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Variable Cam Timing Malfunction in 2003 NB

PostPosted: Sun Dec 19, 2021 5:38 pm
by SteveL
The check engine light on my 2003 NB came on and my OBD2 scanner gave a code that says that the intake cam variable timing system is malfunctioning. The intake cam timing isn't advancing properly. This problem is a new one on me.

The first thing that comes to mind is failure of the solenoid. Does anyone know whether it's possible to diagnose the specific causes for the failure of my variable timing malfunction? Is there a way to test the solenoid? Is there a way to test other parts of the system? Would a repair shop have better diagnostic tools to identify different components of the cam timing system?

I appreciate the wisdom of those who are smarter than me. What are your thoughts?

Re: Variable Cam Timing Malfunction in 2003 NB

PostPosted: Thu Jan 13, 2022 6:25 am
by SteveL
I guess that nobody had any wisdom to share about the Variable Valve Timing malfunction. So I will answer my own question...kind of.

The Variable Valve Timing in 2001-2005 NBs is partially electronic and partly based upon oil pressure. I still don't know how to diagnose which part of the system has malfunctioned. According to the diagnostic decision tree, the timing belt might be the problem, but I installed that 5 years ago and the car has run well ever since. So I will look at that last.

The two areas where I plan to begin are the oil control valve and the solenoid, which is the electrical unit bolted to the oil control valve. The oil control valve is bolted on the top of the valve cover. It contains a screen filter and numerous parts that have O rings. My first step will be to rehab. the oil control valve with a new set of O rings and filter. This rebuild kit is NOT available thru Good-Win. You can find directions on how to do this job on You Tube. Like everything else on an NB, it's a simple job. I am told that you can test the solenoid using an ohm meter. But if servicing the oil control valve doesn't work, I will move to the solenoid. The solenoid is NOT available through Good-Win Racing either. My timing belt is due for change later this year, so checking timing marks and replacing the belt is also in the plan.

It's bitter cold in my part of the country and my pretty NB sits in the back of my shop until Spring. That's when work will be done.