# VVT Solenoid 1.8T AUM Output Test?



## Shleng (May 12, 2008)

Just wondering if it is possible to test the movement of the solenoid which controls the VVT via VAG-COM? Its more the wiring that i would be checking as i am pretty sure that the solenoid works. I'm 99% certiain that this is the cause of my cold start problems. I think that the solenoid should be energised when starting the car from cold to bypass the oil around the tensioner (keeping the chain slack) but this is not happening, and the car looses all compression due to the oil pressure building up within the tensioner. I have temporarily solved the problem by removing the piston that the solenoid moves to divert the oil pressure back to the block rather than the tensioner, but the problem is that the VVT never works when the engine is warm because the piston is missing.
Any info as to wether you can test the operation of the solenoid utilising the wiring loom would be appreciated.
(By the way, the solenoid does not move at all from cold to warm! But i think it should)
Thanks in advance.



_Modified by Shleng at 12:40 PM 4-19-2010_


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## Shleng (May 12, 2008)

Right, completed the putput test to find these results:
EVAP Purge Valve (N80): Short to Ground
Secondary Air Injection Solenoid Valve (N112): Short to Ground
Secondary Air Pump Relay (J299): Short to Ground
Boost Pressure Regulation Valve (N75): Short to Ground
Camshaft Timing Adjustment: Short to Ground
Boost Pressure Control Valve (N249): Short to Ground
Fuel Injector for Cylinder 1 (N30): Short to Ground
Fuel Injector for Cylinder 3 (N30): Short to Ground
Fuel Injector for Cylinder 4 (N30): Short to Ground
Fuel Injector for Cylinder 2 (N30): Short to Ground
These problems do not appear as DTCs, only on the output test. Could it be the loom to the ECU? Does anybody have any thoughts as to what it could be?
Could these be the correct responses that it expects when the car is not running?


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## Shleng (May 12, 2008)

*Re: (Shleng)*

Just had a look on RossTech website to find this:
It is perfectly normal to see a "short to ground" message in the process of running Output Tests. The ECU identifies which output it is currently testing by sending a fault-code number. On many ECU's the full text for this fault code includes "short to ground". Why? Because one side of the actuator in question has 12V on it all the time and the ECU completes the circuit (and turns the actuator on) by pulling the other side to ground.
Maybe the loom is fine, and i need to start looking elsewhere?


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## Dana @ Ross-Tech (Sep 15, 2009)

*Re: (Shleng)*

Please post your Auto-Scan. That may support a Basic Setting test you can run at idle to do a self test.
Has the Oil Psi been checked?


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## Elcroato (May 21, 2002)

Shleng, 
My impression was that VVT was only used for start-up emissions purposes. How does the car run when warm with your current improvisation?


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## Shleng (May 12, 2008)

*Re: (Elcroato)*


_Quote, originally posted by *Elcroato* »_Shleng, 
My impression was that VVT was only used for start-up emissions purposes. How does the car run when warm with your current improvisation?

Yes i think your more or less right about the VVT only affecting the engine at warm up. After looking at the way that the VVT works, i believe that the solenoid should be energised at startup, then relaxed when the engine (and cat converter) are warm (confirmation needed). This would mean that when the solenoid is energised, the oil pressure is directed away (i.e. back to the internals of the engine casing) from the VVT resulting in no timing change. Then, when the solenoid relaxes (engine up to temp), the oil pressure is routed to the VVT to alter the timing dependent on oil pressure. With the way that my VVT is setup now, all of the oil is directed around the VVT as it would be when cold, meaning no change in timing, but when the engine is warm, and the piston should move to direct oil to the VVT, it cannot do this. So basically the VVT is not used at all. 
I have replaced this piston that determains the path of the oil pressure (to the VVT or not) when the engine is warm to find that my MPG improves by about 20% and the car pulls better at high RPM. The problem is, i cannot leave this piston in because as soon as the car cools down, it needs to direct the oil away from the VVT (i.e. energise the solenoid) which it think it is not doing, resulting in my cold start problems.
Sorry if its confusing, please let me know if my eplaination is clear enough.


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## Shleng (May 12, 2008)

*Re: (Dana @ Ross-Tech)*


_Quote, originally posted by *Dana @ Ross-Tech* »_Please post your Auto-Scan. That may support a Basic Setting test you can run at idle to do a self test.
Has the Oil Psi been checked?

All i get from an auto scan is;
16396 - Bank 1: Camshaft A (Intake): Advance Setpoint not Reached (Over-Retarded)
P0012 - 35-00 - -
16684 - Random Misfire Detected - Any Cylinder
or Random/Multiple Cylinder Misfire Detected : P0300
16688 - Cylinder #4 - Misfire Detected
or Cylinder 4 Misfire Detected : P0304
16685 - Cylinder #1 - Misfire Detected
or Cylinder 1 Misfire Detected : P0301
16687 - Cylinder #3 - Misfire Detected
or Cylinder 3 Misfire Detected : P0303
16686 - Cylinder #2 - Misfire Detected
or Cylinder 3 Misfire Detected : P0302
Would this basic setting test allow me to energise the VVT solenoid on demand?
As for the oil PSI, it's feeding the VVT fine.


