Wrench Blog


Other sites:

Mon Oct 03, 2005
Well, I've noticed a *lot* of hits coming from google lately in the access log for this site. Quite a few folks seem to be looking for info on Volkswagen camshaft position sensor problems. It's no surprise, really. Lots of people have problems relating to this sensor, and the online forums are full of posts by people looking for answers. My own experience with this sensor is on ABA engines, but as far as I know all of the VW 2.0 liter 8 valve Motronic engines use this sensor.

So, where is the camshaft position sensor and what does it do? The sensor is physically located within the body of the ignition distributor. It's electrical connector is on the outside of the distributor. The sensor feeds a signal back to the ECU (onboard computer). The name "camshaft position sensor" is kind of misleading. The computer uses the signal to determine the position of the camshaft; however, it does so on the assumption that the camshaft/intermediate shaft/crankshaft timing is 100% correct. To elaborate, the ignition distributor is directly driven by the intermediate shaft. The intermediate shaft is driven by the timing belt, which also drives the camshaft and the crankshaft. This means that the computer can calculate the position of the camshaft by knowing the position of the ignition distributor. The camshaft position sensor is actually a hall sensor (hall sender) that sends a signal once per revolution of the distributor. One revolution of the distributor equals one revolution of the intermediate shaft, which equals one revolution of the camshaft. So that's why it's called the camshaft position sensor when it actually lives in the distributor.

So, why do so many people have problems with this critter? So many people have problems because they have timing belts replaced by people who don't appreciate how much the whole system relies on the timing between the camshaft, intermediate shaft, and crankshaft being absolutely correct. The ECU has enough input from other sensors on the vehicle to tell if the intermediate shaft is off by as little as one tooth. The DTC (Diagnostic Trouble Code, or Fault Code) that usually plagues VW owners is "Implausible Signal". That means that the ECU has detected that the signal from the camshaft position sensor cannot possibly be correct, based on other feedback from the engine. If your timing is off by a tooth, then this is the message you will get.

So, is that it? My timing is just off? Well, not necessarily. If you have the "Implausible Signal" code stored, then it's probably your timing. However, you may have a different message stating that the signal is either open or shorted to ground. If you have such a message, then timing is not the problem (at least, timing isn't the *only* problem). This is the message you will see if the sensor is faulty (or disconnected); however, it could also indicate a wiring problem. Don't replace the sensor until you have thoroughly checked the wiring between the sensor and the ECU. Using a multimeter, check for open circuits, and also check for continuity between the signal wire and ground (there shouldn't be any!).

I think it's my timing! What should I do? If you had the timing belt installed by someone else, then hopefully it was a VW specialist who will readily admit their mistake and correct it. If you took it to an ordinary shop. then you'll likely have a hard time with that... and they'll probably even try to charge you so they can replace the sensor that is almost certainly still fine. If you're the one who did the timing, then re-do it until you get it right. I rarely get it right on the first try. so don't feel too bad. You must follow the procedure in the Bentley manual exactly as they say. And make sure you are following the procedure for the correct engine. On many of the newer VW engines, such as the ABA engines, the marks on the v-belt pulleys are no longer used for timing. For these engines, the mark on the camshaft sprocket gets aligned with a mark on the inner portion of the plastic timing belt cover, the crankshaft gets aligned so that the #1 cylinder is at TDC (top-dead-center) (which can be done by lining up the TDC mark on the flywheel with the "pointer" mark on the inside of the timing hole in the transmission bellhousing), and the intermediate shaft must be positioned so that the ignition rotor points directly to the mark on the distributor housing. Consult the Bentley manual for details, and pictures. *DO NOT* attempt any of this unless you know what you are doing. Seriously, you can damage the engine internals (valves/pistons) otherwise. I take no responsibility for any damage you cause. Many, many people have this problem after having a timing belt replaced. If you are going to have the belt replaced, I highly recommend you have it done by a VW/Audi specialist. It will be more expensive, but they'll be far more likely to get it right.

Yikes, that's a lot of info! Yes, it is - but that's not all of it. I recently bought an A3 Golf with this problem, only it was caused by something a little different. The previous owner had swapped around all of the plug wires so that the firing order was still correct; however, the plug wire for the #1 cylinder was no longer plugged into it's correct location. Basically, the wire positioning was "rotated" a little bit. The ECU *requires* that the plug wires be installed in their correct locations (#1 wire gets plugged in closest to the timing mark on the distributor body). Otherwise, the ECU will think that one cylinder is firing when another is firing. The car will still run, but you will never get rid of that code and the check engine light will stay on. So, if you've recently replaced your plug wires (or had someone else do it), make sure to check that they are installed correctly.

I apologize for this long and tedious post, but it's my hope that somebody will find it useful. I will try to periodically do a post like this, where I address issues that I can see people are searching for.

377 views 25 comments, click here to view them!

Post your comments below. Please note that your comments will not be visible until they have been approved by a moderator (me).
Your name:
E-mail address or website URL:
Your comments:
Captcha response: testing

Date: 08/24/06, 13:31:02 PDT
From: Kelvyn
Comments: Many thanks for taking the time to write that very useful info! FYI, I was looking for help on the same problem but a different VAG car (P0341 fault code on a Skoda Octavia).

