ECM-644A 2000 volvo c70 coupe t5

dandanboi25 · Post by **dandanboi25** » 30 Oct 2025, 08:33

Hi all,
I recently checked my vida for the first time and found code ECM-644A Camshaft control - Faulty position. I then checked the camshaft nominal vs shift angle, at idle the nominal angle is 15 degrees and the shift angle slightly fluctuates around this (+-0.5 degrees) however when on throttle the nominal angle goes to 0 degrees however the shift angle sits constantly at -5.02 degrees. I was wondering if this is normal, I also have a slightly rough idle and intermittent heavy rpm fluctuations causing the whole car to jerk back and forth, however this is fixed my shutting the car off and starting it again.
Many thanks,
Dan

Post by **abscate** » 30 Oct 2025, 11:59

You are one tooth off on your timing belt. You will probably hardly notice this in performance

dandanboi25 · Post by **dandanboi25** » 31 Oct 2025, 00:41

Ahh ok makes sense, timing was probably incorrectly done as the previous timing belt was done at a chain automotive store and ive heard the procedure is pretty complicated. Any ideas on how much work it is to fix and if its necessary?
many thanks,
Dan

Post by **abscate** » 31 Oct 2025, 04:55

Retiming a VVT engine is the same as timing any other Volvo engine - about an hour under the hood removing covers, etc.

If you search for 'understanding cam flank angle ' I wrote a Bible on it a few years back.

viewtopic.php?t=93792&hilit=cam+flank+angle

its non-critical especially if your VVTs are operating (as yours are)

At two teeth off, the system shuts off and will stay stuck at 0 and starting gets harder.

dandanboi25 · Post by **dandanboi25** » 16 Nov 2025, 20:29

Had a good read and was very informative, was just wondering if you used any of the specialist cam/crank locking tools as ive heard they are very helpful but not 100% necessary.
Many thanks, Dan

Post by **abscate** » 17 Nov 2025, 02:29

You don’t really need the cam locking tool to set timing , unless you get the VVT hub off, then you need it to tighten the bolt.
ECM-644A seats on the restart after the cam angle problem is logged, so if you clearcodes after resetting, you need to start twice to check for it.

dandanboi25 · Post by **dandanboi25** » 23 Dec 2025, 20:53

Ok great, Am I correct in reading the 2.3l hpt engine should be timed with the exhaust 1 tooth retarded?
Many thanks, Dan

Post by **abscate** » 24 Dec 2025, 08:28

dandanboi25 wrote: ↑23 Dec 2025, 20:53 Ok great, Am I correct in reading the 2.3l hpt engine should be timed with the exhaust 1 tooth retarded?
Many thanks, Dan

I am sorry that write up is confusing, but I think the answer is no. It refers to this when tightening the VVT bolt, but then goes on to say set timing with marks aligned. If the ECM-644A doesnt code, its right