Cam sensor trigger wheel torque + cam sensor resistance - 2002 XC70

Post by **scot850** » 05 Sep 2024, 15:43

I had to remove this to clean it and the area around the cam seal. What I can't find is a torque value for the trigger wheel. it has a long 10mm headed bolt with a M7 thread. I think I found a value somewhere of 17Nm. Anyone know if this is correct?

Just added to this thread. It didn't seem as hard to find info for P80's. Trying to find what the test resistance value should be for a cam position sensor on this car. Measuring this car's it is 900 ohms. I watched Robert's DIY on replacing the cam and crank sensor and and I think he mentioned as long as it was below 1000 ohms it is good. I have no idea if this translates to the P2, even though this year uses the same sensor as a late P80. Is 900 ohms high? The failure code is : P0016 or (643A) ECM-643A : Cam Position - exhaust: Signal too low

Due to the level of work to fit and remove this part, I need to know if this is a good sensor or not.

As usual. any help appreciated!

Thanks,

Neil.

Post by **jonesg** » 05 Sep 2024, 20:06

cam sensor bolt 15 foot lb.

P0016 is cam and crank are not timed properly or cam not reacting when it should.
If you didn't change the oil yet that can cause the problem.

Post by **scot850** » 05 Sep 2024, 20:52

Haven't changed the oil yet. The oil has about 6000 miles on synthetic as far as I recall. The cam CVVT sensor was really clean and has been cleaned and a new gasket with a gauze filter installed with it. I know about oil cleanliness affecting the CVVT solenoid, but had not heard it causing issues with the crank or cam sensors. No crank sensor issues/codes being thrown. I still plan to change the oil and filter but currently my hoist is full of a PITA 00 V70R!!

I believe I'm being a bigger idiot than usual. Having done a lot more reading, as the cam sensor is a Hall effect sensor, I believe I read correctly there is no resistance 'value'. You can only check it with voltage and engine running. No idea how to access the wires to do that.
I'll have to hook up Vida and see if that can give me the data I need. I have ordered a cam and crank sensor made by SMP (Intermotor) on clearance from Rock Auto for $63 CDN (about $45 US) and they should be here Monday. Sure they are not Volvo parts but I have used Intermotor parts when in UK for many years as often they were the only options for older Volvos. They were either ok or rubbish. Mostly good though. What they are like today? No idea. They will be fine for testing purposes and a back up.

Cam sensor bolt? Sorry, to clarify, I am talking about the bolt for the trigger wheel for the cam sensor. Bolt #9 for wheel #8 on the attached link:

https://www.volvocarstorontoparts.ca/a/ ... 28688.html

It is a M7 bolt. 15ft/lb (20Nm) seems high. Mind you I can't tell if it is a usual Volvo 8.8 grade bolt or higher. It was pretty tight. So the 17Nm I read sounds ok too. I'll go with that, and thanks for your help. You have been awesome and much appreciated!

Neil.

canicallyourose · Post by **canicallyourose** » 05 Sep 2024, 23:47

not sure if this helps, but i had a similar code on my volvo once and it turned out to be a wiring issue near the sensor. might be worth checking the connections if you haven't already?

Post by **jonesg** » 06 Sep 2024, 08:18

scot850 wrote: ↑05 Sep 2024, 20:52 Haven't changed the oil yet. The oil has about 6000 miles on synthetic as far as I recall. The cam CVVT sensor was really clean and has been cleaned and a new gasket with a gauze filter installed with it. I know about oil cleanliness affecting the CVVT solenoid, but had not heard it causing issues with the crank or cam sensors. No crank sensor issues/codes being thrown. I still plan to change the oil and filter but currently my hoist is full of a PITA 00 V70R!!

I believe I'm being a bigger idiot than usual. Having done a lot more reading, as the cam sensor is a Hall effect sensor, I believe I read correctly there is no resistance 'value'. You can only check it with voltage and engine running. No idea how to access the wires to do that.
I'll have to hook up Vida and see if that can give me the data I need. I have ordered a cam and crank sensor made by SMP (Intermotor) on clearance from Rock Auto for $63 CDN (about $45 US) and they should be here Monday. Sure they are not Volvo parts but I have used Intermotor parts when in UK for many years as often they were the only options for older Volvos. They were either ok or rubbish. Mostly good though. What they are like today? No idea. They will be fine for testing purposes and a back up.

Cam sensor bolt? Sorry, to clarify, I am talking about the bolt for the trigger wheel for the cam sensor. Bolt #9 for wheel #8 on the attached link:

https://www.volvocarstorontoparts.ca/a/ ... 28688.html

It is a M7 bolt. 15ft/lb (20Nm) seems high. Mind you I can't tell if it is a usual Volvo 8.8 grade bolt or higher. It was pretty tight. So the 17Nm I read sounds ok too. I'll go with that, and thanks for your help. You have been awesome and much appreciated!

Neil.

I didn't pay much attention when I bolted my cam sensor back, tightened the center bolt to "just right" and never gave it a second thought.
my torque wrench doesn't read that low.

you should really use vida.

Post by **scot850** » 06 Sep 2024, 08:26

I did go through Vida and there is no mention of a torque. Just says refit. I also checked in P80 version as it is better written but again nothing. I will take your advice and tighten to just right.

Vida will be next on the agenda once the various items are cleaned and inspected. I am limited with running the car just now as the broken R is blocking getting the XC70 to the garage door to run the engine for a reasonable time to be able to check running values.

Really appreciate your continued input and help!

Neil.

Post by **jonesg** » 06 Sep 2024, 11:25

scot850 wrote: ↑06 Sep 2024, 08:26 I did go through Vida and there is no mention of a torque. Just says refit. I also checked in P80 version as it is better written but again nothing. I will take your advice and tighten to just right.

Vida will be next on the agenda once the various items are cleaned and inspected. I am limited with running the car just now as the broken R is blocking getting the XC70 to the garage door to run the engine for a reasonable time to be able to check running values.

Really appreciate your continued input and help!

Neil.

i was playing with vida and recorded with my phone.
in this order, diagnostics , vehicle communication, select ecm , advanced , select what you want to test.
the video result might give you something to compare yours to.
go full screen in youtube to read the screen better, its just a cellphone camera.

Post by **jonesg** » 06 Sep 2024, 13:36

easy cam sensor function test.

Post by **scot850** » 06 Sep 2024, 14:00

Brilliant! Thanks for both. I had not seen that 2nd video with the simple 'static' test. That will now allow me to test the current sensor and see if it is good or bad. If it appears good I fill reinstall, if bad I will wait till Monday when the Intermotor part arrives and repeat the test and if good install that. I still consider this just a diagnostic process. If either the current part after a good clean, or the 'new' one works, then it will be a part to upgrade down the line.

Thanks for the tutorial on Vida as well. I am looking forward to playing with that and your video really helps!

Now back to the garage to start testing!

Neil.

Post by **scot850** » 06 Sep 2024, 16:37

From the video, they infer that one of the voltages should be around 5V and the other 12V. In this case, Pin # 1 is just under 5V (4.9 ish) and pin # 2 is the ground. Pin 2 and 3 connected give around 5V also? Is this correct for a Volvo?

How do you probe the back of the connector? Volvo has sealed the pins with a rubberised material. Do I have to find a way of trying to push the tips of my probes through there, or can I try pushing a sewing pin into it?

Neil.