Computer issues, at the end of my rope. No Comm error...
09-23-2008, 07:44 PM
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Computer issues, at the end of my rope. No Comm error... Corvette 1999 after the latest cam swap I have compounded an existing problem. For the last few months after hitting a bump in the road the gauges would go crazy. Half would max out and the other half would go to zero. I figured the PCM was going bad since I also had the dreaded leaking Delco battery a few years back. Anyways after the cam swap we loaded a tune via HPT and started the tuneing process. After the third upload the PCM seemed to vanish and on the DIC the error message No Comm. was displayed. I jumped the gun a found a PCM vendor and purchased a new PCM fpr 98.00USD and installed the unit. To my amazement on a stock tune the car actually started and drove. Now the problem gets ugly, connected the HPT up and started to up load and Bam No Comm on the DIC agian. I am now having the new PCM reflashed and plan on running the car for a day to let new codes surface and hopefully let the car tell me where the problem is. Have the GM service manuals and a Volt\Ohm meter so the testing will begin. Has anyone had an issue similar?
09-23-2008, 08:44 PM
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Well, from what I've read on corvetteforum.com, the C5 is plagued with lots of ground problems. I'd doublecheck everything, as well as taking a really good look at the pcm connectors to make sure the battery acid didn't corrode the pins any.
09-23-2008, 09:36 PM
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Pins look good, and good point. I am leaning towards the BCM module supplying a positive to ground on the serial bus. Once I get the new PCM in I will be able to check the two Star connections for voltage, where ther should be none. Just puzzled why the PCM would go into a No Comm error and not reset...
