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PCM low voltage

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Old 03-16-2012, 04:08 PM
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Default PCM low voltage

Hello everyone, I want to said this is my first time and I need a lot of help plzs I have a 98 Sonoma 4.3L 2wd 6 cyl I have change almost every sensor before I find out the PCM it'* not sending 5 volts to the the sensors the multimeter it'* only reading 1.2 volts I try replacing the PCM with a used one I reset the passcode and it still sending only the low voltage the scanner shows a tps low voltage error, any idea of what could this be I have already spend a lot of money replacing the sensors thanks
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Old 03-16-2012, 04:15 PM
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Welcome to the forum!
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Old 03-16-2012, 04:18 PM
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Welcome to the forum.

I assume your getting a check engine light? What'* the code?
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Old 03-16-2012, 04:21 PM
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are you measuring the voltage at the PCM pin or the sensors?
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Old 03-16-2012, 04:32 PM
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Default PCM low voltage

Code is P0122 and I am measuring from the PCM pin
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Old 03-16-2012, 04:41 PM
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When you have your multimeter + connected to the TPS 5V source, where are you connecting the multimeter - ?
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Old 03-16-2012, 07:47 PM
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To the negative pole on the batt
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Old 03-17-2012, 03:11 PM
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When I connect the used pcm, even before trying to turn on the truck it had the same scanner code P0122 is it possible that the pcm i got had the same problem or the old code stay there for some reason ?
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Old 03-17-2012, 03:26 PM
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Oh yea, you need to clear any all codes prior to checking for new ones. Some vehicles you can disconnect the battery and the pcm will "lose" the stored codes. Others, it keeps them.
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Old 03-17-2012, 03:38 PM
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how can i clear all the codes?
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