605....ouch...the kiss of death for the BCM..

 

give me a call. PM sent.

 

Dang! It's a good thing he has one coming in tomorrow

Wow this really took off - this should be added to the Electrical issue sticky

Jon I am glad Lucky and Bill have been able to assist as well, looks like soon enough you'll be back on the road

Looking forward to tomorrows tests

Thanks,Matt

 

Before you condem the BCM,,,,lets try to see if your getting the correct power to it. Find, beg borrow or swipe a volt meter and check the ignition switched power to the BCM and PCM.

Heres my Ignition Switch Post and it provides the fuses to check to insure yur getting proper power from the ignition switch at power on.

- C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html

 

BIG thanks to Lucky for all the help over the phone! I am sure we will get this squared away soon as we keep getting closer and closer!

Also, I really want to thank everyone who is pitching in their help! It is GREATLY appreciated as I have no idea WTF I would do if it weren't for you guys!

 

Will do Bill! Tomorrow after work I will swing out somewhere and pick one up and test. I will follow your link there on how to do the test and report back!

 

After speaking with John....here's where were at:

For whatever reason, the BCM started communicating again. As a result of that, and having the PCM, BCM, and IPC shorted on the star connector, we were able to get some codes.

U1255 is a serial data line malfunction - nothing we did not already know. We did get this to reset.

All PCM codes reset as well.

Since communication with the BCM was established, we went for broke, and plugged in the shorting plug, at which time.....all communication ceased.

My suggestion was to short M, B, and G again, to see if communication can be established again. If so, add one system at a time i.e. radio, ESC, HVAC, etc.....and see if any bring down communication.

It's strange that the BCM keeps dropping out, but that B0605 is a deal breaker. While it was only an H code, and did clear, it suggests that something funky is going on with the BCM internal memory.

Since the star connector was being manipulated, I thought it worth a close look at the light green wire, between star connector 1, and the BCM connector C1......just to make sure it's not damaged, etc.

 

Okay I went back over a few things. Added in the purple wire, A I believe it was lucky? Anyways, with the purple wire also jumped in, I lost communication to the PCM and BCM and only had comm to the IPC.

I then went back and jumped in just the last 3 (lt green, dark green, grey) and I re-established communication with the PCM, BCM, and IPC.
On this re-established communication, the ONLY code that came back was the U1255 on the BCM.

Have to call it a night. Have to be up in a few hours for work. Will be back on the grind tomorrow evening!

 

If you have ALL the correct voltages,,,,,see if the engine will start and run. If you dont, the Ignition Switch sounds like it NOT having a good day. Rebuilding it is easy. This is a very common issue and were seeing it more and more as our cars age.

BC

 

So I check these fuses first:

Under Hood Fuse Center

ENG ING1 FUSE# 19
INJR 2 FUSE# 18
THROTCONT FUSE# 17
INJR 1 FUSE# 22
PCM FUSE# 16
F/PMP FUSE# 13

Instrument Panel Fuse block

BTSI BU Fuse# 21
BCM 13 Fuse# 22
IPC Fuse# 19

And they should read battery voltage. If one or some do not, then I proceed to checking the Ignition switch? Thanks!

 

today with M B and G jumped I have communication with the PCM, BCM, and IPC. history code U1255 came back on the BCM again. No other codes. Engine fires and runs!

I plugged the ground plug back in on the 4 wire connector, but no difference.

Now I am going to check those fuses as soon as I can figure out how to use this damn ohmmeter I just bought

If my engine fires and runs now, would that eliminate the ignition relay switch from being the issue?

 

Only one way to find out....take the measurements. I think Bill's suggestion should be followed to cover the bases, and make sure nothing is abnormal with the ignition switch.

 

Under hood fuse center.
Battery- 11.61
#19- 11.58
#18- 11.59
#17- 11.59
#22- 11.58
#16- 11.53
#13- 11.52
Battery again- 11.57

Instrument Panel Fuse block

#21- 11.43
#22- 11.41
#19- 11.46

Battery Again - 11.50

 

I'd let the battery sit on a charger for a while...all the troubleshooting and no running takes it's toll on the voltage.

Good job by the way. Most guys don't get the hang of a meter quickly

 

haha thanks! isn't too tricky

Right now my biggest problem is getting the different leads jumped.... rigging up wiring for it is a pain! Anyone have any easy solutions? The wiring keeps bending, falls off, etc etc...

 

Now that you have an OHM Meter, read EACH star connector terminal to ground and see what the driver for each module reads.

Pin "A" on each plug will read infinate because it goes to the OBDII connector under the dash. INFINATE would be a normal reading.

 

SHould I do this with the key on or off, and read in volts just as I did the fuses? Thanks!

 

KEY OFF. Your reading resistance. Resistance meters DO NOT like voltage!

 

ok so I will be wanting to read OHM? Should I set it to 20M, 200k, 2k, or 200?

 

Start high and then scale dwn till you see where the reading is.

BC