Camshaft or Crankshaft???

Bri76

New Member
Hi all.
My 1.4 Diesel has had a bit of trouble firing up first time. I'm thinking camshaft position sensor or crankshaft?
The questions I have are:

Camshaft position sensor; is the one that sits just under the cambelt cover below the belt sprocket, right? - And is a fairly straight forward fix? < Is this the most likely one to cause the engine not to fire first time?

Can someone tell me where the crankshaft position sensor is located? (I did search, but no definite answer) - I believe that is a more involved kind of replacement?

Also, do either of these sensors have any bearing on the engine performance once the engine is running?

Thanks in advance for any advice
 

BiggDogg

A2OC Donor
Hello, why do you think it’s one of these sensors?
Have you done a scan with VCDS? This is the place to start.

Trouble with either of those sensors tends to cause either no start at all or issues whilst driving, rather than cold start problems. I think you replaced the glow plugs a couple of years back, how long has this been a problem?
You have the correct location for the cam sensor, the crank sensor is down by the oil filter flange housing towards the flywheel end and is a pain to change.

All the best,
Matt


Sent from my iPhone using Tapatalk
 

Bri76

New Member
Afternoon, Matt.

It went in for a basic service because I was getting the glow plug warning light flashing now and again - the garage said there were 2 fault codes showing, one was the brake position switch (which I fixed myself) and the other was either cam or crank position sensor - I can't remember which one he said. He did say the car will need turning over a few times before it starts... So I was wondering which of the two it will most likely be?

Thanks
 
Last edited:

TomA2TomAh2

A2OC Donor
This is timely. Our TDI has been turning over a few times before firing, recently, whereas previously it would fire on the second turn. A VCDS Free scan shows Camshaft Position Sensor (G40): No Signal p3007 Intermittent.

I inspected this at the weekend, and it is indeed the sensor that's on the UK driver's side of the engine, under the cambelt cover towards the top of the engine (near the camshaft, suprisingly!). The fiddliest bit I found was getting the plastic cover out, and back in again when finished.

I have a sensor on order. But if it helps when I removed the old one to check I was getting about - iirc, because I didn't make a note - 1840ohm resistance between pin 1 & 2, and pin 1 & 3. My gut says our symptoms are due to a interestingly kinked wire near the sensors multiplug connection, though.

The crankshaft sensor is buried down near the oil filter housing, like @BiggDogg says. I'd be running a scan first, before delving that deep in to the engine. A £5 eBay cable and VCDS Free will point you in the right direction.

Cheeky edit: I believe Crankshaft Sensor failure equals no start/run, Camshaft Sensor failure means falling back to the Crankshaft Sensor, and protracted cranking before firing.

Also, if you've not run a scan, do so. I went round the houses cleaning earth points, checking for diesel leaks, fully charging battery etc, before my VCDS cable arrived and then low-and-behold there was the P3007 error!
 
Last edited:

damadgeruk

A2OC Donor
Camshaft sensor failure caused slow starting on our departed Cobalt AMF TDI (particularly bad when hot starting), new sensor fixed this.
 

Bri76

New Member
Ok, thanks for replies. I'll tackle the cam sensor, seeing as that is the easiest of the two (and most likely the cause of the problem), if the problem remains, then I'll probably take it back to the garage.

*The cam belt cover is held by just two clips, right?

*Oh, and has anyone had any issues using "snide" parts? I'm thinking this:
 

Bri76

New Member
My Camshaft sensor arrived yesterday, and after fitting it, it fixed the problem. Fingers crossed you have a similar outcome @Bri76
Nice one - I'm glad you sorted it.
Still waiting for my part to arrive. Did you replace with a genuine part, or a cheaper version?
Any major issues changing it? You mentioned a plastic cover...
 

TomA2TomAh2

A2OC Donor
I used a Febi/Bilstein part as I happened to spot a cheap one on eBay.

No issues, just the aformentioned plastic cover that needs some wiggling and swears to get out, and back in to place.

Undo the three 10mm nuts holding the engine cover on. Undo two clips - one you can see, one behind that you can't - holding the cambelt cover and remove (this may be where you spend most of your time). Look down the front of the engine at the three glow plug wires, and the wire running left-to-right behind those is the one you need. Follow that towards the engine side of the cambelt cover, and poke around a bit and you'll find a rubber grommet, remove that. Continue following that wire to find the sensor. It's held on with one 10mm bolt tucked up nearest you, close to the belt itself. Remove that. Unplug the multiplug (push the clip down as you push it together, then pull apart... it makes sense when you do it). Unthread the sensor through the handy grommet hole. Done.

