Coolant temp pegging out!!

blackcoal

blackcoal

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Jan 2, 2011
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On my 03 the coolant temp gauge is pegged out all the way on the max side all the time with the key on.

Tried a new sensor no change, unplugged it and tried no change. Is it shorting it self out in the wiring harness?

Anyone else ever have this problem?
 
dangerous06 said:
I assume the coolant is full. Ohm out the wires to the ECM plug.
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Has no continuity at all. Guessing a wire shorting out between sensor and ecm? Anyone have a wiring diagram that would tell me what pin it is on the ecm plug
 
Ended up pinning it out at the ecm harness and at sensor plug. The wires are good no short. What to check now? Could there be a short between the ecm and the cluster or is it an ecm issue? With a scan tool hooked to truck it will read coolant temp correctly just the cluster is always maxed out.
 
You checked for shorted wires but did you check for continuity (broken wire) if so and there all good most likely you have a faulty guage.
 
Did some more checking on this and I'm thinking it might be in the ecm.

Swapped clusters problem still is there.

Check engine light is on with an engine temp code.

Engine fan runs all the time.

If you hook a scan tool to the truck it reads the correct engine temp....

Any ideas?
 
crlush said:
You checked for shorted wires but did you check for continuity (broken wire) if so and there all good most likely you have a faulty guage.
Click to expand...



Wires from ecm to sensor are good. Could it be wires from cluster to ecm?
Anyone have a diagram for that
 
I've got an '06/07 ECM that I use as a test unit that has a bad water temp circuit... you hook the computer up, and the gauge pegs out.
 
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