'03 TDI cam shaft position sensor

[03_blue_jetta]

Hi guys - new to the forum, but wondering if I can get pointed in the right direction.

I was driving on a medium speed road (80km/h or 50mph) and my 2003 Jetta TDI engine cut out. Very smoothly, no loud noises or strange vibrations. Just no RPMs. I hit the clutch while coasting along and restarted the engine. It ran only briefly then cut out again. This repeated maybe two or three more times until it just wouldn't start. My first thought was dirty fuel filter, but nope - that's not the problem. After I towed it home, I borrowed an ODBC-II reader and got two codes off of it:

P0251: cam shaft position sensor malfunction injection pump A rotor

P0401: exhaust gas recirculation flow insufficient

I want to try and save some money by replacing the cam shaft position sensor myself, but I'm pretty far from being a mechanic. First challenge is to find where that part is even located. So I did some google searches but only come up with pictures and YouTube videos from different model years - and yup - my 2003 TDI looks different from, for example, the 2006 TDI in the video so that's doesn't help enough.

In my little bit of research I learn these TDI engines have names like "BEW" and "BRM". Mine, being a 2003 does not seem to be either of those names. Not sure what mine would be called? The car VIN (for what it's worth) is 3VWSP69M23M149599

I guess I want to know where this cam shaft sensor is located so I can replace it. But also, it seems everyone on this forum is so familiar with these engines maybe you guys can weigh in: based on the P0251 code am I daydreaming when I think my problem is limited to just the sensor? Or is this just the tip of a much larger iceberg? Any savvy advice I should be listening to?

The car is pretty old and has some other issues so it's not worth too much, so I'm not willing to put in a great effort to resurrect it.

 

[Mozambiquer]

The cam position sensor in your car is in the injector pump, I'd check all the wiring and also check the pump timing.

 

[KLXD]

OBD reader won't give you much meaningful info. Need VCDS.

I can't think of anything in the IP that would function as a cam position sensor. There's a crank position sensor and the #3 injector lift sensor that senses the injection event.

Try searching up that Code to see if anyone has translated it. I'll check the Book if I remember.

 

[STDOUBT]

I was driving on a medium speed road (80km/h or 50mph) and my 2003 Jetta TDI engine cut out. Very smoothly, no loud noises or strange vibrations. Just no RPMs.

Sounds like you don't have a real good history on the car's maintenance?
How old is the timing belt?
Your symptoms could easily be a slipped timing belt. If it was me 1st thing I would do is verify timing as I inspected the timing belt for lost teeth. 19mm socket on the crank, turn clockwise until you can see every tooth, then verify TDC.
Worst case, you need the head reworked. Really can't think of what else would do that.
Good Luck!

 

[JohnTF]

Off hand I think there is wrong & not enough info .
The limited amount of info 03 Jetta TDI , would indicate to me it is a ALH - I do not think this engine monitors the cam [ except with the timing belt ] , but no sensor .
Do not currently have a trusted VIN decoder to lockup , use to yrs. ago , not willing to play with a google search .
I like to look at the easiest / cheapest things 1st , but follow the info from testing , experience .
Possible fuel cutoff - electrical , check for voltage with key on .

 

[03_blue_jetta]

Ok after waiting out the winter I'm back looking into my car problem. I learned my engine is an "ALH" type. I now think the problem is something to do with diesel fuel delivery. I thought fuel filter - but nope, that's not the problem. Then maybe fuel pump (in the fuel tank), but ALH does NOT have a fuel pump in the tank - just a sending unit. So next thought is a fuel shutoff. Does anyone know where on an '03 Jetta TDI is the fuel shutoff reset?

Alternatively, it might be some problem with the high pressure fuel pump assembly. Maybe its timing got off somehow? Or maybe you guys have another idea?

Thanks!

 

[oilhammer]

How about start with a proper scan tool?

Not much needed to make an ALH run, and perhaps even less to keep it running once it is started.

If it loses RPM signal from the CKP sensor, it will not run... but those rarely ever fail. The ECU power relay ("relay 109") can cause the ECU to not power up, but that *usually* manifests itself as a no-start, not so much a stall. But a quick way to tell if the ECU is not powered up is the MIL (check engine light) will not come on when you turn the key on.

