2001 V70 T5 ECM644A Slow Control, Permanent Fault

2008XC70 · Post by **2008XC70** » 21 Aug 2014, 00:21

Hi all,

Wonder what others think of this situation...coincidence or not?

2001 Volvo V70 T5 with 137k miles.

I bought this car a while back and finally dove into it. About two weeks ago, I did the timing belt and water pump. I also did the whole PCV kit replacement as the front intake cam seal had blown out from positive pressure, now there is good negative crankcase pressure. Replaced all cam seals and front crank seal. Dropped the oil pan and replaced the O-rings, as well as the pickup tube seals and now no more leaks around the pan. Replaced the B4 servo cover and linear solenoids and flushed the system with new 3309 spec fluid, did the relearn procedure and no more shift flares. Fresh Valvoline Maxlife 10w30 high mileage oil and new filter as well.

What I don't understand is the "ECM-644A code. Slow control. Permanent Fault". I checked Vida and the camshaft shift angle is within the +/- 3 degrees parameters, its +1.94ish to be exact. I also checked the camshaft adaptation values as all 4 flanks have to be within +/- 7 degrees, all were +3 degrees which tells me the exhaust cam is in the correct position. I spent a good hour making sure the timing was correct.

How coincidental is it that the cam reset valve is failing right after a timing belt change? The only thing I have not checked yet is the resistance between pin 1 and 2. The plug appears to be okay. Also, I don't seem to see any evidence of air bubbles in the oil.

Other than the ecm644a code throwing an eventual CEL, the car runs great! No stalling or rough idle at all. I think when the CEL comes on, the CVVT is disabled, so I probably don't get as good of performance/gas mileage as I could be getting.

Thanks for any advice!

Post by **vtl** » 21 Aug 2014, 08:29

Have you tried to clean VVT solenoid? You need a new gasket too.

2008XC70 · Post by **2008XC70** » 21 Aug 2014, 09:58

I have not tried that yet. What are the chances that its clogged and still serviceable? Would checking the resistance tell me anything other than it being worn out?

Post by **vtl** » 21 Aug 2014, 10:59

No, you need to take it apart and clean gum out.

2008XC70 · Post by **2008XC70** » 22 Aug 2014, 13:41

vtl wrote:No, you need to take it apart and clean gum out.

Okay took the solenoid assembly off and inspected, did not appear gunked up, but I did not disassemble the unit. I took a good, working example from an identical 2001 V70 T5 and will see if that changes anything. I bought the new gasket from the dealer.

Will update after a couple drive cycles.

2008XC70 · Post by **2008XC70** » 25 Aug 2014, 01:41

So far so good, readiness code and no check engine light, also no codes related to that in Vida.