Hey everyone

I have a 2001 S40 which threw cam position sensor and O2 sensor codes. I got them read at autozone after the check enigne light went off, so I don't have a "specific" code/area to look at. First, I need to test the O2 sensors and determine which sensor is throwing the code. I tested both with a multimeter and neither was obviously bad. Can anyone tell me what the voltage should read at operating temp? .45v?

I also have the cam position sensor to test. I put an LED on the leads and it lit, and got brighter as the engine revved which would indicate that it's producing voltage. The car also has been starting hard, but the sensor seems good. Any ideas?

Any help would be great!
-Dan

 

For the O2 codes there is a couple of things. There is an adapter for one of the sensors that helps reduce interference from electronics that could cause the code. Also maybe even an ECM upgrade.

For the cam sensor codesthere is a possiblilty of low oil pressure. Or if the timing belt was changed the timing might be off slightly. The cams can rotate very easily if the belt is off during replacement.

 

The O2 sensor will not spend any time at a certain voltage. It simply cycles from rich to lean and back again as the computer adjusts the fuel trim. It will cycle up and down close to .45 volts but not stay there. Very hard to see with a digital multimeter. An analog multimeter is better to see the voltage swings with the needle.

My hard starting was caused by a bad fuel pressure regulator. Had to crank the car for 5 to 10 seconds before it fired up. Easy fix but expensive at $90 from the dealer.

Can't help with the cam sensor. Not had that problem yet.