Figuring out wiring of harness
Thread Starter
On The Tree
Joined: Jan 2010
Posts: 177
Likes: 1
From: Belgium
Figuring out wiring of harness I'm figuring out wiring of a Silverado 2005 harness to plug my OBDII on. The wiring is out of any car and not connected to an engine for now. Just to its PCM and my laptop.
I have those wired:
Big red harness connector to +12V BATTERY
2 ground connectors to - BATTERY
PCM blue connector C1:
pin 1: grounded
pin 40: grounded
pin 20: +12V battery
pin 57: +12V battery
pin 58: SERIAL DATA (to OBDII connector pin 2)
When I connect my HP Tuners to it, I get a "Unable to locate VCM, please check ignition is on"
What am I missing?
I have those wired:
Big red harness connector to +12V BATTERY
2 ground connectors to - BATTERY
PCM blue connector C1:
pin 1: grounded
pin 40: grounded
pin 20: +12V battery
pin 57: +12V battery
pin 58: SERIAL DATA (to OBDII connector pin 2)
When I connect my HP Tuners to it, I get a "Unable to locate VCM, please check ignition is on"
What am I missing?
You need to connect the PCM power and grounds per this document. Looks like you don't have switched ignition connected. Look at the 99-current diagram.
http://download.efilive.com/Tutorial...20Tutorial.pdf
http://download.efilive.com/Tutorial...20Tutorial.pdf
Thread Starter
On The Tree
Joined: Jan 2010
Posts: 177
Likes: 1
From: Belgium
Thanks for input aknovaman
OBDII: pin 2 DATA ok
pin 4 GROUND ok
pin 16 +12V perm ok
BLUE pin 19 has 12V ok (wired to pink B10 on C2 Fuseblock)
My chinese voltmeter just died.. will get a better one tomorrow and continue debugging
OBDII: pin 2 DATA ok
pin 4 GROUND ok
pin 16 +12V perm ok
BLUE pin 19 has 12V ok (wired to pink B10 on C2 Fuseblock)
My chinese voltmeter just died.. will get a better one tomorrow and continue debugging
Thread Starter
On The Tree
Joined: Jan 2010
Posts: 177
Likes: 1
From: Belgium
I have a ground from my harness connected to - of Battery. It's a quite thin wire.
Should I ground my fusebox somewhere?
On the wire side of pin 60 BLUE CONNECTOR, there is no wire connected. So the 12V comes from the wiring inside the computer (I did mesure directly on the pin soldered to the motherboard with the casing removed)
Should I ground my fusebox somewhere?
On the wire side of pin 60 BLUE CONNECTOR, there is no wire connected. So the 12V comes from the wiring inside the computer (I did mesure directly on the pin soldered to the motherboard with the casing removed)
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All you need to communicate with the PCM via obd2 port is the following.
Blue connector, 19 - switched ignition, 20 -battery, 60 - ground, 58 - obd2 data line to pin 2 on obd2 port, obd2 port pins 4,5 ground, 16 - battery constant.
Blue connector, 19 - switched ignition, 20 -battery, 60 - ground, 58 - obd2 data line to pin 2 on obd2 port, obd2 port pins 4,5 ground, 16 - battery constant.
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I just finish modifying a 05 silverado harness using this site. I use HP tuners and engine is running on a engine run stand, hope it helps you out (i dont have a wire in pin 60)
http://www.lt1swap.com/2004vortec_pcm.htm
http://www.lt1swap.com/fuseblock_obd2port.html
http://www.lt1swap.com/2004vortec_pcm.htm
http://www.lt1swap.com/fuseblock_obd2port.html
Thread Starter
On The Tree
Joined: Jan 2010
Posts: 177
Likes: 1
From: Belgium
Thanks all, I solved my problem!
I had a missing ground (a wire I wrongly labelled as "+" in the past) on pin 1 blue connector. I confirm for silverado harness: pin 60 blue connector has 12V but is not used.
Got to convert my injector harness, lube the engine and I can start it on the bench!
I had a missing ground (a wire I wrongly labelled as "+" in the past) on pin 1 blue connector. I confirm for silverado harness: pin 60 blue connector has 12V but is not used.
Got to convert my injector harness, lube the engine and I can start it on the bench!
