PCM low voltage - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


GMC/Chevrolet Truck/SUV When starting new posts, please specify YEAR, MAKE, MODEL, ENGINE type, and whatever modifications you have made.

Reply
 
 
 
Thread Tools Search this Thread
Old 03-16-2012, 04:08 PM   #1
Junior Member
Posts like a V-Tak
Thread Starter
 
Join Date: Mar 2012
Location: Las Vegas
Posts: 26
Thanks: 0
Thanked 0 Times in 0 Posts
Mannyman6600 is on a distinguished road
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
Mannyman6600 is offline   Reply With Quote
Old 03-16-2012, 04:15 PM   #2
Rick
Posts like a Camaro
 
niceguy's Avatar
 
Join Date: Jun 2008
Location: Toronto, Ontario, Canada
Posts: 1,105
Thanks: 0
Thanked 0 Times in 0 Posts
niceguy is on a distinguished road
Default

Welcome to the forum!
niceguy is offline   Reply With Quote
Old 03-16-2012, 04:18 PM   #3
Senior Administrator








Certified Car Nut
 
Mike's Avatar
 
Join Date: Jul 2003
Location: Horseheads, NY
Posts: 15,643
Thanked 997 Times in 774 Posts
Mike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond repute
Default

Welcome to the forum.

I assume your getting a check engine light? What'* the code?
Mike is offline   Reply With Quote
Old 03-16-2012, 04:21 PM   #4
Senior Member
Posts like a Northstar
 
RobertISaar's Avatar
 
Join Date: Jul 2010
Location: Camden, MI
Posts: 615
Thanks: 0
Thanked 0 Times in 0 Posts
RobertISaar is on a distinguished road
Default

are you measuring the voltage at the PCM pin or the sensors?
RobertISaar is offline   Reply With Quote
Old 03-16-2012, 04:32 PM   #5
Junior Member
Posts like a V-Tak
Thread Starter
 
Join Date: Mar 2012
Location: Las Vegas
Posts: 26
Thanks: 0
Thanked 0 Times in 0 Posts
Mannyman6600 is on a distinguished road
Default PCM low voltage

Code is P0122 and I am measuring from the PCM pin
Mannyman6600 is offline   Reply With Quote
Old 03-16-2012, 04:41 PM   #6
Senior Administrator








Certified Car Nut
 
Mike's Avatar
 
Join Date: Jul 2003
Location: Horseheads, NY
Posts: 15,643
Thanked 997 Times in 774 Posts
Mike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond repute
Default

When you have your multimeter + connected to the TPS 5V source, where are you connecting the multimeter - ?
Mike is offline   Reply With Quote
Old 03-16-2012, 07:47 PM   #7
Junior Member
Posts like a V-Tak
Thread Starter
 
Join Date: Mar 2012
Location: Las Vegas
Posts: 26
Thanks: 0
Thanked 0 Times in 0 Posts
Mannyman6600 is on a distinguished road
Default

To the negative pole on the batt
Mannyman6600 is offline   Reply With Quote
Old 03-17-2012, 03:11 PM   #8
Junior Member
Posts like a V-Tak
Thread Starter
 
Join Date: Mar 2012
Location: Las Vegas
Posts: 26
Thanks: 0
Thanked 0 Times in 0 Posts
Mannyman6600 is on a distinguished road
Default

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 ?
Mannyman6600 is offline   Reply With Quote
Old 03-17-2012, 03:26 PM   #9
Senior Administrator








Certified Car Nut
 
Mike's Avatar
 
Join Date: Jul 2003
Location: Horseheads, NY
Posts: 15,643
Thanked 997 Times in 774 Posts
Mike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond reputeMike has a reputation beyond repute
Default

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.
Mike is offline   Reply With Quote
Old 03-17-2012, 03:38 PM   #10
Junior Member
Posts like a V-Tak
Thread Starter
 
Join Date: Mar 2012
Location: Las Vegas
Posts: 26
Thanks: 0
Thanked 0 Times in 0 Posts
Mannyman6600 is on a distinguished road
Default

how can i clear all the codes?
Mannyman6600 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Low voltage, goes up under load bonfp55 Everything Electrical & Electronic 0 11-08-2008 08:10 PM
OBD Says TPS Low Voltage - Steven Webb Everything Electrical & Electronic 17 08-26-2007 11:05 PM
low voltage readimg butkus21 Everything Electrical & Electronic 10 09-08-2005 06:31 PM
P0102 (MAF circuit low voltage) karfreek 1992-1999 2 06-08-2005 12:53 AM
Low voltage J Wikoff 1992-1999 15 01-30-2005 06:39 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 07:28 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.