Intake Cam Actuator Solenoid

Michael Owner/Technician Quakertown, Pennsylvania Posted   Latest   Edited  
Case Study
Electrical
2011 Volkswagen Routan S 3.6L (G CJRA) 6-spd (62TE)
P0010 — "A" Camshaft Position Actuator "A" Control Circuit/Open Bank 1

CEL on with the P0010. Engine running fine at the moment and oil level and condition are perfect. Took a quick look without any disassembly at the actuator solenoid and didn't see anything obvious. I got a wiring diagram and saw it had a constant ground which told me it was power side switched. Hooked a test light to B+ and the other end at the control wire of the bank 1 intake cam actuator solenoid (back probed with a T pin) and bidirectionally commanded the solenoid to pulse to 20% then 40% then 60% and kept it at 60% and saw the test light was not illuminated at any time.

I did the same test on the bank 2 intake solenoid (known good) and the test light lit and got more dim as the pulse width changed so that tells me the PCM has good control of it. I then removed the air intake tube to get better access to bank 1. 

Fired the scope up and probed the control wires at bank 1 and 2 intake cam to compare a known good. Immediately saw something weird on the waveform on bank 1 AND the test light now lit... But it didn't before so why am I seeing a "decent" looking waveform (blue trace) It's not great but there's something there. So, I have better access to the connector now and notice the power steering return hose is laying on the wiring pretty tightly. I move the hose and then I get a good looking waveform (much like bank 2 - green trace) Fiddled with the wiring a bit near the connector and my bank 1 waveform is dropping out as i'm wiggling the wiring. The return hose, over time caused the wiring to stress causing a poor connection. I am confident that a new pigtail and securing the hose better will be a fix on this one. 

This may not be one of those head scratchers but I feel my diagnostic direction was good here as that is a weakness of mine. Hope this helps someone! 

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Phillip Technician
LaVergne, Tennessee
Phillip Default
 

Thanks, this helps me. Sometimes it is the small thing's that trip us up.

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Joe Technician
Benicia, California
Joe Default
 

Nice study! It pays to pay attention to what you are doing/have done when waveforms change like that. Great info

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David Mechanic
Stockport, United Kingdom
David Default
 

Hi Michael, help me please , you say the actuator is power side switched and has a perminent ground. Yet the test light was connected to battery + , is this a typo or am I missing something ? Please don’t take this as me trying to pull you up it’s because I want to learn . Kind regards Dave T.... 🇻

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Michael Owner/Technician
Quakertown, Pennsylvania
Michael Default
 

Yes, David. The solenoid is power side switched which means you need a power feed to control it. The PCM in this case supplies a power feed to the solenoid. Having one end of the test light on battery positive and the other end of the test light touching the control wire of the solenoid while commanding the solenoid to pulse allowed me to "be the computer" by verifying the test light would light.

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David Mechanic
Stockport, United Kingdom
David Default
 

Thanks Michael for taking the time to explain ! So you are using the test light as a computer safe jumper lead and the bulb lights through the solenoid earth return. Once again thanks ! Kind regards Dave T...

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Michael Owner/Technician
Quakertown, Pennsylvania
Michael Default
 

Sure thing!

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Stuart Mobile Technician
Blue Island, Illinois
Stuart Default
 

Thanks for sharing.I have seen this type of issue several times in my years​.​Unfortunately we have to do so much disassembly these days just to get access just to diagnose in similar cases.

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