camshaft position sensor

hgsmith

Veteran Member
Joined
Sep 19, 2008
Location
TAFT, TN
TDI
2003 Jetta
I have a G40 Vagcom code,16705, P0321, which shows an intermittent Signal to the Camshaft Position Sensor. The glow plug light and the engine light came on. The Jetta is a 2003 auto with 243,000 miles on it. It runs fine at highway speeds, but the engine will cut off at slower speeds. The replacement looks fairly easy. My question is can I unplug the sensor until a replacement arrives and still drive the car ?
 
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DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Your car does not have a camshaft position sensor.

That code is for the crankshaft position sensor, G28.

http://wiki.ross-tech.com/wiki/index.php/16705/P0321/000801

The Ross-Tech document mentions a TSI 2007067 regarding electromagnetic interference. I have not found a copy of this TSI.

I have found bad wiring issues on the crank sensor causing problems. Replacing the sensor or repairing the wiring pigtail on the crank sensor fixed it. Rarely the sensor wheel inside the crankcase comes loose.

From the tech brief on this engine:
Engine speed as determined by G28
The engine speed is one of the main factors which the
control unit processes in order to calculate the injection
quantity.
Substitute function
If the engine speed sender is faulty, an emergency running
program is activated. The needle lift sender G80
supplies a substitute engine speed signal for this purpose.
The injection quantity is reduced, the commencement of
fuel injection is controlled and the charge pressure control
is switched off during emergency operation.
If the substitute engine speed signal of G80 fails as well,
the engine is turned off.​

I would expect severe performance reduction is in this limp home emergency running mode.

There are also posts that indicate you can get this code due to fuel delivery problems. It is not clear, but these posts may have been for a PD engine. By the way, a BEW PD will not run with this sensor unplugged, but a BRM PD engine will (this is of no import to your engine - just a note for future searchers.)

If the engine has fuel delivery issues then unplugging the crank sensor will obviously not help.
 

hgsmith

Veteran Member
Joined
Sep 19, 2008
Location
TAFT, TN
TDI
2003 Jetta
Thanks, Dan you are correct. It is a crankshaft not camshaft problem. I wrote this late last night with only 4 hours of sleep. I did drive it home with no problems, 120 miles. It seems to do better if t it has sat for 6 to 8 hours. How do I check the wiring ? I suppose for continuity ? Should all wires show be zero ?................. How do I change the title to crankshaft ?
 
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jcrews

Top Post Dawg
Joined
Jul 28, 2007
Location
Round Rock, TX - VCDS
TDI
All gone
Check address 17 and 19 for Engine control module -- no communications --intermittent.

It might be a ghost code thrown by a power dropout (bad supply relay #109).

If it's not, check the wire from the sender to the 3 pin connector near injector #3.
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Since the problem is intermittent, just wiggle the wiring while running the engine. See if the problem comes and goes - or comes and stays.

Plug and unplug the sensor connector (on the front of the engine), and then replug it in several times. If the problem is there, it may show up.

On the sensor pigtail the resistance between pins 1 and 2 is 440 ohms. All other resistances are greater than my Fluke could measure. Polarity changes did not alter the readings.
 
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hgsmith

Veteran Member
Joined
Sep 19, 2008
Location
TAFT, TN
TDI
2003 Jetta
wiggled the wire around but the car never died. Will try the vcds as soon as the battery on the computer is charged.
 

hgsmith

Veteran Member
Joined
Sep 19, 2008
Location
TAFT, TN
TDI
2003 Jetta
replaced the crankshaft position sensor and everything is running great. No more problems with the engine shutting down.
 

jzacher85

New member
Joined
Oct 26, 2010
Location
Colorado
TDI
2004 Jetta Wagon
I just got my car back from the dealership and they said that I needed ro replace the crankshaft position sensor because my car is not starting in the cold weather. They did the reflash and glow plug update. I purchased the sensor and have to replace it but I do not know where the sensor is located. could anyone describe or give a rough drawing. the car was dropped off at a worker for the dealership's house and it has been cold so I can not get the car back until I replace the sensor, if that fixes it that is. Is it easy to replace?
Thanks in advance!
-Jesse
 

jcrews

Top Post Dawg
Joined
Jul 28, 2007
Location
Round Rock, TX - VCDS
TDI
All gone
The crankshaft position/engine speed sensor is mounted on the side of the block, near the transmission. It's the side you can easily see from the front of the vehicle.

If you're getting a fault code for the sensor, make sure it has clean contact with the block, the wires are OK, and the sensor itself is clean.

Otherwise, start by making sure the tank pump works.
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
The crank sensor is easy to replace, you need a 12 pt 9mm or 10 mm socket (I cannot remember which), it is a bolt on component.

It does seem odd that they would come up with this diagnosis.

I have never heard of a temperature sensitive crank position (speed) sensor.
 

PDJetta

Top Post Dawg
Joined
Nov 6, 2003
Location
Northern Virginia
TDI
'04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
I thought they'd throw a code if bad and if not, they were OK.

Yes, check the lift pump.

Since you got the sensor, put it on and let us know if it starts any better.

--Nate
 

hgsmith

Veteran Member
Joined
Sep 19, 2008
Location
TAFT, TN
TDI
2003 Jetta
It's a 9mm 12 pt. I had to use a closed wrench which took longer than I would have liked. Its on the drivers side on the block and it plugs into the harness that is just below the number 3 injector. You can do it from the front of the car on top, no need to do it from underneath. Mine did throw a code and the glow plug light came on.
 

jzacher85

New member
Joined
Oct 26, 2010
Location
Colorado
TDI
2004 Jetta Wagon
Installed the senor and it started this morning when it was 3 degrees F. I went through the whole glowplug recall ordeal only for the to think (after many months of bullcrap) that it was a sensor. They wanted 400 to do the sensor so I said no and took it home.
I replaced glow plugs and had it reflashed. less than a month ago. I was getting dash warning lights for glow plugs and engine.
If someone is having issues with cold temp starting maybe they should check their crank position sensor?
Thanks for the help!
Jesse
 

boiler01

Member
Joined
Feb 4, 2009
Location
Lafayette, IN
TDI
01' Jetta, 99.5 Jetta
I am getting both the glow plug relay code and crank position sensor code. I haven't had any problem with it starting until 2 days ago when it got into the single digits and wouldn't start. Going to replace the CPS today and see what happens.
 
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