Engine Malfunction: Code: 2AAF

[ensoniq]

2006 335xi automatic.


when accelerating rapidly error comes up; "Engine Malfunction: Reduced Engine Power..." and SES light come up.


scanned, shows: code 2AAF "DME: Fuel Pump, plausibility".


I am reading and searching and reading finding different answers:
to replace LPFP, HPFP, LPFP sensor, charge pipe leak e tc..




Any values I can check for or live data parameters when when driving to figure what the problem is ?


(I have Autel maxisys and launch pro3 x431 diagnostic scanners.)

[ensoniq]

Now also new code got added:
30FF: turbocharger, boost pressure too low.

[Joel Torres]

I have the same problem with the same code how you fixed the problem 2AAF.

[154e90]

2AAF is a meaningless code. BMW documentation says to ignore it unless you are having other issues or symptoms. Do not replace parts for 2AAF alone with no symptoms.

30FF means you have low boost pressure. This means that either you aren't making boost or that you are making boost, but it is leaking out. You can check desired boost pressure vs actual boost pressure if the PIDS exist, but that code is already telling you that the DME was monitoring those values and they don't match. Other than looking at the boost solenoid control signal or map sensor with an oscilloscope, there isn't much electrical diagnosis to do. It is pretty much all physical inspection now. You can look at fuel pressure vs desired fuel pressure for both the high and low sides, but I think this is a boost problem and not a fuel problem.

First, unplug the brake booster vacuum line and see if you hear a whoosh sound as air enters the system. A good vacuum system will do this hours after the car has been turned off. Let us know your results.

Here is a revised description I wrote a while ago of how the system works:

Vacuum:
The engine generates vacuum by spinning the vacuum pump. Vacuum canisters were added to hold a vacuum reserve under high vacuum use. The vacuum supplied to the canisters comes from the brake booster line. This vacuum is supplied to the vacuum canisters, the boost solenoids, and then the wastegate actuators, in that order. If there is a cracked line, there may not be enough vacuum to let the components work as intended, as air is entering the system and turning the vacuum into regular atmospheric pressure. If you unplug the line and hear nothing, then there is a leak that already let all the air in beforehand.

The wastegates:
The turbos have a normally open wastegate flap that is only closed when vacuum is applied to the wastegate actuator. This flap lets exhaust gasses bypass the turbo so the car creates no boost. When vacuum is applied to the wastegate actuator, the flap closes and exhaust gasses are forced through the exhaust turbine, which spins the compressor wheel, which makes boost. The rattle sound people often hear is this flap rattling against the bypass port it seals off. This is fixed either by adjusting the wastegate actuator rod, or fixing an issue with vacuum supplied to the wastegate actuator.

Boost solenoids:
The boost solenoids have an input vacuum line and an output vacuum line. The input line connects to the vacuum canisters. The output line connects to the wastegate actuators. These are controlled by the computer using a square wave signal. This turns the solenoids off and on really quickly. This connects the wastegates to the vacuum lines and disconnects them very quickly. The duty cycle or "% on time" of the signal from the ecu to the boost solenoids controls vacuum pressure to the wastegates, which controls how closed the flap is, which directly controls boost.

If your car has a massive vacuum leak, the wastegate actuators will never move and you will never have boost. This is why you are checking if the brake booster line holds vacuum.

There can also be a boost leak anywhere between the turbo outlets and the intake valves. Usual spots are a broken charge pipe and the intercooler ends.

Here is a link to that thread:
https://www.bimmerforums.com/forum/s...7#post30537407

[sleeper bird]

on my 08 335 1 the low boost code and limp mode was due to cam tray ledge rings.