Map pigtail issues
I have a 6.0 LQ9 from a 2002 Denali. C06 cam with long tube headers, otherwise stock.
My map is always pegged at 105 KPA. In trouble shooting, I found that the inbound wire on the map pigtail is 5 volts as it should. My ground checks out properly also. The outbound wire that should be at 4.5 volts or less under vacuum, shows 12 volts.
Anyone seen this and have suggestions on a fix???? Looking for help.
2002 Denali WHAT? Denali is a trim level. It's like saying 'my 2002 with the chrome rims'.
Are those voltages with the sensor plugged in, or unplugged?
If there is anything on the middle wire/pin B with the sensor unplugged, it's shorted to voltage somewhere. That wire goes from pin B all the way to the PCM at C2 pin 32 with no connectors or splices.
The trim package is unknown. The motor was put into a 77 Camaro and I bought the motor out of vehicle.Originally Posted by blindsquirrel
As for the test, it was tested with the map plugged in and without, with key on. Either way, 12 volts present.
The trim package is Denali. Denali, like SS or GT, was applied to multiple platforms. Different platforms have different wiring diagrams. Yukon Denali (Tahoe)? Yukon XL Denali (Suburban)? Sierra Denali (Silverado)?
You have a short to voltage on the MAP signal return. Unplug PCM C2, key-on, recheck voltage at MAP pin B. If it still has voltage you have a short somewhere in the harness. If the voltage goes away you have a bad PCM.
Thanks. I will let you know what I find.
Turned out that the B pin had a short in the wire. Ran new wire to the pcm, all good now. Thanks for the assist!
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