Volvo V70 VVT-solenoid trace

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Volvo V70 VVT-solenoid trace

Postby kukushka » Sat Jan 13, 2018 11:15 am

Hello everyone,

Can you double check this waveform before I contact the customer. It is a Volvo V70 2.4 gasoline -06 with an active fault code about the "VVT-signal".

The solenoid receives a healty +15V, but the signal is less powerful. Coil resistance is in spec. So,

-Voltage drop from the solenoid to the ECU?
-Poor ECU grounding (no other faults than this) ?
-Or a broken solenoid?

To my understanding, if the solenoid coil or mechanics would be to blame the current would be too low, but the voltage should be the same as the supply? In the trace it reads only 10.5V.

So my conclusion is that the solenoid is not faulty, at least by this measurement?
Attachments
V70_-.psdata
(5.77 MiB) Downloaded 84 times
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Re: Volvo V70 VVT-solenoid trace

Postby landroverman1958 » Sat Jan 13, 2018 11:53 am

Hi have you checked the oil level?oil level is very important for the vvt,also there is probably a criteria to be met before the vvt operates,engine rpm over a certain speed,also check the duty cycle to see if it changes with rpm,it may be the oil screen of the vvt solenoid may have a blockage or the actuator,is sticking,check on a scan tool if the desired valve movement matches the actual, hth.
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Re: Volvo V70 VVT-solenoid trace

Postby volrem » Sat Jan 13, 2018 2:18 pm

What's the actual fault code?

This measurement doesn't give enough information. Too low timebase and no current trace. Also should measure power and ground at the same time also.

But from what I see there is nothing in voltage trace that could cause fault code.


You could get fault code for VVT solenoid for several reasons.

Faulty VVT electrically
Faulty VVT mechanically (sticking)
Faulty power or ground (control)
Faulty oil pressure
Wrong cam position.

Post actual fault code and make new measurement with power, ground and current.
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Re: Volvo V70 VVT-solenoid trace

Postby kukushka » Sat Jan 27, 2018 7:05 am

Hi,

New captures with supply, signal and current.

The code is ECM-6400. First it was signal too low, and now open circuit. Resistance at the solenoid is in spec.

In my opinion, the voltage drop from to load to the ground causes a situation with no current?

Supply voltage is OK, the solenoid is not drawing any current and the return voltage is too low but stable. In the file V70_2 I dipped the gas a bit to observe changes in the control signal width.

Are these spikes common in the trace at file V70_2, I did not put filtering on? The scale jumps up and down because of those.

I used Volrem's *.psdata files from the library as a base so the timebase should be more suitable.

The forum does not allow attachment's over 30MB so I uploaded them to Skydrive, here are the links.
https://1drv.ms/u/s!AtKRD0pG9zEGjT4EXyuIlMowYzWA
https://1drv.ms/u/s!AtKRD0pG9zEGjT3WhZs2JQd2_iNP
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Re: Volvo V70 VVT-solenoid trace

Postby volrem » Sat Jan 27, 2018 10:34 am

First of all don't use auto-scaling for voltage. Always select voltage range yourself.

Either lower sample rate or save only one waveform buffer to get smaller filesize.

Supply voltage is OK. Control is OK. But beacuse of almost open circuit in solenoid there is no current and control signal voltage stays low (not enough voltage get past solenoid).

So yes you have a faulty solenoid.
Last edited by volrem on Sat Jan 27, 2018 1:15 pm, edited 1 time in total.
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Re: Volvo V70 VVT-solenoid trace

Postby kukushka » Sat Jan 27, 2018 11:01 am

Is it common for a faulty solenoid to have a normal resistance unplugged, but almost open when energized?
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Re: Volvo V70 VVT-solenoid trace

Postby volrem » Sat Jan 27, 2018 1:13 pm

kukushka wrote:Is it common for a faulty solenoid to have a normal resistance unplugged, but almost open when energized?


Yes. There is almost no current load when measuring resistance. Circuit may show perfect resistance value unloaded but fail instantly when current is applied.

There are very few placed where resistance measurement is accurate. I almost never use it.

Circuits that work under load (small or big amount) have to evaluated always under real operating conditon.
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Re: Volvo V70 VVT-solenoid trace

Postby kukushka » Sat Feb 17, 2018 6:52 am

Hello,

Here is the capture with a new solenoid. The current looks a little different than from Volrem's capture, but I used the 30A TA189 so that might explain the different waveform? On the other hand, I think it is clear that the current is not rising as fast, and has nothing to do with the clamp.

The duty cycle was 44% so that might explain the lower current?

In my opinion, the solenoid should be working but the car is still throwing the same CEL. What I noticed but only afterwards was that upon starting the engine, the camshaft sprocket moves in and out of about 5-10mm, so there could be excess play in the VVT gear causing this CEL. The CEL is about intermittent signal, so it was triggered on start-up.

Too bad I did not take a capture when starting.
Last edited by kukushka on Sat Feb 24, 2018 9:16 pm, edited 1 time in total.
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Re: Volvo V70 VVT-solenoid trace

Postby volrem » Sat Feb 17, 2018 1:55 pm

kukushka wrote:Hello,

Here is the capture with a new solenoid.


Brand new or used?

kukushka wrote:What I noticed but only afterwards was that upon starting the engine, the camshaft sprocket moves in and out of about 5-10mm..


Really? I have see about 3mm play at most. It should be leaking oil a lot with so much play (moves out from gasket).

Never seen that play could cause DTC. So either sticking solenoid, oil pressure problem or incorrectly installed VVT unit. Worn VVT unit could cause inside leak also.
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Re: Volvo V70 VVT-solenoid trace

Postby kukushka » Sat Feb 17, 2018 7:34 pm

It is new but non-oem part. The current draw is certainly very different. Also the voltage. I wonder would someone have an insight into this, how does the Volvo ECU deem the signal faulty, does it measure current, voltage or the actual advance of the cam, that would help to determine is the signal ( and the non-oem solenoid) too different. In my opinion the solenoid can not function in the same way as there is such a big difference in those traces.

No oil leaks or other listed problems. There were no play with the belt on using hand tools.
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