where is the PCM relay on a 1990 chevy truck

1990 CHEVROLET TRUCK
97,000 MILES
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PBLACK1948
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need to know I have a low voltage detect code
Dec 5, 2011 at 1:55 PM
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WRENCHTECH
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GM doesn't use a PCM relay. What is your exact code number?
Dec 5, 2011 at 2:28 PM
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PBLACK1948
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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.
Dec 5, 2011 at 5:01 PM
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WRENCHTECH
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Code 43 is an EST code. Is the3 code 12 putting the check engine light on?
Dec 5, 2011 at 8:55 PM
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PBLACK1948
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No it isn't
Dec 5, 2011 at 9:04 PM
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WRENCHTECH
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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.
Dec 5, 2011 at 9:53 PM