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Old 01-29-2004, 09:08 PM   #1
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Default PCM Electrical readings

I posted awhile back a problem with inadequate voltage readings that my scanner was picking up "through" the PCM. I also checked the red connector for the PCM circuits (WC7~10.5 v, WC8~10.5v, WC9~ 7.9v). I pulled the fuses under the hood and was floored at how they looked tarnished (from heat) not corroded, but tarnished. Cleaned them up with a pencil eraser, and fabricated a strip the same size of the prongs on the fuses from copper (.015 thick) and wrapped some 1000 grit wet-dry sandpaper over the end, and cleaned the sockets as well........unbelievable (also did the fuse box under pass side dash-behind glove box) . Voltages jumped to WC7~14.4, WC8~14.4, WC9~10.9. Before, while the car ran, the voltage would eventually drop to 9v, and activate the "Volt" light, now there is no drop. I'm psyched, except wondering if anyone else has looked at their voltage readings while hooked up with the scanner, and what were they? The PCM may only require roughly 11.0 v, dont know, but would like to get the general concensus. Appreciate any feedback.
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Old 01-29-2004, 11:45 PM   #2
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So, you're dropping voltage through the fuse receptacles, if I understand you correctly. That is some excellent troubleshooting. My car is relatively new and I don't have a scanner, but I'll have to remember that for future reference. Did you clean all the active fuse sockets, or just selected few? What are those voltage parameters WC etc?
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Old 01-30-2004, 12:22 AM   #3
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Yes (and thanks), I was getting a voltage drop enough to trigger the volt light on the dash, but was still pumping 14+ volts back to the battery. The PCM gets it power feed from the ignition, and fuse blocks from under the hood. The WC designation is the name of the circuit connector "prong" on one of the three connectors on the PCM. -(White, Red, or Blue). WC7 and 8 are battery feeds that should read "battery volts", WC 9 is the ignition feed to the PCM (ignition volts), and that is the one I'm questioning. Is 10.9 volts adequate to run PCM circuits that feed off that circuit? Thanks for the reply. BTW, yes, I cleaned all of the sockets and fuses.
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