# Camshaft Position Sensor - Implausible Signal



## bobsled (Aug 25, 2006)

I did search, and found a ton of info, but nothing that really relates exactly to what is going on here.
Symptoms: 
Jumpy idle when coming to a stop. - idle will jump from about 500-1000 until the car is completely at a stop. Steady's out once at a complete stop. Happens in neutral and in gear with clutch depressed.
Only get a check engine light when starting car, once running, if code is cleared, it will not show up again until stating again. That is also the only code I have.
Car drives fine, no loss of power.
Car needs t-stat, cat, and possibly plugs replaced. Any relation to sensor issue?
Checked timing, and it looks fine, belt is still in great condition, I changed it about 20k miles ago. Tension seems good.
Tried cleaning the plug for the sensor which didn't help.
Is the sensor just bad? I've read on mk3's that sometimes the sensor need to be looking through one of the windows when it starts or it will throw a code, but that is a totally different sensor iirc.
Trying to explore any easier options before i try to tear apart the head to replace this thing... 
and it is a 1999.5 aeg, head has never been removed, not cammed.
thanks in advance for any help


_Modified by bobsled at 11:01 AM 1-20-2009_


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## zero. (Aug 14, 2001)

*Re: Camshaft Position Sensor - Implausible Signal (bobsled)*

If you are getting that code it's almost always related to timing. Usually it's the ignition timing that's off. I'd check all timing marks. You could check the sensor with a voltmeter too, but not sure on the readings you should be getting.


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## mrdub27 (Mar 25, 2002)

*Re: Camshaft Position Sensor - Implausible Signal (bobsled)*

tried cleaning the TB yet .?? hmmmmm


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## bobsled (Aug 25, 2006)

Thanks... i guess ill look at it again.
Today the car has barely been able to idle, if i take it out of gear from about 3k rpm or higher, the car will just drop down to 0rpm and stall. And the car will barely idle above 600rpm.
The only difference between today and yesterday is that some evap codes were cleared and I had cruise control added back onto my ecu. 
It was jumpy at idle before this, but never to the point that it stalled, and it would eventually regain itself and idle at 850rpm once at a complete stop.
Now it can barely idle above 600 and just seems like something is really wrong until it starts driving


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## bobsled (Aug 25, 2006)

*Re: Camshaft Position Sensor - Implausible Signal (mrdub27)*


_Quote, originally posted by *mrdub27* »_tried cleaning the TB yet .?? hmmmmm

yeah the tb was cleaned no more then 3k miles ago along with the entire intake mani.


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## bobsled (Aug 25, 2006)

So I'm not sure if my timing is perfect...
I guess I will take the belt of and try to line it up but i just dont see how it could have jumped a tooth. And if that was the case I cannot understand why the idle situation only got worse after the ecu reflash (which actually removed some codes that shouldn't have been there). 
Car is running worse and worse the more I drive it... it keeps trying to idle right above 500 rpm if it doesnt just stall (ahh)...
Everything I have read about Camshaft position sensor DTC's, has been a timing issue...but none of them were for "Implausible Signal". Which makes me think it is an issue with the sensor or something else electrical... any more insight from anyone?


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## 2LTurbo (Aug 26, 2008)

my sensor broke and cause the same DTC, you could see it dangleing in the cam sprocket.. never had a prob running other then crappy vaccum on startup. still driving with it fine to this day


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## bobsled (Aug 25, 2006)

*Re: (2LTurbo)*


_Quote, originally posted by *2LTurbo* »_my sensor broke and cause the same DTC, you could see it dangleing in the cam sprocket.. never had a prob running other then crappy vaccum on startup. still driving with it fine to this day

hmmm
so if your car is running fine without it, that means my timing is probably off. fuuuucccckkk
not the kind of job i wanna do in 10*F in the snow.


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## bobsled (Aug 25, 2006)

so when I unplug the sensor, the car has trouble starting, but idles perfectly haha.
I will take it for a drive around the block without the sensor in later...
this will put the car in limp mode and use a ton of gas right?


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## zero. (Aug 14, 2001)

*Re: (bobsled)*

You should double check that it's the sensor that is actually shot and not just the timing off. With the sensor not hooked up or broken, performance will be affected. Not sure if it's limp mode or not, but I'm pretty sure it retards the ignition timing.


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