WHERE IS THE PCM RELAY ON A 1990 CHEVY TRUCK

  • Tiny
  • pblack1948
  • 1990 Chevrolet Truck
  • 97,000 miles

Need to know I have a low voltage detect code

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Monday, December 5th, 2011 AT 1:55 PM

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  • Tiny
  • Wrenchtech
  • Expert
  • 20,266 posts

GM doesn't use a PCM relay. What is your exact code number?

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Monday, December 5th, 2011 AT 2:28 PM
  • Tiny
  • pblack1948
  • Member

The code number was 43 however it has dissappeared and the code get now is 12 which means no distributor signal to ECM. Truck runs for a few seconds then stalls. I really need help.

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Monday, December 5th, 2011 AT 5:01 PM
  • Tiny
  • Wrenchtech
  • Expert
  • 20,266 posts

Code 43 is an EST code. Is the3 code 12 putting the check engine light on?

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Monday, December 5th, 2011 AT 8:55 PM
  • Tiny
  • pblack1948
  • Member

No it isn't

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Monday, December 5th, 2011 AT 9:04 PM
  • Tiny
  • Wrenchtech
  • Expert
  • 20,266 posts

That code is for internal ECU error, not distributor communication with the distributor so you may need an ECU but you need to test for injector pulse and spark first.

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Monday, December 5th, 2011 AT 9:53 PM

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