I've owned two C5's and a C6 Z51 MN6 Coupe. Ive had numerous Class II Serial Data Buss issues with BOTH C5's. Having had those issues, Ive become VERY knowledgable in troubleshooting and repairing those issues. The C5's also have significant issues with Active Handling /TC due to issues with the EBTCM. Im also VERY familuar with troubleshooting and fixing thos C5 issues.

So,,,,,,Enter the C6. You would think that GM would have a LESSONS LEARNED file some where and maybe fix these issues on the NEXT platform. The C6 now has some of the exact same damn issues.

My Steering Wheel Position Sensor connector is not happy and I get ACTIVE HANDLING MESSAGES. Sort of learned how to deal with that issue by manipulating the connector. Im working on a permenant fix.

Today my wife calls me and says the IPC is going CRAZY

The gauges won’t sweep when the car is turned ON, every warning light on the IPC is lighted, and the gauge is empty with a fuel warning light.

Car still drives fine as the IPC freak out happened as she was driving home from work. When she got home, she shut it down to see if restarting it would clear the issue. Then the car wouldn’t crank.

So,,,I go home to see what’s up and its working fine. NO ISSUES at all.

I guess I will be hitting the service manuals to see how this Class II Serial data CAN buss works (or doesn’t work )

If any body else is or has had this issue, please jump in with any and all information that you have on this problem.

Thanks

Bill Curlee

 

If you haven't replaced your cars battery yet it may be time. All the warnings you listed come with a weak or bad battery.

New battery? Check connections, even at the starter and check grounds.

 

HALJENSEN

Thank you for that recommendation. I hate to throw parts at a problem without being sure that I’ve found the issues so,,, with my wife’s assistance, i monitored battery voltage at the battery this morning after leaving the car sit cover night. Battery voltage before starting was 12.23 VDC. Ah,, that’s not too bad. So, the wife gets in and hits the start button. When the starter first hit, Battery voltage dropped down to 9.2 VDC for a brief second and then the car started.

So,, the 4 1/2 year old battery will start the car but, during cold starts, B+ voltage drops way too low to support proper ECU IPC and BCM operation and Serial Data conductivity.

Just need to figure out what battery I’m going to throw in it.

Thanks for all your assistance.

Bill Curlee

 

Hi Bill.

Thanks for the help in the thread i started earlier. It will come in handy.

Your battery is done. The voltage should at least be 12.6v
I'd go for a optima red top if possible. Had one for 8 years newer any issues.