B5425T2 posting P0011

Eikeg · Post by **Eikeg** » 11 Mar 2021, 22:57

Hi. I have a 04 XC70 with 400k km. Persistently, it has been posting P0011 for basically two years. It doesn't seem to be timing belt related. Did the belt, then six months and 13,000km later it started showing up.
Replaced intake VVT and gasket with OEM part. Made sure oil galleys were clean and clear. To no avail.
The wiring harness over the head was in pretty bad shape, baked insulation. Got that sorted out. Still with the P0011. Arg!
Retarded the VVT by loosening the three bolts by half a slot. Nope.
Did an Moly engine flush thinking oil flow issue. Sorry, P0011 again.
Just lost an exhaust valve last month on number 5, so I replaced the head. So nice-n-clean up top. Used cam looking tool, made sure both VVT's (non spring loaded) were fully CW but not so they were at the end of the adjustment slots, and crank was home. Started fine, no codes, even after hitting 4500 RPM going up hill. Drove for an hour, no codes, Then, my wife drives it, and P0011. Runs great, lots of power, no stumbling, behaves perfectly. Oh, and two years prior to that, P0420 starts up. Changed rear O2 sensor, but no. So both codes keep popping up. I think the car is having me on!
Any suggestions?

Post by **RickHaleParker** » 11 Mar 2021, 23:11

ECM-640A ( P0011 ) Camshaft control, intake. Faulty signal
When camshaft control is active, the control module checks the position of the camshaft in relation to the position of the crankshaft. Diagnostic trouble code (DTC) ECM-640A (camshaft intake) or ECM-641A (camshaft exhaust) is stored if the position of the camshaft deviates from the requested position in relation to the crankshaft over a certain amount of time.

Possible source

Faulty control:
Low oil pressure
Poor oil quality
Defective reset valve
Mechanical fault in the variable valve timing (VVT) unit.

You might start by cleaning the reset valve ( AKA VVT solenoid ). Instructions are here. Also clean the electrical connectors while you are at it.

You messed with the VVT alignment. You will need to retime the engine.

Eikeg · Post by **Eikeg** » 11 Mar 2021, 23:19

Hi. Yes, I had looked at this information previously. It was very helpful in trying to isolate the cause.
Since the VVT, VVT gasket, whole head, engine oil, VVT associated wiring is new, and the ECM (Xemodex) is new, it would seem all that's left it the Cam Position Sensor and the VVT hub.

Post by **RickHaleParker** » 11 Mar 2021, 23:25

Eikeg wrote: ↑11 Mar 2021, 23:19 Hi. Yes, I had looked at this information previously. It was very helpful in trying to isolate the cause.
Since the VVT, VVT gasket, whole head, engine oil, VVT associated wiring is new, and the ECM (Xemodex) is new, it would seem all that's left it the Cam Position Sensor and the VVT hub.

When you had the VVT and VVT solenoid off. Did you clean out the oil galleries? Not enough oil pressure to the VVT and the performance would be effected.

Eikeg · Post by **Eikeg** » 11 Mar 2021, 23:28

Hey thanks for replying so quickly!
Yes, I know they are clean especially since the car now has basically younger (175k) cleaned head.

Post by **RickHaleParker** » 11 Mar 2021, 23:30

Eikeg wrote: ↑11 Mar 2021, 23:28 Hey thanks for replying so quickly!
Yes, I know they are clean especially since the car now has basically younger (175k) cleaned head.

Oil galleries running down the block to the oil pump ... ?

Eikeg · Post by **Eikeg** » 11 Mar 2021, 23:39

Good point.
Well when I had the head off, I did inspect those ports. Didn't see, anything out of the ordinary. Though the old head at the back end, by 5, had a lot of carbon buildup. Figured oil flow should be normalized with the replacement head.