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Discussion Starter #1
Son has a hi mileage GTI VR6 but had regular service records.It had a CEL with P0016 code but it ran pretty good. He has had to drive it for a while. Now after driving about 20 miles it will cut off. It will crank but not start. If you leave it sit for a couple of hours it starts fine and runs good for another 15-20 miles. One time it did it the EPC light came on. Left it parked for a while and came back. Restarted and drove fine no ECP light. Had the codes read and now it has a P0018 along with the P0016. Don't know if the P0018 is new or happened recently as the CEL has been on a while. The codes reference the cam position sensors. In everybody's experience on here what are the chances that new sensors would correct the problem? I know with my luck it probalbly needs a new timing chain but that probably won't happen. I am a pretty good mechanic but changing the chain on this thing is really extensive and requires special holding fixtures, is this correct? Having it done is out of my price range. Thanks for any advice

Thanks

Ed
 

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this is exactly what the code means, from rosstech wiki.

16400/P0016/000022 - Bank 1: Camshaft Position Sensor (G40) / Engine Speed Sensor (G28 ) : Incorrect Correlation

Possible Symptoms
Malfunction Indicator Light (MIL) ON

Possible Causes
Timing Issue
Camshaft Adjuster

Possible Solutions
Check Setting of Timing Belt
Check Timing of Intake/Exhaust Cams
Check Cam Adjusters as per Repair Manual

Special Notes
When found in 2009 Audi A4, A5 or Q5 with 3.2FSI AVE Engines, please see TSB 15-09-04.
On engines with chain driven intake camshaft(s), but belt driven exhaust camshaft(s), verify the number of chain roller links between the intake and exhaust camshafts is correct.

heres the link to the page, it has a diagram that might help at the bottom:
16400/P0016/000022 - Ross-Tech Wiki
 

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Discussion Starter #3
Thanks for the info. Is it a major disassembly to check the links in the chain? Any hints or links on How To? Since it runs really well when it starts, I wouldn't think that is the issue. I would think it would run crappy if the chain got the cams out of sync. Do you agree?

Ed
 

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Discussion Starter #4
Until I get the manual, could someone tell me where the Vehicle speed sensor is on the 2.8 VR6? I am a little confused between that and the crank position sensor. Thanks.

ED
 

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Cams sensor is a really common problem. They go bad.

Cams out of sync would be belt or in your case chains/guides. Timing components should be changed out at every 100k on a vr6 so you don't ruin your head.
If the cams were out of sync you would have just that, a ruined head because it's an interference motor and those valves will bend right now.
If you had a ruined head the car would never run well, always poorly or fail to start at all. You would also likely hear nice noises.

For speed sensor, it's on the back of the hub. Pull the wheel, look for some wires on the hub, two of them go into a plastic clip sensor. There's your sensor.
 

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Discussion Starter #6
Thanks Shameless,

I thought the speed sensors on the wheels were for the ABS system. I have others say the Vehicle Speed Sensor and the Crank Position Sensor are the same sensor and some say they are separate sensors. I am a little confused. Not a whole lot of info for the 2.8 24v with manual transmission out there.

Ed
 

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Crank measures the RPM.
ABS measures the speed.

You figure, for the crank to figure out RPM it would need the computer to tell it what gear it is in and then do different formulas to get the amount in real time. Where as a wheel sensor just says this many spins = this speed, wham bam done.
The abs does do the vehicle speed collectively, then when one of them is completely stopped or stopping too fast then it pumps the abs. It kind of needs to be measuring the speed of the vehicle to begin with so might as well use it as dual function.
 

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Discussion Starter #8
Thanks Shameless,

I guess I will try the crank sensor first and see what happens. That is the sensor by the oil filter correct?

Ed
 

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Discussion Starter #9
Sorry about the long delay but I just noticed I never responded to my post. We changed the crank sensor and car has run great ever since so the crank sensor was definately bad.
 
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