[dbworld4k]

Hey guys, loving my Cobb tune so far except one issue that seems to surface infrequently. It happens during WOT and only about 10% of the time if not less.

• 09 N54 335i
• 6spd manual
• 85k miles
• I believe original plugs/coils
• 94 octane

There are no other drivetrain mods to the car; stock DPs, stock FMIC.

It feels severely debilitating and somewhat dangerous (ie. when overtaking). The car ran flawlessly before the tune.

The symptoms are:

• sudden cut-off of power and fuel (feels similar to fuel starvation when at a track during hard cornering while low on gas, for those that can relate), and the car abruptly yanks as if someone slammed the brakes hard.
• it goes into Limp Mode (reduced power).

Restarting the car puts it back to normal and it can be driven WOT for a while before re-triggering.

These are the codes I pulled:

• P0238 TurboCharger Boost Sensor Circuit High Voltage
• P3100 misfire code
• 2ABC TMap fault?
• 2AAF a quick search says to ignore this one as it is not significant

Any help would be appreciated!

[135Pats]

If it was truly cutting out fuel i'd expect to see a rail pressure code of some type...Those are some weird codes you are throwing. Hmmmm.

So no cobb = no codes?

If you are on 80K mile old plugs and coils, they should be replaced now. Like right now.

[dbworld4k]

Yeah I intend to change the plugs and do walnut blasting ASAP.

Searching for P0238 doesn't yield anything significant either. Seems like a somewhat unique situation, lol.

No tune = no cutoff/problems even in high humidity hot days like last month.

[e92_enthusiast_1]

Your plugs and coils needed bad IMO. Just for starters.

[Ingeniator]

Originally Posted by e92_enthusiast_1

Your plugs and coils needed bad IMO. Just for starters.

Check tour TMAP sensor and harness. it could be a dirty plug or cracked wire casing.

[dbworld4k]

Just thought I'd post an update now that the problem has been solved!

- Changed plugs, did the walnut blasting, and cleaned the throttle body. The car drives MUCH, MUCH better and smoother! The throttle feels much more responsive.
- Upon reinstall of the intake manifold and components, one of the charge pipe's bungs broke. Replaced with an almost new OEM pipe due to urgency. Wish I was able to throw a BOV in there

I am very curious if the frail/about-to-break OEM charge pipe's bung had a small leak; that it may have triggered the TMAP fault of P0238 as the sensor is right there.

Any thoughts?

[Jeff@TopGearSolutions]

Originally Posted by dbworld4k

Just thought I'd post an update now that the problem has been solved!

- Changed plugs, did the walnut blasting, and cleaned the throttle body. The car drives MUCH, MUCH better and smoother! The throttle feels much more responsive.
- Upon reinstall of the intake manifold and components, one of the charge pipe's bungs broke. Replaced with an almost new OEM pipe due to urgency. Wish I was able to throw a BOV in there

I am very curious if the frail/about-to-break OEM charge pipe's bung had a small leak; that it may have triggered the TMAP fault of P0238 as the sensor is right there.

Any thoughts?

Anything possible depending on the condition.

You could also CAREFULLY clean the TMAP with Mass air flow sensor cleaner. You should consider a CP upgrade sooner then later so you are not stranded on the side of the road when it will ultimately fail.

[135Pats]

Not sure but i'd really replace it with an aftermarket piece as suggested. The stock unit will fail, it's just a matter of when.