B Class B170 2007 Powertrain errors suddenly

Page may contain affiliate links. Please see terms for details.

AdamE

New Member
Joined
Jul 2, 2021
Messages
15
Location
London UK
Car
B170
Hi All,

I hope you can help me. I got a panicked call form my friend who has a lovely B170 2007 model. It's been flawless so far (he got it secondhand) with only teh throttle body needing to be cleaned to clear a rough running over a year ago now (was full of that brown sludge that aparently they get). It was a nice easy job and the car has been smooth and great since.

Yesterday I got a call to say it wouldn't 'go into gear' - and after a bit of a chat I realised that it was going into gear, but the car was conking out as soon as it was put in, plus it sounded a bit lumpy.

I popped over and plugged my cheapo OBDII in, and ran Torque, to see what was happening. It gave the following attached errors. It does start, although it takes longer than normal, plus it is definitely missing (I Presume on Cylinder 2). I think that's why it dies when put into gear as it just can't cope with the torque of the gearbox suddenly. If I quickly whizz it down to N it's fine (although still missing slightly).

At one point a huge red message came up on the info screen when it conked out, saying about low oil pressure, but I am pretty sure that is just because it conked out while trying to go into gear... there was a very short 'pSHHHHt' when it conked that time (although not on others) - which I presume is a relief valve doing what it should do.

Luckily it did it on my friends street, and they managed to push it back into it's parking space.

Apparently the story of the intial conk out goes:

Started a bit hesitantly in morning
Drove down road but forgot keys so went back to house (while friend sat in car running)
Put in gear
Died

The day before it drove fine.

Fingers crossed someone has a clue as I am normally an MG man (don't shoot me down LOL) so used to simpler cars than the B Class.

Thanks in advance.
 

Attachments

  • Merc erros.png
    Merc erros.png
    894.2 KB · Views: 7
The codes suggest an issue with Camshaft positioning, probably a camshaft position sensor.

As you used a generic OBD tool it would be best to have the faults scanned by Star which will be much more specific.

The B2AAA code suggests an incompatibllity between the OBD Scanner and the car
 
Thanks for that - OK better try and find a garage with scanner n ear my mates place in East London... think it's gonna be an expensive fix! Do you think the camshaft sensor would cause the Injector Circuit fault though? That was red (i.e. an actual fault rather than impending) before I cleared the codes and re-ran the engine - so I was thinking maybe the judder caused by that was giving the position sensor issue?
 
Thanks for that - OK better try and find a garage with scanner n ear my mates place in East London... think it's gonna be an expensive fix! Do you think the camshaft sensor would cause the Injector Circuit fault though? That was red (i.e. an actual fault rather than impending) before I cleared the codes and re-ran the engine - so I was thinking maybe the judder caused by that was giving the position sensor issue?
I would wait until you can get a better diagnosis with Star.

Camshaft position sensors have been known to fail or give abberent signals which can cause ECU to lose position of the camshafts and cause issues with injector timing.
 
To add :

Fault codes, especially OBD type can be misleading or, often are an indicator as to what the actual fault is.

Each manufacturer will have their own specific list and that is why it is often recommended to use a more sophisticated scanner like Autel, Icarsoft or the MB Ster6/Xentry system for specific fault and component level diagnosis.

This MB specialist is highly recommended but might not be convenient :

 
Last edited:

Users who are viewing this thread

Back
Top Bottom