Date: 07/17/07, 13:22:55 PDT
From: Filip
Comments: hi, its really very usefull, but I get 0300 code - "no signal" what you thing the problem is? many thanks

Date: 10/20/07, 05:28:54 PDT
From: Paul Howard
Comments: Excellent information. This is exactly what I needed to know. Thank you very much!

Date: 03/06/08, 14:04:55 PST
From: Ludmil Drankarov
Comments: I have recently rebuilt 2001 VWPassat 1.8 T AUG engine due to heavy sludge. Most of the job was done on the head and upper end. I did not take apart the lower end. Now I am getting rough idle at 760-1500RPMs and P1340/cam pos. sensor and crank speed sensor incorrect correlation/, random misfires on all 4 cylinders the RPM range above. Do not have misfires at RPMs above 2000. I did check twice timing belt alignment and it is perfect. Have not checked cam shafts timing, but for sure it is set 16 chain rollers apart. Do not believe bad cam pos. sensor, because the engine runs fine at high RPM. Any Ideas what part may cause P1340 code to show up at low rpms?

Date: 03/17/08, 16:03:57 PDT
From: mark hunter
Comments: after reading your post Im a bit worried, My vr6 b4 will only run for a few min. obd2 code comes up cam shaft position sensor, Is it going to help if I replace it????

Date: 04/15/08, 01:21:23 PDT
Comments: I have intermitant spark from the coil. new coil, new distributor cap, new computer, I have heard the crank position sensor may be the problem. Any suggestions. Thanks in advance.

Date: 06/12/08, 09:35:48 PDT
From: Dave
Comments: Thanks for excellent information on the position of the intermeiate pulley. This is the first 2.0 ABA I have worked on in my 53 years, and items like this could trip up an otherwise good job. The coolant hoses on this motor are VERY unique.

Date: 06/24/08, 15:45:30 PDT
From: andy
Comments: Thanks very much for the information. My 6N2 VW Polo GTI gives the same error code, and as a result will not activate the VVT actuator. I am going to look into your suggestions ASAP. Cheers Andy

Date: 07/03/08, 22:35:57 PDT
From: Simon
Comments: Very useful info this! Do you have any experiance with AUQ 1.8litre 20v turbo engines? I am in the UK and having similar probs with mine in a 2003 Skoda Octavia VRS. Have just replaced the cambelt and was convinced the timing is correct, but have the P0341 code. Regards Simon

Date: 02/05/09, 15:22:32 PST
From: matthew ebersole
Comments: I have the same problem in my 98 Passat 2.8; engine code 1519, Intake Camshaft Control Bank 1 Malfunction. I get a very loud "clicking" sound coming from the right side of the engine, which seems to make the noise every revolution. I'm wondering what I can do to isolate the problem, and hopefully fix it myself. Thanks, Matt.

Date: 02/08/09, 18:24:31 PST
From: Max
Comments: Hi Matt, Sounds like you may have timing chain issues - as the chain tensioners/guides fail, slack develops causing noise and sometimes even slipping teeth. Both your noise and your engine fault code could be caused by timing chain slack. If you've never done a timing belt or timing chain replacement on an interference engine, then make sure this is something you really want to attempt yourself. If you have an aptitude for mechanics, then you should be fine with the proper documentation - if not, then you may want to reconsider doing this yourself.

Date: 02/21/09, 14:15:57 PST
From: Roger Veilleux
Comments: I liked your post very much.I like to work on cars and I had a custmer with the engin light on and i got the code for the cam shaft postioner a . and she sead the light dident come on untell she had the timing belt changed. so im going to say you are right on the money. Thank you for your input. bikerroger@gmail.com

Date: 03/10/09, 06:07:13 PDT
From: Gerald
Comments: Hi I have camshaft hall sensor which is faulty on my car (2002 GOLF 4 1.6). Please can you forward me a schematic diagram of the sensor and the electronic components used so that I can try to repair mine. The part no is 06A 905 161 B(Bosch). Any help will be much appreciated. Thank You Gerald South Africa

Date: 07/23/09, 21:31:17 PDT
From: Night Hawk
Comments: Your tediuos efforts just made my two+ year cam position sensor problem become a quick savings of atleast from the dealer. Yeah they charge an arm and a leg for it. Thank you o so very much fellow V-Dubber!

Date: 07/29/09, 14:48:17 PDT
From: joseph
Comments: This has been very helpful to me. I just bought a 2001 Passat GLX for my son. Timing belt was changed about 15000 miles ago and car just stops sometimes for no reason and will not start. You can then try to start maybe about 30 minutes after and it starts like a charm like nothing ever happened. Mechanic has narrowed it down to this. Joseph

Date: 08/02/09, 16:01:59 PDT
From: Vince
Comments: HELP HELP HELP... I just replace a timing belt for 99 Passat and now I'm getting two codes P1519 & P1522, I belive that my timing belt was set correct but If I need to make adjustement how can I do this?

