Pcm grounds?
Pcm grounds? I'd like to extend my coolant temperature pigtail in my harness, but it is tied into the grey wire sensor ground back to the pcm. This wire is spliced off the same sensor ground grey wire from my transmission plug.
Do I need to maintain the same sensor ground wire and just change where it is spliced or can I use any of the grey sensor grounds back to the pcm?
Or even change to another pcm sensor ground pin that isn't being used or for a different sensor entirely?
Do I need to maintain the same sensor ground wire and just change where it is spliced or can I use any of the grey sensor grounds back to the pcm?
Or even change to another pcm sensor ground pin that isn't being used or for a different sensor entirely?
What year and motor did this harness come from?
You should have 2 wires from the ECT, yellow and black.
Both go straight back to the PCM. The ground is NOT tied to any other grounds.
Are you sure you have traced back the right wires?
You should have 2 wires from the ECT, yellow and black.
Both go straight back to the PCM. The ground is NOT tied to any other grounds.
Are you sure you have traced back the right wires?
The sensor has a yellow wire and a grey wire that splices into the grey pcm ground from the trans plug.
My wiring diagram is from a Haynes repair book which shows the grey wire is supposed to be a pcm ground. But it shows the trans wire not splicing into the CT sensor ground but having its own ground, which is why I questioned it. .
Also the gauge of wire is consistent from the trans plug to the pcm. And the CT sensor has a significantly larger gauge wire. So my thoughts are that the CT sensor ground belongs in a different pin altogether.
I just got the pinouts printed out so I'll double check some things.
Last edited by ryanleiker; Apr 2, 2014 at 10:29 PM.
It looks like with "isolated grounds oxygen sensors" the trans and CT pcm ground do go to the same pin.
My question still stands though: Can I move the CT pcm ground (grey wire) to another pin or do I need to have it go to that specific pcm ground pin in the connector?
My question still stands though: Can I move the CT pcm ground (grey wire) to another pin or do I need to have it go to that specific pcm ground pin in the connector?
I have a Haynes manual for the '93-'00 models.
And the ground is going straight back to the PCM.
Go over in the stereo and electronics section and ask
Whitebird00. He's pretty sharp on wiring.
And the ground is going straight back to the PCM.
Go over in the stereo and electronics section and ask
Whitebird00. He's pretty sharp on wiring.
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From: Monroe,NY
http://www.lt1swap.com/99-02_vortec_pcm.htm Here is the pinout for the 1999-2002 truck pcms. Blue connector pin 74 yellow wire is engine coolant temp sensor. I did a quick look and didn't see the ect ground going back to the pcm.
http://www.lt1swap.com/99-02_vortec_pcm.htm Here is the pinout for the 1999-2002 truck pcms. Blue connector pin 74 yellow wire is engine coolant temp sensor. I did a quick look and didn't see the ect ground going back to the pcm.
This wire color and shared pin agrees with my harness, along with all the extra wire coming from my O2 sensors.
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Verdad Gallardo Right, I've got that much figured out. But I'd like to extend the wires to the CT sensor and instead of splicing back into the trans pcm ground, can I put it into a different pcm ground pin somewhere that isn't being used?
