Electrics: Camshaft Position Sensor Wiring Problem

[abnxc90]

Hello, I just wondered if anyone has had this issue / solved it.

I have a 52 reg D5 XC90 auto which has an intermittent power loss which lasts half a second and then back to normal. This happens under normal cruise at higher speeds. Some days this doesn't happen and others it happens a number of times. The associated code which I clear each time and then appears in memory after the fault is 300A "camshaft position (CMP) sensor, faulty signal". I've changed the sensor for a new one and the symptoms remain the same. I presume this therefore means there is a fault in the wiring to the sensor.

I'd be grateful is anyone has a wiring diagram for this sensor to the ECU or has solved this problem in the past.

Thanks for any help.

[SwissXC90]

I can help you with wiring but please tell me what model year (MY) your XC90 is.
Unfortunately I cannot translate "52 reg" into a model year.

[abnxc90]

Hi Tony, the date of registration is January 2003 so the car will be late 2002 or very early 2003. Thanks for your help.

[cheshired5]

Originally Posted by abnxc90

the date of registration is January 2003

It will be a 2003 model year.

[SwissXC90]

I will approach this from the viewpoint of tracking down an intermittent electrical contact problem.

For reference I found a 2005 wiring diagram, it will be similar (I hope) to the 2003 model.

There are two Camshaft Posiiton Sensors:
7/172 Position sensor, camshaft, intake side
7/173 Position sensor, camshaft, exhaust side

Both are wired directly from the sensor to the ECM, without any connectors in the way. This is done for maximum reliability.

So for intermittent contacts you can only have the following issues:
Poor connection at either connector (sensor or ECM)
Wiring loom fault (abrasion with intermitten short to ground, or a wire break)
ECM fault (faulty inputs for the camshaft position sensors)


I recommend the following:
Inspect and clean the sensor connector, and inspect and clean the ECM connector. Use contact cleaner spray to clean them.
Be suspicious of any connector which is dirty, oily, greasy, or corroded,
Ensure the pins has a sufficiently tight fit on their mating surfaces, so that no intermittent contacts can result. this can be dificult to determine unless you have a mating pin you can use to check pin contact force.
Inspect the cabling from the sensor, along the loom, to the ECM.
Look for signs of adbrasion through vibration and rubbing on any surfaces.
Look for any signs of damage anywhere: such as cable loom pulled tight over any obstruction.

Both sensors have a red, a black and a blue wire
Red and black will be the power, and blue the signal
But all 3 are equally important

Red goes to ECM pin A:57
Black goes to ECM pin A:65
Blue goes to ECM pin A:47 for device 7/172 and to pin A:27 for device 7/173

Good luck!

[abnxc90]

Thanks Tony - I didn't know that there were two camshaft sensors so I shall find the other one first!

[SwissXC90]

Originally Posted by abnxc90

Thanks Tony - I didn't know that there were two camshaft sensors so I shall find the other one first!

My name is not Tony!

[abnxc90]

Haha, sorry about that, not sure where I got that from.

[Ducklakeview]

Originally Posted by abnxc90

Haha, sorry about that, not sure where I got that from.

Swiss Toni?

+ YouTube Video

Mike

[abnxc90]

I thought I would post up the final solution to this in case it helps someone in the future. The XC90 D5 has only one cam-shaft position sensor. I think the reference to two must be for a different engine. Even though the terminals looked in good condition, this was fixed with a spray of WD40 Contact Cleaner on the contacts of the electrical connector at the cam-sensor, an easy fix!