ECM-640A. VVT intake pulley really defect? how do I find out?

millereffect · Post by **millereffect** » 16 Aug 2017, 13:23

-------------------------------------------
-------------------------------------------
Volvo V70, MY2000, 2.4L, petrol, no-turbo, 235Tkm
engine: B5244S2, M56 manual
(V70-I but newer engine with the electronic throttle unit)
-------------------------------------------
-------------------------------------------

Hello,
about 3 weeks ago my CEL came and I get the following DTCs when I read out the ECM with VIDA (see pic attached). The car is running fine. Even smooth idle and driving. I can accelerate like always and feel no power loss.

Possible reasons for the ECM-640A DTC are timing belt jumped a coge, camshaft solenoid defect, oil pressure/oil quality and the VVT pulley itself defect.

I already replaced the soledoid with a new one and did an oil flush and new oil in but no change. The CEL light comes up always after about 20-30 miles.

The VVT unit is quite expensive. To avoid any costly stupid trial an error procedure I like to make sure that it is really a dead VVT unit and not anything else what is the root cause. How can I proof this? Any idea?

What I am also curious about are the warnings which come up the same time the DTC is thrown (see the picture!). Should I take care about these things first to get rid of the CEL warning or do they have nothing to do with each other?

I have VIDA so I could check some things if someone can adive me. I already check desired against actual camshaft angle and they differ for about 0.1-0.3 CA. Sometimes the actual value stays zero while I push the throttle and the desired value ramps up. So this could indeed direct to a partly blocked pulley, right?

The 3rd picture shows the pulley. Does anyone know that this is the right one with the right part number? I wonder that on the drawing it is on the exhaust side but in my car I only have a intake pulley.

Post by **precopster** » 17 Aug 2017, 01:55

When my 2000 V70 had a faulty solenoid I was amazed at how much bottom end torque I regained after replacement.

With these later engines (post 1999). They have solid tappets so you won't hear tappet noise when oil pressure to the head is compromised. Might pay to put some new O rings under the sump ($25 for peace of mind isn't a lot). How many miles on this engine?

Yes that is one of Vida's quirks as they only use one set of diagrams for pre 2004 heads. As long as you have the correct VIN entered you'll be fine.

millereffect · Post by **millereffect** » 18 Aug 2017, 06:51

@precopster
Thank you for your help!

I am not 100% sure about the lack of power on my V70. I mean I feel no real difference. But I drive almost every day 45 miles so in this case it will be rather difficult to notice any slow changes. I doubt it is the solenoid since the old one was still switching when I powered it with 12V. I also replaced it with a new one to make it very sure but I do not feel any changes and the DTC is still there.

The engine runs for about 150.000 miles now. Which O rings under sump do you mean exactly?

I doubt I will be able to avoid the change of the VVT pulley. I mean if it is really defect I will be happy if changing it will solve the problem. I only want to avoid any loss of money in case it was not the pulley.

Does anyone know why the actual camshaft angle stays zero while the desired camshaft angle is rising up? You can read this out in Vida under communication with ECM.

Thank you!!

alanjackson · Post by **alanjackson** » 04 Oct 2018, 03:09

Hello, can anyone tell me if a faulty CVVT solenoid can prevent a 2002 V70 petrol engine from starting ?
I had a problem one morning when I had to crank for about 30 seconds to get the car to start, it had run perfectly for years until then..

A few days later I went out in the morning again and this time it cranks and cranks but wont fire.
Both times the code reader gave ECM 640A codes. The only two times I've had the code and dash warning symbol.

I have read on the forum that the engine should start even without the solenoid plug being on the solenoid, Many thanks, Alan

Post by **abscate** » 04 Oct 2018, 07:01

It should not prevent a start, Alan. Reduction in performance and a code perhaps. Love your music , by the way.

Post by **Ozark Lee** » 04 Oct 2018, 18:01

Did you properly set the CVVT preload? Are the bolts that hold the pulley (number 11) up against either limit in the slots on the pulley? The bolts are typically not centered but they shouldn't be at either limit in the slots.

I think improper preload would cause that error and disable the CVVT. The CVVT hub is not a high failure rate item and if yours is ultimately found to be bad I would have no reservations about replacing it with a pick-n-pull part. The trick at the pick-n-pull is to get it off of the cam without a cam adjustment tool to lock the cam. It is torqued down very tight with a T50 Torx. You will need the cam adjustment tool to replace the hub on your car since the CVVT has no type of key to fix its position on the camshaft.

...Lee

Post by **abscate** » 04 Oct 2018, 20:06

You can bust The hubs off a junkyard car by zip tying the cams together with a big fattie