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Discussion Starter · #1 ·

I purchased a used 2002 VW Passat (30v V6) for my son that wasn't running at time of purchase. I bought it as a project car for he and I to work on and have it be his first car. The timing tensioner pulley had failed and wrecked both heads. I've been able to navigate that and have replaced both heads and have the engine back together. However, when I was checking the codes, I am receiving a P0118, which is the coolant temperature sensor. No problem. Ordered a new one but when I went to replace it, I found the wiring connector had been broken before (and cobbled together). The result is that I have 4 wires that I need to put in a new connector but have no idea which wire goes where.

I've been researching online trying to find anything that would help me identify the wires - but no luck. I either haven't found the correct information yet, or VW isn't consistent in their wiring colors. I also have the Haynes Repair Manual but haven't been able to find anything that corresponds to my wire colors.

What I have in terms of wire colors is:

Yellow with Brown stripe
Blue with Brown strips
Grey with Red Stripe

With the ignition turned on, I am getting around 5 volt reading on the Yellow Wire with Brown Stripe but nothing on any of the others.

Can anyone help me out with this one?

Appreciate it!


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Per Bentley manual schematic 69/6, /15, & /16:
The coolant temperature sensor contains two independent sensors (thermistors), G2 for the instrument cluster (temp gauge, et al) and G62 for the ECM. Each uses two wires. G2 connects to pins 1 & 2; G62 to 3 & 4.

Connector pin, wire color, function:
1 Blue/Brown: G2 wire to cluster (via 10 position black connector in ECM box, pin 9)
2 Brown/Yellow: G2 wire to cluster signal ground (via 10 position black connector in ECM box, pin 5; spliced in engine harness, also serves coolant level sensor)
3 Gray/White: G62 wire to ECM signal ground (pin 108, spliced to gray/white and black in engine harness for several other sensors, e.g. black wires on camshaft position sensors)
4 Brown/Gray: G62 wire to ECM pin 93

Seeing that your colors don't match Bentley, it might be advisable to open up the ECM box and ohm out the wires. VW is German, so the wire colors ought to match.

Park the wipers "up" to gain access to the plastic plug in the black plastic at the bottom of the windshield. Pop it out (don't lose it!) and that gets you access to the fifth ECM box cover bolt. You just need a long, skinny, extension.
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