E46 330ci Fault.

[Cledus Snow]

Had a strange problem with my car this evening. Cruise controi at 40mph through the Huntingdon roadworks on the A14. when i suddenly lost cruise control and got a brake, traction control and tyre pressure warning lights come on. The cruise control switched back on and worked fine and the lights are probably a wheel speed sensor or ABS ring. However i also have a missfire. No engine lights but it's as flat as Holland and has a rough idle. Tried switching it off and on again and it took alot of cranking to restart.

Any ideas?

[Cledus Snow]

Took it in to have it looked at this morning, started, ran and drove fine with no lights. Got 5-6 miles, it coughed and lights and misfire returned.
Code reading shows crank position sensor, MAF and timing faults. As well as ABS fault.
The code reader also showed the battery at 12.07v.

So dead/dying battery? But it still cranked over well, sounding strong and not at all slow.

[Cledus Snow]

Borrowed a shiny new 100ah Varta battery from work. Will sling that on tomorrow and see what’s what...

[Cledus Snow]

Chucked the new battery on. 12.8v with ignition off, 14.7v running. Went for a quick round the block test run and 5 miles in all the lights and misfire return.
Plugged back in and all the same codes are back.

[Cledus Snow]

Started fine this morning, no lights and ran fine. Swapped the battery and still had no lights/issues. Took it for a run, did about the same distance as yesterday and all the lights/runnings problems reappeared. Plugged in and got the same current faults as with the old battery.

[Cledus Snow]

d_a_n1979 said:

Cledus Snow said:

Started fine this morning, no lights and ran fine. Swapped the battery and still had no lights/issues. Took it for a run, did about the same distance as yesterday and all the lights/runnings problems reappeared. Plugged in and got the same current faults as with the old battery.

Do as I've suggested above; read codes/reset codes/unhook battery/leave unplugged for 30 mins or so/reconnect/go for drive and see if codes come back.

If they do, you have those specific issues

Shall give it a whirl tomorrow.

[Cledus Snow]

Ok, codes cleared last night. Battery disconnected and left over night. New battery fitted. And it’ll still only go 5 miles before it all fails again.
Crank sensor changed and wouldn’t start at all. Second new sensor delivered and fitted and it now starts but with the same faults although the MAF fault has gone away.

This is what is on the code reader





Answers on a postcard to...

[Cledus Snow]

Right then. I have the car back, i’ve Spoken to a local specialist who has suggested either vanos failure, a stretched cam chain or both.

Which is fair enough, it could be. However the interweb seems to think M54 chains could lift a super tanker’s anchor and the vanos is fairly sturdy too. And it still doesn’t Explain the wheel speed themed Xmas lights on my dash.
I guess he must be pretty good as he can’t look at for a week...

[Cledus Snow]

Obison said:

I would bet a battered sausage its the crank and or cam sensors failing,

Right then, where would you like your bartered sausage posted to?

Plugged in and checked over by a specialist this morning. He’s 99% sure it’s a duff crank sensor. So a new genuine BMW part is on the way and being fitted tomorrow.

[Cledus Snow]

• Update.

Without wanting to tempt fate as i’ve only done 20ish miles. All seems good. All lights out, power back and normal starting. £100+vat for a genuine crank position sensor seems to have sorted it.