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## Dana @ Ross-Tech (Sep 15, 2009)

*Re: (Shleng)*

I wanted to see the Auto-Scan details from the car including all of the installed control modules. The info from the Engine control unit would be very helpful.
Example
Auto-Scan


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## Shleng (May 12, 2008)

*Re: (Dana @ Ross-Tech)*

Ahh okay. I will have to wait for the engine management light to illuminate again as i have just recently erased the codes. I will post it up as soon as possible.


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## Shleng (May 12, 2008)

*Re: (Shleng)*

Right, just had a look and the light was on so got some results:
VAG-COM Version: Release 409.1-S

Chassis Type: 1J - VW G/J/B Mk4
Scan: 01,02,03,08,16,15,17,19,22,35,46,56

-------------------------------------------------------------------------------
Address 01: Engine
Controller: 06A 906 032 HJ
Component: 1.8L R4/5VT 0002
Coding: 11500
Shop #: WSC 00000
WVWZZZ1JZ3P060741 VWZ7Z0B5550403
2 Faults Found:
16396 - Bank 1: Camshaft A (Intake): Advance Setpoint not Reached (Over-Retarded)
P0012 - 35-00 - -
18010 - Power Supply Terminal 30: Voltage too Low
P1602 - 35-10 - - - Intermittent
Readiness: 0110 1101
-------------------------------------------------------------------------------
Address 03: ABS Brakes
Controller: 1C0 907 379 M
Component: ESP FRONT MK60 0102
Coding: 0019970
Shop #: WSC 00028
1 Fault Found:
00493 - ESP-Sensor Unit (G419)
014 - Defective - Intermittent
-------------------------------------------------------------------------------
Address 08: Auto HVAC
Controller: 3B1 907 044 C
Component: CLIMATRONIC C 2.0.0
Coding: 11000
Shop #: WSC 00028
1 Fault Found:
00532 - Supply Voltage B+
07-10 - Signal too Low - Intermittent
-------------------------------------------------------------------------------
Skipping Address 15-Airbags
-------------------------------------------------------------------------------
Address 17: Instruments
Controller: 1J0 920 926 A
Component: KOMBI+WEGFAHRSP VDO V13
Coding: 05412
Shop #: WSC 00050
WVWZZZ1JZ3P060741
No fault code found.
-------------------------------------------------------------------------------
Address 19: CAN Gateway
Controller: 6N0 909 901 
Component: Gateway K<->CAN 0001
Coding: 00006
Shop #: WSC 00028
No fault code found.
-------------------------------------------------------------------------------
Address 46: Central Conv.
Controller: 1C0 959 799 B
Component: 1Y Komfortgerát HLO 0003
Coding: 00064
Shop #: WSC 00028
1 Fault Found:
01359 - Internal Central Locking Switch: Passenger Side (E198)
27-10 - Implausible Signal - Intermittent
-------------------------------------------------------------------------------
Address 56: Radio
Controller: 1J0 035 186 D
Component: RADIO SON 0004
Coding: 01403
Shop #: WSC 00028
No fault code found.
End --------------------------------------------------------------------------------------------------
The results may not tell the full story as the VVT has been dissabled internally by removing the piston that pressures the tensioner. This enables the car to start every time from cold as the solenoid has not been energising (i think). I could put the VVT back to standard but then the car would refuse to start, meaning that i would not get any error codes. I'm thinking that the second code (18010) is due to me disconnecting the battery when i was checking the looms.


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## Shleng (May 12, 2008)

On a quick note, i might have inadvertantly solved the problem. There might have been a dodgy connection on one pin to the ECU that has been solved when i pushed it in again as the solenoid is now energising when completing the Output tests and when starting. I will run the car for a few days to see if the problem has now been solved after 3 years!


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## Dana @ Ross-Tech (Sep 15, 2009)

*Re: (Shleng)*

Okay, hope it is fixed. Basic settings 094 should run the self test at idle.


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## Shleng (May 12, 2008)

*Re: (Dana @ Ross-Tech)*

Right its not fixed!







So do i just log in like normal to the engine, then click basic settings? What exactly will this test?
Thanks


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## Dana @ Ross-Tech (Sep 15, 2009)

*Re: (Shleng)*

That should run the self test for the Intake Camshaft Adjuster at idle. It may not run with a fault stored. The other option is Output tests with the engine off, but you have already done that.
http://wiki.ross-tech.com/wiki...00018
Some common problem with the Passat / A4 (B5) chassis also include lack of oil psi due to a restricted oil pump pick-up screen and mechanical chain tensioner problems.


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## Shleng (May 12, 2008)

*Re: (Dana @ Ross-Tech)*

The tensioner itself is fine as i have replaced it to find the same outcome. It has been diagnosed that the electronics are the most likely suspect. The only problem is that if i put the tensioner back to how it should be (with the piston in) it will not idle







Kind of making the test a bit difficult. What exactly will it do to test the solenoid? I might get it to start on 2 or 3 cylinders if im lucky but i am wondering what the test will actually do? Can i measure the block to see what the ECU is demanding/asking for?


_Modified by Shleng at 9:26 AM 4-23-2010_


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