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P0650 and P0801 codes

Old 06-01-2018, 03:01 PM
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P0650 and P0801 codes

i have a 2000 z28, its been having some issues with the transmission shifting and the gauge cluster not working. its throwing 2 codes at me right now, P0650 which is MIL circuit problem, and P0801 which says reverse inhibit control circuit problem(confusing to me since its an auto....). after it started acting up, i replaced the ecm, but with no change. i've also replaced the ignition switch. all i can really find is that it could be due to a wiring short or harness problem, but im not sure which one could cause all that, or really where to look for it, any tips? thanks in adavance

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Old 06-02-2018, 02:57 PM
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Re: P0650 and P0801 codes

Does your SES light work? Does it come on for a few seconds when the key is first turned to "run"? All the engine related idiot light bulbs and the gauges get 12 volts from Fuse 9 "GAUGES", 10 amp. The SES light gets a ground from a driver in the PCM. The signal does not pass through the "solid state" component in the gauge cluster. The PCM monitors the driver to determine if the circuit has the correct voltage, and if it doesn't, sets P0650. The fuse feeds pin A3 on the cluster. The ground starts at PCM pin C2-46, passes through connector C230 and connects to pin A8 on the cluster.

What other problems are part of "the gauge cluster not working"? If the gauges and the idiot lights don't work, check the fuse.

When you replaced the PCM, did you specify you had an auto trans, so it would contain an A4 program? What specific problems are you having with the trans shifting?

Free download of the 2000 factory service manual, courtesy of GaryDoug:

The trouble codes, with schematics are in Volume 2, Part 2, pages 6-1705 (P0650) and 6-1710 (P0801). Auto trans codes are in Volume 3, Part 1. They are P07xx series and P18xx series. Did you personally pull the codes, or did a shop do it?

The dash/PCM schematics are in Volume 3, Part 2 starting on page 8-547.

Last edited by Injuneer; 06-02-2018 at 02:59 PM.
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