Limp mode and 2ABC on full throttle

Kurt_

New Member
Jan 5, 2023
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I've been having an ongoing issue with my 2008 E61 535xi. It drives fine 99% of the time, except in certain situations where i floor it with a heavy load (ie from a slow speed or uphill). It will then throw a code for 2ABC boost sensor short circuit to positive and go into limp mode. Apart from the lack of boost, the engine still runs well in limp mode. This does not occur any other time, or when I floor it under a lighter load (ie from 100 km/h to 150 km/h).

Some vehicle history: I bought it with an unknown history in 2018 or so. The turbos don't rattle and feel strong - they must have been replaced prior to my purchase. Since then I've put a lot of work into the car. Focusing on the engine, off the top of my head, it's got new index 12 injectors, boost sensors (both), a new cable from the boost sensor to the ECU. VRSF 7.5" intercooler. Reasonably recent plugs and coils. silicone vacuum lines. Just refreshed the VANOS solenoids too.

Stage 1+ MHD, ACN91.

I let off the throttle at 11.24 seconds. It goes into limp mode when I let off the throttle, but it always pulls well up until that point. From the error details, limp mode can be pinpointed to the time where rpm is 5024 and the throttle valve is 1.87°TPS. It seems to be exactly when I let off the throttle.

I feel like I've ruled out everything so I'm open to any advice, opinions, or things to try. Or maybe you know a better forum to ask. I'm out of ideas.
 
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Kurt_

New Member
Jan 5, 2023
2
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0
Apologies, I had tried but as it is my first post it got stuck in approval with a link.
datazap.me/u/kurt/2abc-full-throttle-and-heavy-load?log=0%data=3-20

I did realize I have been setting the tune's option for wastegate rattle to full "less lag". It looks like they do something funky when I let off the throttle. Maybe they need to be opened more. I was thinking of reflashing with a middle setting.

Let me know what you want me to log, it's an incredibly repeatable issue.