Camshaft Position Sensor P0340 P0341

[dshelton0504]

My '04 Jetta 1.8T currently has CEL on. Codes P0340 & P0341 show up. I replaced the camshaft position sensor and disconnected the battery to delete the codes. CEL went off but after a short drive came back on (same Pcodes). I've noticed the fit between the CPS and the wiring harness isn't real crisp but it has a locking clip so I assume the fit is normal.

A little background... Timing belt broke in October and bent 12 valves. I had the head rebuilt and installed new belts, tensioner, idler, H2O pump, etc. Fired it up and CPS Pcodes were there. The engine runs and idles beautiful. Normally the car fires right off but every once in awhile the car starts hard (3 cranks on the ignition).

Any ideas? Is it possible the timing belt is off a tooth? Seems that it would run rough if the belt was off.

[White Jetta]

A common problem on these engines is setting the new timing belt off one tooth, happens frequently. Cam sprocket needs to be turned back/left one tooth usually.

There are threads about his in the 1.8T engine forum, look for the Timing Belt DIY master thread with over a dozen pages.

[CorradoG602]

Quote, originally posted by dshelton0504 »

Is it possible the timing belt is off a tooth? Seems that it would run rough if the belt was off.

Yeah check the timing, but if the timing is off it would usually give you a cam over advanced or cam timing retarded. It can happen when off half a tooth

P0340 Camshaft Position Sensor -G40- Circuit Incorrect allocation.
P0341 Camshaft Position (CMP) sensor -G40- implausible signal

Check the bolt for the shutter wheel and see if thats tight. You replaced the cam position sensor so rule that out. See if the shutter wheel is on the right way. Remove the harness connector from the sensor and turn the ignition on. measure the voltage of the 3 pin connector. Brown is ground obviously. You should get a min of 4.5 V with the key on. If not remove the ECM and do some resistance tests.


Modified by CorradoG602 at 5:33 PM 2-1-2010

[dshelton0504]

Is the shutter wheel the slotted wheel attached to the camshaft under the CPS? If so, I removed the wheel yesterday to double-check I had it properly installed. There is a key on the wheel so it can only go on one way (thankfully) It did not appear to be loose before I removed it as I had initially torqued it to spec.

I'll double-check the voltage on the 3-pin connector.

[dshelton0504]

I'll check out the threads on the engine forum. Interesting that it shouold be turned back/left one tooth.

When I installed the belt I noticed the cam gear was at TDC but the crankshaft mark was slightly (1/8") to right of TDC. I monkeyed with turning it back to the left but the crank mark was off about 1/4" in that position so I set it back to right of the mark.

[CorradoG602]

The easiest way to always be on time when you do a t belt on a 1.8T......put the belt on the crank and water pump first so half the belt thickness wise are on those, leave the tensioner loose with no nut on the bolt or whatever it is. With your right hand on the crank hold the belt there stretch the belt up making it tight but not tight enough to move the crank with your left hand. take your right hand off the crank and grab a 16mm box wrench while still holding the belt tight with your left hand. put the wrench on the cam sprocket bolt and rotate the cam toward the front of the car until the belt can go on and put it on. This will keep the front portion of the belt tight and you can work the back half of the belt on easily. get everything set and tight, pull the pin and rotate it once over, the timing will be dead on every time.

[dshelton0504]

Pulled the TB covers off again and checked the belt alignment. Crank pulley is aligned perfectly with the lower belt cover mark at TDC. The cam gear is dead on the mark on the valve cover. The car has been idling perfectly and running without misfire.

You still think I need to adjust the belt by a tooth?

[BooneGLI]

Any update on this issue? I got a P0340 after I did my T-belt and I am positive that the belt is on correctly. Thanks.

[Brattt]

Same issue here!!!

[whitemkiiigti]

I have just got the same p0341 code in my 98 gti with the 2.0L I did not do a timing belt it just kicked the code and check engine light. The car is running fine, but it is going to be emissions time soon and as we all know it wont pass with the light on. The sensor is part of the distributor right. Am I looking at a new distributor or can the sensor be replaced seperate. Any help would be great

[whitemkiiigti]

Sorry guys i got on the wrong part of the forum. I saw another p0341 code post on a mk3 page.