Date: 08/14/09, 13:02:19 PDT
From: nick bridi

Date: 04/08/10, 09:42:41 PDT
From: Andrew
Comments: THANK YOU whoever you are. Finally someone who knows what they are talking about

Date: 07/20/10, 13:56:06 PDT
From: chris
Comments: Hey, Your not going to believe this. Went to VW last year, they replaced the timing belt. Last week, timing belt was off and I had to pay for adjusment and the 100,000 mile check up. This week the senor went bad and they wanted to charge me . I read them the stuff off of here and they are doing it for free. Not bad for a gurl !

Date: 01/31/11, 01:28:07 PST
From: Daniel
Comments: Thank you somuch for your detailed comments on camshaft position sensor. I found it very useful. God bless!

Date: 10/10/11, 01:35:31 PDT
From: Ling bur
Comments: Thanks for your detailed explanation. Very useful, VW dealer changed my camshaft belt and 5 mths later the engin light comes on intermittently. RAC says it's a crank sensor problem. I'll be taking it back to VW for a check this week pointing out that it could be there error.

Date: 10/16/11, 13:36:42 PDT
From: Cody
Comments: I just had to replace the water pump on my 1996 VW jetta and in order to get it off the engine i had to remove the distributor pully that is connected to the timing system. I got everything all put back together and we started the ca . lucily we had everything in time for the most part. but the check engine light is on and i plugged the code reader deal in and it told me it was the crankshaft positon sensor so it has to be off by only one tooth because the car runs good just when you first start it up and step on the gas it has a miss. but other than that it runs just like it always did. so tomorrow we are going to replace the timing belt and reposition the camshaft pully.. but i just wanna know if it will mess up the motor if i drive the car while the camshaft isnt in time.

Date: 06/04/15, 23:10:42 PDT
From: Gabriel
Comments: My Mk5 R32 Has Two sensors..... So i have impulse on The first three cylinders and nothing on cylinder 4 5 and six... Somebody temperd with the cam belt.... swapped the sensors.... but i still dont get any impulse on cylinder 4 5 nd 6 connector plugs on the coils.... Cars misfires bad....i need help

Date: 11/16/15, 22:33:20 PST
From: neil
Comments: Hi,we are having trouble with a jetta5. 1.9tdi bxe. When the vehicle was towed in the customer reported that,it just cut off while driving,and didn't want to start after. We did a few tests,like checking if the diesel pump,and soforth were working,and found that it was in order. Then we got to the can belt and found that the belt hadn't snapped. We then changed the can sensor and tried to start but it wouldn't. We then tried abit of quick start into the a.f housing,it started but wouldn't idle. We then removed the gearbox,flywheel,and found that the pickup ring on the sensor had oil on it. We then removed the seal and ring,cleaned it,put the ring on its mark,including the mark on the front pulley. Closed it up,and double checked our timing on the can before starting. It started,but sounded abit rough,so we set the cam to fire on no 4 and we started. It started with one swing and sounded great.when we rev we could hear the turbo,but this is where the trouble started. We took it for a test drive, I think it was less than 30min. As we came to a hill it couldn't go up,and it cut off. And refused start. So we decided to get a new rear main seal and fitted it. Now it just won't start,and all is on timing. What could be wrong now?????

Date: 11/29/15, 20:27:34 PST
From: ChrisD
Comments: I have bought 2001 1.8l Passat and the code cam up for camshaft so I replaced it firs thing. The light cam back so I checked the wiring for continuity and volts, it all checked out good. I event took the sensor out plugged it in and ran my screwdriver between the magnets and watched the volts brake on the center wire, and all that checked out. Next I checked the time and it was off by half a tooth so I did the timing belt, pump ect.. The timing marks are perfect and the sensor still come up. I double checked the first cylinder piston TDC with the mark and it's perfect. FYI for whatever I have done that car behaves the sam as it was before. On a cold start up it don't idle properly for about a 30 sec. that its, eve if I clear the codes night before. What is the next thing should I check? Should I replace the chain and tensioner? Thanks a lot your info is great.
A1 parts for sale:
intake air preheater hose
Item: Intake air pre-heat hose (from exhaust manifold shroud to air box), for Scirocco 2 (1982+)
Condition: New

A2 parts for sale:
A2 GTI dual round grill, with inner lights
Item: GTI dual-round grille with inner lights, bulbs, and lower trim strip
Condition: Used, lower trim strip is weathered.

parcel shelf strap
Item: Parcel shelf strap, 3 available
Condition: New
$3.50 ea.

A2 valve guides, 8 valve
Item: 8 (eight) valve guides, German, standard size, for 8 valve head
Condition: New

wheel cylinder
Item: Wheel cylinder (for rear drums, obviously), 2 available.
Condition: New
$12 ea.

A3 parts for sale:
parcel shelf strap
Item: Parcel shelf strap, 3 available
Condition: New
$3.50 ea.

A4 parts for sale:
ALH water pump
Item: OEM Water pump, ALH engines
Condition: Used, 130,000 miles