While replacing my coil harness, I noticed this harness connector had completely disintegrated. Looks as if the previous owner attempted to repair it with silicone gasket maker. Not good. This is located at the rear of the engine, above the cylinder head next to the firewall. Maybe coincidental, but check engine light is now on. I plugged 2 of the leads into corresponding matching color on the female side. Third one does not match. Thanks for any help.

 

Could it possibly relate to your O2 sensor wiring???

 

The cam sensor is back there, it doesn't go to that does it?

 

Guess I will have to get dirty and trace it to its source. Thanks for the suggestions.

 

I can't tell what wires or connector you mean from the picture.
At the back of the head, there are two plugs, a two lead and a three lead. The two lead is for the RPM sensor, the three lead is for the cam sensor. There is also a white/red single lead, that is a test socket to determine that battery voltage is at the head for ignition system.

The lower down, is a connector for the temp sensor if the car is a '95 or older.

DanR '94 964 391,000 miles (157,000 on the new engine)
'08 S60 T5 83,000 miles.

 

Turns out it was the Cam position sensor. Purchased a used, tested and guaranteed unit from Voluparts in Georgia ( U S ). Volvo mechanics must have a "special" tool they use to get the 2 T-30 Torxbits bolts loose. Wouldn't be a bad idea to cut a hole in the firewall to get access.

 

I have removed them with a good Lyles T30 socket. It is tight back there.

 

Got the top one out with a T30 bit and vice grips. No chance on the bottom one. Don't understand Volvo's love affair with this style fastener.