 

[JohnTF]

The fuel cut-off is in / on the fuel pump / distributor .
Making is easier on those that help , make it more likely to get answers !
Old post - should refresh what your dealing with , symptoms --- not requiring those following to back & reread , from 8 months ago

 

[03_blue_jetta]

Okay - thanks for the tips guys. Sorry - not trying to make it difficult to help me! Sort of a newbie on forums and maybe don't know way I'm supposed to post. But I appreciate that you're giving me some of your valuable time, so thanks.

So to summarize - autumn of last year I was driving along at 80 km/h and suddenly 0 RPMs. I pushed in the clutch and restarted car, 10 seconds later it died again and couldn't restart. I borrowed an ODB reader and got the codes mentioned above.

Oilhammer suggested "How about start with a proper scan tool?" but ya, best I could borrow was an ODB.

Anyway, since car won't run I can't get it to a proper garage for diagnosis. I had a mobile mechanic come over. He suspected a fuel delivery issue. So he cut out the middle-man: He disconnected the air intake from the air filter and sprayed ether (or whatever it's called - the engine starter spray). And then when I cranked it over the engine kicked and fired. Ran rough because it's a diesel and we're spraying ether into it but whatever - it did run and that's a big clue right there. IE my timing belt isn't broken, etc etc. Looks like a fuel delivery issue maybe. It was suggested that I locate the fuel shut off - hence renewing this old post. Thanks JohnTF for telling me where to look for the diesel fuel cut-off.

Car is over at my mom's place - in her garage so next time I'm over there I'll check for it.

And thanks also oilhammer for the tip about the engine light indicating ECU function when I turn the key. I'll also check for that next time I get to the car at my mom's place.

Funny thing though - last night I twisted my knee really badly. I'm on crutches now so no driving to my mom's to follow up on your posts. But I will as soon as I can.

Thanks again for your time and your help with this!

 

[dcjkrueger]

I have an 03 Jetta TDI 1.9 L ALH engine. I had the exact problem. Yes, it was the Crankshaft position sensor that would make my car stall and not restart and run until I let it sit for a while. It drove me crazy as it did not set a code at first. After a few months, it FINALLY set a code that indicated that the CPS ( Crankshaft Position Sensor ) was the culprit. I had the CPS replaced and have driven a good 60,000 miles since with no problems. I would go with the CPS first.

 

[03_blue_jetta]

Thanks dcjkrueger - that's also really good to know! Did you swap the Crankshaft Position Sensor (CPS) yourself? If so, how difficult was it to do that? Was it deep in the bowels of the engine and hours of work to get to it?

However, I do note a couple differences between your symptoms and mine: You wrote that your car would restart after you let it sit for a while. That's not happening for mine: it just won't restart (except briefly by spraying ether). Second, you wrote that your car didn't really throw an error code for a few months, and when it finally did your code was CPS. My car did have an error code right away after this episode. In fact mine threw two codes and neither code was CPS. I had

P0251: cam shaft position sensor malfunction injection pump A rotor

P0401: exhaust gas recirculation flow insufficient

But if I read between the lines from what oilhammer wrote above, maybe I can't 100% trust the info coming from an ODB reader?

Anyway, the CPS is a good idea. Is there a way to test my CPS to see if it's dead? Or does a guy just buy a new one and swap it in and see if that fixes my problem?

 

[JohnTF]

" Murphy Rules " is trying to lay claim to the car - and playing ugly - putting you on crutches
1st off , you do not have a cam sensor , but it should have a crank sensor - it would be located on top of the transmission .
Do a search for crank sensor - to get a look at one to see what your looking for .
If you have a good quality multimeter you should be able to see a pulsing voltage , not the proper tool , just a good indicator to start .
Have learn to think like a car , keep in mind 3 points a pyramid , #1 sensor = collect info for the #2 computer = computers make decisions according to it's program #3 actuators = open / close , turn on / turn off etc.
If it is the crank sensor , the computer does not see the signal so it does not turn on the fuel solenoid .
Generally computers control the ground on actuators - example gas fuel injectors , the positive is always on with ignition , the firing of the injector is turned on by the computer by making the ground connection .