Then do all that again, in reverse!
 

Bri76

New Member
I used a Febi/Bilstein part as I happened to spot a cheap one on eBay.

No issues, just the aformentioned plastic cover that needs some wiggling and swears to get out, and back in to place.

Undo the three 10mm nuts holding the engine cover on. Undo two clips - one you can see, one behind that you can't - holding the cambelt cover and remove (this may be where you spend most of your time). Look down the front of the engine at the three glow plug wires, and the wire running left-to-right behind those is the one you need. Follow that towards the engine side of the cambelt cover, and poke around a bit and you'll find a rubber grommet, remove that. Continue following that wire to find the sensor. It's held on with one 10mm bolt tucked up nearest you, close to the belt itself. Remove that. Unplug the multiplug (push the clip down as you push it together, then pull apart... it makes sense when you do it). Unthread the sensor through the handy grommet hole. Done.

Then do all that again, in reverse!
Thanks for that. Hopefully I can do it over the weekend (if it turns up!)
 

Bri76

New Member
Friends, let this be a lesson to you all...
The sensor arrived today, I spent an hour fitting it - it doesn't bloody work! Buy cheap, buy twice etc... Very disappointing.
I've now ordered a genuine Audi part... :(
 

Un4tural

Member
Bit late but thought it might help - crank sensor was a pig to do as had to remove oil cooler (undo it and swing out of the way), was quite messy and had to go do/undo bolts by finger feel for sensor but not terrible, certainly had my hands in worse.

Got a genuine sensor off a mate and it works fine, looking at one that was in car it was a no brand no logo affair, it has a bit of metal with plastic around it is seems, and plastic started to come off the metal with oil in gaps...

I changed it right away (about a few months now) but it caught me out at a parking lot at shops, it would crank but not start with coil light on, after resting for a little it fired back up and was fine.

was very fiddly.

For reference it was https://www.ebay.co.uk/itm/Cranksha...del:A2&hash=item23a15af2f8:g:8DcAAOSwx5lapwy5

Shared with Polos and other VAG cars so relatively cheap part - if it cranks and doesn't start with coil light blinking it sounds exactly same as my issue. Can't find the code i had sadly, but it was crank sensor related.

Oil level sensor failed about a week after and that was a breeze to do relatively.
 

Bri76

New Member
Bit late but thought it might help - crank sensor was a pig to do as had to remove oil cooler (undo it and swing out of the way), was quite messy and had to go do/undo bolts by finger feel for sensor but not terrible, certainly had my hands in worse.

Got a genuine sensor off a mate and it works fine, looking at one that was in car it was a no brand no logo affair, it has a bit of metal with plastic around it is seems, and plastic started to come off the metal with oil in gaps...

I changed it right away (about a few months now) but it caught me out at a parking lot at shops, it would crank but not start with coil light on, after resting for a little it fired back up and was fine.

was very fiddly.

For reference it was https://www.ebay.co.uk/itm/Crankshaft-Sensor-Crank-Angle-Fits-Audi-A2-2000-2005-1-4-TDI-7YO/153030947576?fits=Car+Make:Audi|Model:A2&hash=item23a15af2f8:g:8DcAAOSwx5lapwy5

Shared with Polos and other VAG cars so relatively cheap part - if it cranks and doesn't start with coil light blinking it sounds exactly same as my issue. Can't find the code i had sadly, but it was crank sensor related.

Oil level sensor failed about a week after and that was a breeze to do relatively.
Ah, I'm fairly sure mine is the crank sensor at fault. @PlasticMac mentioned the rev counter moving when turning over, and mine does move, also replacing it with the snide, cheap part caused it not to start at all... Genuine part now on order.

Fingers crossed the crank sensor doesn't go anytime soon!
 

PlasticMac

Member
Ah, I'm fairly sure mine is the crank sensor at fault. @PlasticMac mentioned the rev counter moving when turning over, and mine does move, also replacing it with the snide, cheap part caused it not to start at all... Genuine part now on order.

Fingers crossed the crank sensor doesn't go anytime soon!
🤞
Mac.
 
Top