[chris145]

About 2 weeks the engine management message came up on the Sat Nav (reduced power, please contact dealer etc.) on my 07 335i (pre LCI). After stopping and restarting the message went away. I drove it a little after that and the message didn’t come back. I booked it in at the dealers shortly after. They had it for the day and said that their where a few error messages to do with the wastegate actuator, and they would need it for 3 days to diagnose further. I was told I had to wait for another week or so for a loan car to be available but I could drive my car in the meantime. I must have driven at least 100 miles in that week and the error never came up. It went back in on Monday and today they called me to say they couldn’t see what the problem was. The service advisor said they would take it for a longer test drive tomorrow to see if anything comes up but failing that there was nothing more they can do, and I could then pick the car up. Thankfully the car has most of the 1 year warranty remaining, but I am worried there is an underlying problem that they have not picked up.
Has anyone else experienced this sort of error that goes away on its own?

[Jon D]

I'm surprised that the error message wasn't latched into the ECU and that the dealer couldn't detect it. I don't have any experience of car ECU diagnostics, but they're computer based control systems and, I would think, broadly similar to those in aircraft, which I do have experience of.
Fault codes are stored in the memory and are therefore detectable by diagnostic software; however, there are different levels of access within the programme and they all need to be looked at.
I'd be surprised if automotive ECU systems were vastly different in this respect; I wonder how deeply your dealer probed.
Caution signals usually mean that something is amiss; it's obviously nothing major at this point, but it could indicate an incipient problem. These things rarely go away of their own accord; at least you have the peace of mind with your warranty.

[E92westy]

IIRC codes can be cleared after a certain number of starts, if they don't re-occur.
No expert myself though, either....

[m1bjr]

There are codes and shadow codes.
Not all errors produce an idelible log in the 335i ECU.
Some O2 sensor errors cause a warning that is not logged but will appear on the dash until and engine restart.
I do find this car 'noisy' and have had a couple of odd random codes that never re-appear.

However...
Wastegates ARE a known issue on the 335i - there are two of course.
It's not unknown for (normally rear) actuator arms to require tightening or adjustment.
It's a pig of a job and expensive to sort though, so my guess is they are being lazy.
Many owners report wastegate rattle - slightly reving the engine causes a clatter, like a rattly exhaust, as the revs drop back to idle.
That's a turbo out job.

Steve

[Jon D]

Originally Posted by m1bjr

Its a pig of a job and expensive to sort though, so my guess is they are being lazy.

If that was the case, it would explain their reluctance to carry out the work under warranty.

[MEGA]

Originally Posted by Jon D

If that was the case, it would explain their reluctance to carry out the work under warranty.

Unlikely. Franchised BMW garage X doesn't care whether it is you paying for the work, or BMW UK. It doesn't affect their own margins...

[NFS]

Originally Posted by chris145

About 2 weeks the engine management message came up on the Sat Nav (reduced power, please contact dealer etc.) on my 07 335i (pre LCI). After stopping and restarting the message went away. I drove it a little after that and the message didn’t come back. I booked it in at the dealers shortly after. They had it for the day and said that their where a few error messages to do with the wastegate actuator, and they would need it for 3 days to diagnose further. I was told I had to wait for another week or so for a loan car to be available but I could drive my car in the meantime. I must have driven at least 100 miles in that week and the error never came up. It went back in on Monday and today they called me to say they couldn’t see what the problem was. The service advisor said they would take it for a longer test drive tomorrow to see if anything comes up but failing that there was nothing more they can do, and I could then pick the car up. Thankfully the car has most of the 1 year warranty remaining, but I am worried there is an underlying problem that they have not picked up.
Has anyone else experienced this sort of error that goes away on its own?

Probably the high pressure fuel pump.

[chris145]

Thanks for all the reply’s. Picked the car up yesterday. Service advisor said they reset everything and took the car for a long test drive and couldn’t get the error to re-appear. I tried listening for any rattles when I rev the engine but couldn’t hear anything? Will it rattle when I rev the engine while stationary or while driving? If there is really an underlying issue I’m sure (hoping) it will come up within the next 11 months before the warranty expires, and I will seriously consider extending the warranty after that.

[zltm089]

Take it for a very long test drive....my warning message occured after 1hr 25mins of driving...

[zltm089]

whats the mileage on the car?

[chris145]

Originally Posted by zltm089

whats the mileage on the car?

Milage is about 38k. Will try take it for a longer drive after Christmas.