7 replies to this topic

[Dan the bubblehead]

Hey, this is my first time trying a post here. I have a 98 V70R with 130K on it. Yesterday car woldn't start, so I read the code and got Cam Posit Sensor CKt malfunction as the code. I found the sensor and tested the connections according to Chilton's (I am not sure if I trust the values Chilton listed). I just wanted to know if anyone knows the correct readings I should get from the connection plug (Volts on pins 2&3 and ohms on pin 1). I am testing the "car" side of the connector to verify that the sensor is receiving the correct input from the ECU. Since the CMP sensor is just a fancy switch, I assume I would need an oscilloscope in order to determine if it is broken or not. Trying to prevent just throwing parts at the car. Any help is appreciated.

Edited by Dan the bubblehead, 16 March 2006 - 09:23 AM.

[TheMan5952]

a cam sensor will keep the car from starting. I would just replace it.

[larryo108]

Shameless plug. But if it does happen to be the Camshaft Position Sensor that needs to be replaced. I have a brand new one in my garage that I bought for my car and never used. I have a 1998 V70R AWD also. If you need to repalce it, e-mail me at larryo108@bellsouth.net or hit me up on AIM at LarryOvern. I'll sell it for $100 plus shipping, which is cheaper than you will find anywhere else.

As far as the voltages. I would have to check that at home. I don't have the info here at the office.

[WhiteT5]

The ECU isn't going to send any data to the sensor; it's the other way around.

[850-Turbo]

Hey, this is my first time trying a post here. I have a 98 V70R with 130K on it. Yesterday car woldn't start, so I read the code and got Cam Posit Sensor CKt malfunction as the code. I found the sensor and tested the connections according to Chilton's (I am not sure if I trust the values Chilton listed). I just wanted to know if anyone knows the correct readings I should get from the connection plug (Volts on pins 2&3 and ohms on pin 1). I am testing the "car" side of the connector to verify that the sensor is receiving the correct input from the ECU. Since the CMP sensor is just a fancy switch, I assume I would need an oscilloscope in order to determine if it is broken or not. Trying to prevent just throwing parts at the car. Any help is appreciated.

With ignition ON:
Pin 3 should have 12V(Batt).
Pin 2 should be about 5V
Pin 1 is ground, so you get zero ohm

If the sensor is bad, I'd go to a boneyard rather than get a new one.

If the above test shows no problem, there MAY be a way to check the CMP. I have not tried this myself, but from the reading how the circuit works, this seem like the logical result.

You need to break the insulation on the wire going to pin #2. Now measure at the exposed wire. Ground the other probe and crank the engine. You should see varying or pulsing voltage readings on pin 2.

If you have the CMP out, switch ignition "ON" (don't crank) and pass a piece of metal between the Hall Effect sensor. You should see varying voltage readings on pin 2 wire. I think any magnetic metal would do, but I'm not sure.

If you get pulses, then the ECM should see it as well and the CMP is fine.

[Dan the bubblehead]

with the ignition on I am getting:
Pin 1: 100 Ohms
Pin 2: 12V
pin 3: 12V

According to chilton's, I should be getting 5V on pin 2. Any recommendations?

[850-Turbo]

with the ignition on I am getting:
Pin 1: 100 Ohms
Pin 2: 12V
pin 3: 12V

According to chilton's, I should be getting 5V on pin 2. Any recommendations?

Assuming the ECU is ok, it sounds like the wire harness might be shorting between wires, somewhere along ECU and the CMP connector.

Could it be possible that the CMP wire harness going back to the ECU is melted together against the exhaust?

The 100 ohms may not necessarily be bad. The 12v at pin 2 is not good, though.

[Dan the bubblehead]

I will check the harness sunday. I have to work tomorrow. It is pretty cramped in there and I just had eye surgery so I can't see too well. Thanks for the tip. I'll check it out.
Dan