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1999 GMC Sierra MAF Short

Tiny
ANNOYMOUSE69
  • MEMBER
  • 1999 GMC SIERRA
Electrical problem
1999 GMC Sierra V8 Two Wheel Drive Automatic 145k miles

Hi, I have a 1999 GMC Sierra 1500 5.3L. It was recently diagnosed with a faulty Mass Airflow Sensor. It was replaced and ran fine for a hundred miles or so and now it has failed also. OK. There must have a short. I checked the connector and there is 14.1Vdc on the power connection when it is powered up. There is 5Vdc on the IAT sensor (3kohm across this) and on the signal connection. I am not sure if any of this is correct but the thing that concerns me is there is only 3ohm from the “Hot In Run and Start" (the 14.1Vdc) to ground. Is this my short? Could it be the ignition switch? Help!
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Monday, October 20th, 2008 AT 10:12 PM

1 Reply

Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Check the black wires (ground through the PCM) and the black/white wire for good ground. The pink is 12 volt from ECM1 fuse and the tan is IAT signal. The yellow is MAF signal. What kind of MAF did you install?
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Thursday, October 23rd, 2008 AT 7:52 AM

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