Vacuum Leak / exhaust gasket problem

[Mudguts]

Hello all,

I have exhaust fumes leaking into the cabin through the air vents of my 2002 Z3 2.2i Facelift. My Foxwell diagnostic tool gives me the following errors:

Code	Description	Meaning
CA	Fuel trim bank 1 control limit	ECU has reached the limit of fuel correction on Bank 1
CB	Fuel trim bank 2 control limit	Same on Bank 2
E3	Fuel trim bank 1 permissible range exceeded	Long-term adaptation has gone too far
E4	Fuel trim bank 2 permissible range exceeded

(decoded with the help of Chat GPT)

Has anyone had this problem before and is it easy to fix? The garage that I trust are telling me that it could be the pre or post catalytic converters, which could be expensive to replace (I really am repeating what they have said verbatim, as I'm not mechanically savvy at all).

I also have the dreaded DSC error light that illuminates and disengages the DSC after about half an hour of driving. I have managed to source a replacement ABS/DSC module, but replacing it looks a little complicated. Has anyone done this before?

Any help/advice would be much appreciated as I only have 55K miles on the clock and the car is in really good condition.

Cheers

Ludo

 

[Stevo7682]

Hi the 2.2 is quite bad for the studs disintegrating between ghe primary and secondary cats and the exhaust leaks this can be repaired.

Your abs / dsc needs to be checked for faults before you start putting pumps in ( as if the dsc pump same as the asc pump then its coded and traction control wont work but it looks like it is )
Zeds are bad for abs sensors ( dsc different from asc sensor ) there can also have master cylinder pressure sensor switch failure and another major one to check is the yaw sensor which is under the carpets under the passenger seat
If you lift the seat to full height stick your hand under the seat from front you will find a joint in the carpet where the front meets the rear carpets open it with your fingers stick your hand down between them afar as you can get see if the foam is wet .
If it is that aint good for the yaw sensor as it is not waterproof.
Like i said get the abs codes read first before starting changing bits.

The picture are a 3.0 but 2.2 essentially same that flange bad for leaks an exhaust fabricator would fix that in no time if thats what issue is new bolts and flanges
Rest of the exhaust are generally reasonable.
Stephen.

 

[Mudguts]

Hello Stephen, thanks so much for the reply.

Do you think that the exhaust leak from those points would find their way into the cabin, as this is what's happening?

The yaw sensor could be a good shout, as I had a hardtop that leaked over the passenger side. But wouldn't that mean that the error light would be permanently lit? Mine only cuts in after about 30 mins of driving.

Cheers

Ludo

 

[Andyboy]

Is it an exhaust leak or oil dripping from the cam cover onto the exhaust manifolds?

Replacing the ABS pump is tricky, and you have to be so careful referring the brake pipe unions to avoid cross threading into the alloy pump housing. Screw them in by finger pressure only carefully to 'start' them.

It might be a rain damaged Yaw sensor. It's under the carpet, drivers side. But as above, you need to interrogate the system first.

It's worth buying a smoke testing machine from eBay (about £35). I have one and it's invaluable to finding air leaks.

 

[Mudguts]

I got these fault codes from my Foxwell diagnostic: