F30 320d Drivetrain Error

[SuperAd]

Hi Guys,
I'm having a bit of drama getting a resolution to an error code on my 2016 320d. I took it to one local garage, they said it was a flexray issue, a second garage refered me to a third as they don't deal with flexray, and the third said it wasn't flexray at all!

After the diagnostics were run, its coming back with:
28DE00 - Exhaust back pressure before turbo
28EC00 - Exhaust gas pressure sensor upstream of Exhaust turbocharger
290900 - Air mass system, measured air mass too high
290B00 - Air mass system, measured Air mass too low
2AB600 - Exhaust backpressure sensor before turbine too high
36F500 - Air intake system: plausibility

I'm not expecting free mechanics advice, but just to check my logic. It seems like a straight forward Exhaust pressure sensor swap would sort this, as the equal/ opposite nature of the faults leads me to believe the car doesn't know what's going on.

Anyone of you lovely people had any similar experiences with this?

Cheers

[rottenegg]

You can try new differential pressure and exhaust pressure sensors and hope it also sorts the air mass faults at the same time. Does the engine feel like the DPF is plugged?

[SuperAd]

It's driving normally to be honest. It states high performance not available, but I can't tell

[d_a_n1979]

Might sound simple and you may have checked this, but have you checked voltages and battery health?

These cars do like to throw issues/codes when the battery isn't in peak health

[rottenegg]

SuperAd said:

It's driving normally to be honest. It states high performance not available, but I can't tell

OK. You don't normally feel bunged up DPFs until higher up in the rpm band. If the iDrive is saying performance is limited, I would get the DPF looked into.

If you have Bimmerlink and a dongle, you can force a regen and see if it helps. With Bimmerlink, you can also see what the differential pressure through the DPF is. It should be way down in the 0.1 - 0.3 bar region.

Has any work been done on the car recently that could have disturbed the sensors and or wiring?

[SuperAd]

EGR replacement through the recall about 8 weeks ago. If that's what's gone they'll replace it. It's going into a local garage next week. I was intending to replace a few easy sensors myself to see if that sorted it, but its MOT is due soon, and I've not got the time to have a few stabs in the dark. It'll be interesting to see what needs doing.

[PapaPete]

Hello. Sounds like the same problem I'm having after EGR replacement. Did you find out what the fix was?

[rottenegg]

Exactly the same fault codes?

Perhaps take it back to whoever did the work and ask them to look at it?

Seems strange that's happened immediately after the recall. I would try resetting all of the DME and emissions adaptations if you don't get anywhere with the garage and see if the codes come back. You'll need ISTA for that though.

FlexRay fault codes are often a red herring, certainly with ISTA. It's usually either a time out or the engine needs to be running when doing a full scan. You would know if Flexray (the optical bus) really was down!

[PapaPete]

Dealer said they'd do a diagnostic session and fix if its something they've done but if its coincidence and related to something else it will cost me £200 so was trying to avoid that