P0020 and P0021

[Captain Lockheed]

My friends from Renntech, your assistance and advice please.

Car is a 2005 C2s tiptronic coupe, rhd, 75000 miles. Car is the wife's and is used as her daily/shopping/kids transport.

My wife restarted the car a few seconds after parking it and got the check engine visit workshop warning.

I connected the car to my PIWIS, and got p0020 & p0021. 

I searched on here and saw previous advice to clear the code and see what happens. So I cleared the codes.

A week later it is back.

I took some photo's on my phone camera.

This will get a bit pic heavy.

Edited November 28, 2016 by Captain Lockheed
More info

[Captain Lockheed]

Next I cleared the codes and started the car.

Recorded camshaft values at idle.

Idles is really smooth not lumpy at all.

[Captain Lockheed]

Doing a drive line check stops the engine.

 

[Captain Lockheed]

Voltage and current check, engine off ignition on.

 

[Captain Lockheed]

P0020 is back.

But not the visit workshop.

 

Edited November 28, 2016 by Captain Lockheed
More info

[Captain Lockheed]

Started the car and tried to monitor camshafts on bank 2 at idle and approx 3000revs.

 

[Captain Lockheed]

I note that post drive line check the idle camshaft values have changed. Idle is a wee bit lumpier but it is still really smooth.

Further info,

Oil pressure is good, top of the gauge when running, though I couldn't work out how to record that.

Oil is Mobil 1 0w-40.

Last service at 70,000 miles, current mileage 75,000.

All advice gratefully received.

[Ahsai]

Sounds like you have issues with the bank 2 variocam actuator or its circuit. The workshop manual should have the actual steps. I would expect testing of continuity of the wires between the actuator and the DME, ohm out the actuator, and also apply voltage to the actuator and listen for engine change. To diagnose this further, you will need a wiring diagram.

[JFP in PA]

You need to look at the cam position sensor in question on bank 2, which either is not sending a signal, or possibly an intermittent signal.  I would be looking at the wiring to that sensor as well, as a chaff or break can also cause this type of fault.

[Porschelibrarian]

I hope this helps...  

 

P0020
Position of crankshaft in relation to intake camshaft
F NOTE
This fault is entered if there is a permanent deviation from the nominal value of 10° camshaft angle.
Diagnostic conditions
D Battery positive voltage 10 ... 16 V
D Engine idling
D Camshaft adaptation has taken place
D No fault in camshaft sensor
D No fault in crankshaft sensor
Possible fault causes
E Camshaft sensor faulty (internal phase shift)
E Solenoid valve for camshaft adjustment soiled (does not close fully)
E Timing set incorrectly

 

 

 

P0021
Inlet camshaft control
F NOTE
This error is entered if the actual value varies from the target value by between 5° und 14° of the camshaft for a duration of 2 to 5 seconds.
Diagnostic conditions
D Battery voltage 10 ... 16V
D Time after engine starts > 30 seconds
D Engine and engine oil temperature -9°C ... 106°C
D Engine speed 1160 ... 6000 rpm
D No solenoid hydraulic valve final stage error
D No camshaft sensor or crankshaft sensor error
Possible fault causes
E Mechanical fault in solenoid hydraulic valve (sticks, sluggish, blocked)
E Dirt in the oil circuit
E Sealing strips on VarioCam adjuster faulty (leaky, sluggish)
E Oil pressure too low
E Mechanical fault in VarioCam adjuster
Page

[Captain Lockheed]

2 hours ago, Ahsai said:

Sounds like you have issues with the bank 2 variocam actuator or its circuit. The workshop manual should have the actual steps. I would expect testing of continuity of the wires between the actuator and the DME, ohm out the actuator, and also apply voltage to the actuator and listen for engine change. To diagnose this further, you will need a wiring diagram.

Thanks, I have a wiring diagram.

I am working on getting a workshop manual.

2 hours ago, JFP in PA said:

You need to look at the cam position sensor in question on bank 2, which either is not sending a signal, or possibly an intermittent signal.  I would be looking at the wiring to that sensor as well, as a chaff or break can also cause this type of fault.

Thanks.

48 minutes ago, Porschelibrarian said:

I hope this helps...  