 

[oilhammer]

The CKP is in the front of the block, right above the oil pan rail, near the oil cooler hoses. You get to it from underneath, but it plugs in up near the glow plug bridge in a bracket.

 

[Mozambiquer]

Ether sprayed in the intake does not verify timing is correct. It just shows that the timing between the cam and crank is close enough to fire on a highly volatile mist.
It won't tell you if your injection pump is in time, or even if your cam is.
My recommendation, pay the $199 and get vcds (or even get a kkl cable on eBay or Amazon and use the free vcds-lite) and start from there.
Verify timing using a pump lock (6mm bolt will be enough for that) setting the crank at TDC and checking to see if the cam slot is horizontal. Don't simply throw parts at it, as that is a very good way to waste a ton of time and money and not fix the problem.

 

[fatmobile]

How do you know the filter is good?

 

[dcjkrueger]

I had my CPS replaced by a mechanic. Would have done it myself, but getting advanced osteoarthritis in my hands. You can look it up on youtube. They have good videos on how to find it and how to replace it.

 

[AndyBees]

This is not a fuel filter issue........ period! Wasting time! If there are air bubbles in the clear hose from the filter over to the Injection Pump (IP) it is likely the fuel filter change has been botched.

Never use starting fluid on a TDI engine ... period.

As for a proper scan tool, nothing beats VCDS (Vag Com Diagnostic System)............... Go to Ross-Tech dot com and read!

OP, you need to heed the advice pertaining to verification that the Timing Belt doesn't have stripped teeth (which I doubt, but it should be marked off the list of things to do).

Check all the electrical connections at the IP ......... unplug, inspect and re-plug if all looks good (no corrosion or broken/frayed wires).

As others have said, the Crankshaft Position Sensor (CPS) is located on the block down low near the transmission (not on the transmission). It is held in place by a single bolt. Once you remove the bolt, likely the sensor need to be pried out. If I remember correctly, access from the bottom would be the approach.

My gut feeling is saying this is an issue inside the IP. (more reason to scan with VCDS)

 

[jettawreck]

Like Andy said, and others before, you first before all, need to prove that the TB has not failed and/or slipped. The shut down while casually driving and being able to somewhat restart (using ether/starting fluid is a big NO and says something about the mechanic that looked into it) has the classic "event" signs.

 

[jokila]

If you want to find someone in your are with VCDS use this link and see if anyone is nearby.

VAG-COM Diagnostic Service Locator

Searchable Map for VCDS Owners

www.maptive.com

To dogpile on the starting fluid diagnosis, that only tells you it can run, not that everything else is working correctly. It will mislead you into thinking it's a fuel starvation issue whereby people start suggesting changing out the fuel filter. Of course, that doesn't help since it wasn't a fuel starvation from the filter problem, but more than likely a fuel-at-the-correct-time issue, pointedly, the injection pump. The puimp does have a cutoff, so you have to rule that out or an out of time problem.

 

[03_blue_jetta]

First of all, thanks EVERYONE for so much help - that's great!

Taking in all the info I've received as well as some online searching, here are the possible causes for my non-start problem so far (more to come?):

1) timing belt out of position - looking into that
2) injector pump out of position - looking into that
3) crankshaft position sensor - looking into that (read below)
4) ECU - after checking it looks good
5) relay 109 (related to ECU) - removed relay and tested it, relay is fine
6) EGR -it definitely had some build-up inside but not super bad - cleaned it up
7) needle lift sensor - I see conflicting info whether this could cause my problem or not

In terms of the Crankshaft Position Sensor, it seems to have a bit of an odd-ball bolt to remove it. Anyone know what sort of socket or wrench is needed to take it off? Oh - wait - someone has surely already asked this - lemme check other threads.....

Yup - oilhammer gave a detailed post in 2020, and the upshot about this strange bolt head is: " VAG lists the part number as N-101-045-01 '12 point socket head screw' ..... A standard 9mm 12 point socket fits it." OK, will give that a try.

