Need help with Diagnostic Codes
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Burning Brakes
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From: Beavercreek Ohio Currently own: 1958 Silver Blue Corvette & 1969 Riverside Gold Corvette Coupe
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Need help with Diagnostic Codes
My 2000 stalled on me today and I had reduced engine power enough to limp the last 1/4 mile home.
The diagnostic codes it is reporting are:
PCM P1518H - PCM to TAC Module Serial Data Circuit
TCS C1278H - TCS Temporarily Inhibited by PCM
IPC B0516H - Speedometer Signal Circuit malfunction
Then RADIO, LDCM, RDCM, SCM, and RFA all reported: U1016H - Loss of communications with PCM
Any ideas on how to interpret these codes and actions to take?
Thanks
The diagnostic codes it is reporting are:
PCM P1518H - PCM to TAC Module Serial Data Circuit
TCS C1278H - TCS Temporarily Inhibited by PCM
IPC B0516H - Speedometer Signal Circuit malfunction
Then RADIO, LDCM, RDCM, SCM, and RFA all reported: U1016H - Loss of communications with PCM
Any ideas on how to interpret these codes and actions to take?
Thanks
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From: Cape Coral, Florida
OK, so it looks like we are dealing with a PCM No Comm...the first thing to check is the PCM power and grounds but if you know your way around a DVOM let’s do a voltage drop check across the ignition switch. With engine running and with black lead of DVOM on battery positive and red lead to PCM fuse 23 and then 16 test points see what you see on the DVOM for both... you should see maybe .1 to .2 volts...also see if those 2 fuses aren’t blown...you also want to see if you are getting full voltage AT the PCM...I don’t know if you know how to back probe a connector but you need to back probe pins 19,20, and 61 at the PCM with engine running...that’s pink (19) and 2 orange wires (20 and 61) on the C2 Connector...the PCM ground is G106 and I believe that one is above the engine starter.
Thread Starter
Burning Brakes
Joined: Jun 2008
Posts: 913
Likes: 1,184
From: Beavercreek Ohio Currently own: 1958 Silver Blue Corvette & 1969 Riverside Gold Corvette Coupe
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Thanks C5 Diag!
I don’t know how to do those check other than checked the fuses and they are not blown.
I will take it in to a mechanic and get some help.
I don’t know how to do those check other than checked the fuses and they are not blown.
I will take it in to a mechanic and get some help.
Moderator, Tech Contributor
Joined: Sep 2013
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From: Cape Coral, Florida
I’d think you’d be better off taking it to a diagnostic shop if you can find one...not all mechanics are diagnosticians but all diagnosticians are mechanics...big difference !!
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Thread Starter
Burning Brakes
Joined: Jun 2008
Posts: 913
Likes: 1,184
From: Beavercreek Ohio Currently own: 1958 Silver Blue Corvette & 1969 Riverside Gold Corvette Coupe
2025 C1 of the Year - Unmodified Finalist
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Just to follow up, the problem was a corroded ignition switch.
once cleaned up, everything is running smoothly now.
once cleaned up, everything is running smoothly now.
Burning Brakes
Joined: Oct 2014
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From: The Rainy Side of Washington State
Interesting.
Just shows how important a properly working ignition switch is.
It's a very critical component and when it goes bad all kinds of weird things can happen.
Glad it's all better now.
Just shows how important a properly working ignition switch is.
It's a very critical component and when it goes bad all kinds of weird things can happen.
Glad it's all better now.
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Burning Brakes
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I agree to C5 Diag on replacing the ignitionswitch .
The ignitionswitch contact surfaces are degraded due to high currents switching for many years and a cleaning the contacts of will only be a temporary solution and not rebuild the damaged contact sets .
The ignitionswitch contact surfaces are degraded due to high currents switching for many years and a cleaning the contacts of will only be a temporary solution and not rebuild the damaged contact sets .