 

P0020
Position of crankshaft in relation to intake camshaft
F NOTE
This fault is entered if there is a permanent deviation from the nominal value of 10° camshaft angle.
Diagnostic conditions
D Battery positive voltage 10 ... 16 V
D Engine idling
D Camshaft adaptation has taken place
D No fault in camshaft sensor
D No fault in crankshaft sensor
Possible fault causes
E Camshaft sensor faulty (internal phase shift)
E Solenoid valve for camshaft adjustment soiled (does not close fully)
E Timing set incorrectly

 

 

 

P0021
Inlet camshaft control
F NOTE
This error is entered if the actual value varies from the target value by between 5° und 14° of the camshaft for a duration of 2 to 5 seconds.
Diagnostic conditions
D Battery voltage 10 ... 16V
D Time after engine starts > 30 seconds
D Engine and engine oil temperature -9°C ... 106°C
D Engine speed 1160 ... 6000 rpm
D No solenoid hydraulic valve final stage error
D No camshaft sensor or crankshaft sensor error
Possible fault causes
E Mechanical fault in solenoid hydraulic valve (sticks, sluggish, blocked)
E Dirt in the oil circuit
E Sealing strips on VarioCam adjuster faulty (leaky, sluggish)
E Oil pressure too low
E Mechanical fault in VarioCam adjuster
Page

Thanks.

 

As all three have suggested I will look at the sensor and wiring

[Captain Lockheed]

Does any one know what the camshaft angles should be?

I am trying to pin down a workshop manual.

[Captain Lockheed]

I found this picture, I hope it is attached.

If it is I will be looking at 14 Camshaft sensor plug,18 Solenoid hydraulic Valve Plug Camshaft Timing 20  Solenoid Hydraulic valve Plug valve lift control and 22 Ground strap.

Edited November 29, 2016 by Loren
converted image to be viewable here

[Ahsai]

Your's a 997-1 so it should be very similar to 996.2 (variocam+). Check bank 2 and see if it looks like the second last photo in this post by John 

If so, the one on the left is the variocam timing (as opposed to lift) and that's the one you should be checking. The bank 2 cam sensor is toward the front of the car on the engine head.

 

The cam angle should be very close to what spec'ed angle (which varies per rpm) and the deviation from the spec'ed angle should be less than 10 degrees.

 

For WSM, check with porschelibrarian.

 

[Captain Lockheed]

Thanks, I will have a read of that thread.

[Captain Lockheed]

Am I right that ???

°KW = Korrektur Winkel = correction angle

 

[Ahsai]

I think it's crank angle (as opposed to cam angle).

[Captain Lockheed]

From the other thread gcp's figures at idle Actual 2.0, deviation 13.97, mine -0.4141, deviation -0.5000. And +/- 6.0° is OK?

I am going to try to work out how to record both banks on the PIWIS.

[Ahsai]

7 minutes ago, Captain Lockheed said:

From the other thread gcp's figures at idle Actual 2.0, deviation 13.97, mine -0.4141, deviation -0.5000. And +/- 6.0° is OK?

I am going to try to work out how to record both banks on the PIWIS.

 

Yes but your problem is at 3,000 rpm where the angle should switch but it didn't.

[Captain Lockheed]

3 minutes ago, Ahsai said:

Yes but your problem is at 3,000 rpm where the angle should switch but it didn't.

Thanks I am getting it now, I should really read stuff better. 

Approx 3000

Camshaft specified angle, bank 2 -16.7031°KW.

Actual camshaft angle, bank 2 0.6094°KW.

Camshaft deviation, bank 2 0.0000°KW

So on this example 17.3125° out

[Captain Lockheed]

Learning all the time at idle -0.0959° difference is OK.

[Ahsai]

Exactly and I suspect the reason why the deviation is shown as 0.0000 was because the system detected something is not operating properly.

[Captain Lockheed]

Or it isn't detecting a variance between two sensors and defaulting to zero. I am learning all the time, I just need to find the time to get under the car and look at the wiring. I wish I had a garage.

[Captain Lockheed]

I found this.

[JFP in PA]

1 hour ago, Captain Lockheed said:

I found this.

 

That is for the VarioCam which is a fixed change, yours is a VarioCam + system which has variable timing changes with engine RPM.