 

[jokila]

1) the belt cannot be of position, it's just a belt. Either the cam and/or injection pump can be in relation to the crankshaft. I would get the engine to TDC and inspect the pump sprocket alignment. It's easier than verification of the camshaft alignment. It's also the more likely culprit than the latter.

3) It's think it's a 9mm 12 point, or something close. I too had a problem once with it, it was intermittent. Mine went flaky and done around 425k miles. Easy to change out.

6) EGR is not going to cause a no start condition. However, the ASV, the auto shutoff valve that is attached to it certainly can.

7)I had a failure of lift sensor in the #3 injector once and it didn't affect starting or running of the motor, except it did cause the engine to have perma-limp mode. That's where the turbo will not spool up. I could still start and drive the car, but it it lacked power. I also had a troublecode for that in the engine module.

 

[03_blue_jetta]

1) the belt cannot be of position, it's just a belt.

Yes, sorry - I didn't make my statement clear enough. Instead of me saying timing belt out of position I meant what you're saying: that the cam timing is off (my item #2 above is the Injector Pump timing could be off so I wanted to list that as a separate item).

 

[03_blue_jetta]

Okay, got over to my broken down car in my mom's garage and checked several suggestions from you all. Looks like problem is the timing - just like so many of you said. At TDC the cam IS in correct position but the injection pump was off by three teeth. Loosened the belt, and repositioned injection pump so it's now set correctly and secured the belt. So the car should start now right?

Well, would't you know it - now my starter is fried. It must have been from when that mobile mechanic guy came over and he was cranking the starter for long periods of time (30+ seconds at a time?). Starter is now removed and the flywheel looks good (no missing teeth). So I put 12V across the starter and then faked out the key signal - yup the starter spins but the solenoid doesn't jump the shaft out to the position where it would engage the flywheel. So that's another problem to look at.

Oh - and I now have a flat tire too. Man - this car......

 

[Mozambiquer]

Okay, got over to my broken down car in my mom's garage and checked several suggestions from you all. Looks like problem is the timing - just like so many of you said. At TDC the cam IS in correct position but the injection pump was off by three teeth. Loosened the belt, and repositioned injection pump so it's now set correctly and secured the belt. So the car should start now right?

Well, would't you know it - now my starter is fried. It must have been from when that mobile mechanic guy came over and he was cranking the starter for long periods of time (30+ seconds at a time?). Starter is now removed and the flywheel looks good (no missing teeth). So I put 12V across the starter and then faked out the key signal - yup the starter spins but the solenoid doesn't jump the shaft out to the position where it would engage the flywheel. So that's another problem to look at.

Oh - and I now have a flat tire too. Man - this car......

Get a new Valeo starter or rebuild yours. They're not hard to rebuild, look at the link in my signature.

 

[jokila]

He might have a crappy one from a local parts store in there. Can those be rebuilt well?

 

[Mozambiquer]

He might have a crappy one from a local parts store in there. Can those be rebuilt well?

They can be rebuilt still, though I recommend replacing the drive with a Bosch one. if it's a parts store one.

 

[03_blue_jetta]

Hi guys - nope my starter is not from a parts store. It's the original factory part. But it is buggered. I'll look into rebuilding it. If that proves too difficult I will go to an auto-wrecker and for $95 I can get a used one. Thanks for the advice on this.

 

[Mozambiquer]

Hi guys - nope my starter is not from a parts store. It's the original factory part. But it is buggered. I'll look into rebuilding it. If that proves too difficult I will go to an auto-wrecker and for $95 I can get a used one. Thanks for the advice on this.

Wow! $95 for a used one? For $10 more I can get you a newly remanufactured Bosch one!

 

[03_blue_jetta]

Well - that's $95 Canadian dollars (about $74 USD). But it's not even in my city so I'd need to pay some shipping on that too. So ya - maybe looking into rebuilding mine could be a way to go.

 

[Mozambiquer]

Well - that's $95 Canadian dollars (about $74 USD). But it's not even in my city so I'd need to pay some shipping on that too. So ya - maybe looking into rebuilding mine could be a way to go.

Not as bad, but still a lot steeper than a lot of places down here