PCM short circuit?!
Thread Starter
On The Tree
Joined: Jan 2010
Posts: 177
Likes: 1
From: Belgium
PCM short circuit?! I'm wiring my harness on the LQ4 and I have an issue with the PCM
Here is what I did:
PCM (blue connector) pin 1 to negative battery terminal
PCM (blue connector) pin 57 = C2 pin B8 (2 orange wires) receives the perm +12V
Once I put the blue connector into the PCM, my main fuse burns.
Am I doing something wrong?
Harness is from a Silverado 2006
Here is what I did:
PCM (blue connector) pin 1 to negative battery terminal
PCM (blue connector) pin 57 = C2 pin B8 (2 orange wires) receives the perm +12V
Once I put the blue connector into the PCM, my main fuse burns.
Am I doing something wrong?
Harness is from a Silverado 2006
Last edited by mjollnir; Aug 29, 2010 at 01:04 PM.
Thread Starter
On The Tree
Joined: Jan 2010
Posts: 177
Likes: 1
From: Belgium
I don't have a spare PCM (can't find that easily in Europe 
)
I just tested again, I only connected big red terminal to battery +, and the black wired terminal to battery -. Then I mesured voltage between pin B7 and B8 of connector C2 (underhood fuseblock), it reads 3.30V. I should have 12V there right?
Some more info: no short circuit between those 2 pins (reads 0.6V when harness power is unplugged) so I guess the PCM has a small battery to keep some settings like date/time when you change your main battery.
I don't know where the short comes from
)I just tested again, I only connected big red terminal to battery +, and the black wired terminal to battery -. Then I mesured voltage between pin B7 and B8 of connector C2 (underhood fuseblock), it reads 3.30V. I should have 12V there right?
Some more info: no short circuit between those 2 pins (reads 0.6V when harness power is unplugged) so I guess the PCM has a small battery to keep some settings like date/time when you change your main battery.
I don't know where the short comes from
Last edited by mjollnir; Aug 30, 2010 at 01:38 PM.
Trending Topics
Thread Starter
On The Tree
Joined: Jan 2010
Posts: 177
Likes: 1
From: Belgium
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo Thread Starter
On The Tree
Joined: Jan 2010
Posts: 177
Likes: 1
From: Belgium
Thread Starter
On The Tree
Joined: Jan 2010
Posts: 177
Likes: 1
From: Belgium
The problem was evident when I opened the PCM:
A few shorts between some pins. Bad design there GM!!
The pins are easily pushed inside the PCM if the connectors are not perfectly aligned and parrallel to the PCM
Pins put back where they're supposed to be
Let's plug the OBD2 now
A few shorts between some pins. Bad design there GM!!
The pins are easily pushed inside the PCM if the connectors are not perfectly aligned and parrallel to the PCM
Pins put back where they're supposed to be
Let's plug the OBD2 now
