M47 - restricted power fault

[timejV]

Hi everyone!

I'm new to the forum, so please move the thread if I didn't put it in correct subforum, I just thought it will fit the best since it is about diagnosing....

Here is the problem... On my dad's '04 freelander td4 with a bmw m47 engine (that's why i'm posting to a BMW forum) there is this thing when whenever you exceed 60 mph the car goes in reserve program or whatever it's called and the check engine light with an exclamation mark inside comes on. The car has very little power, almost like the turbo doesn't do anything anymore. When you turn the car off and on again, the problem goes away, but as soon as you exceed 60mph for a couple of seconds, it comes back on again.

The car came back from the mechanic today, he cleaned the MAF, since it wasn't giving correct values to computer, but the problem is still here. I went back with the light on, and two error codes came up.. The first one just said security or safety, I can't remember what it was, and the second just said advise before proceeding, again, it was something like that, I didn't remember what exactly it said. He cleared all the faults, checked engine parameters when idling and when under load, but he didn't notice anything out of order. He then reset the engine computer (I think that is what he did, maybe he just reset the stored values?), but the problem is still persistant.

Did anyone have the same issues or has any advice for what to check, since the car will go back to the mechanic on wednesday..

Thank you

[328 Power 04]

Definitely sounds like limp mode. You need to read engine codes to know exactly why. Otherwise you're guessing.

[timejV]

Definitely sounds like limp mode. You need to read engine codes to know exactly why. Otherwise you're guessing.

Thank you for your reply!
Yes, limp mode was exactly what I meant, just couldn't remember what's it called in english. Well, the car has been on diagnostics and it showed 2 very strange faults, first one just said secutity and the other that you (mechanic) should advise before proceeding.. He than cleared all the fault codes and reset computer (not exactly sure what, but he did reset something) and that was it... I was on the highway today, same thing happened, but no lights showed up and the engine did have a bit more power... at least it felt so, or maybe it has to do with MAF being cleaned?

[328 Power 04]

Cleaning a MAF pretty much never fixes anything, it's usually just a small useless attempt at fixing something.
Will definitely need the actual error code and if available, the diagnostic scanner's interpretation of it.

Limp mode most often happens because of either overboosting (dirty or stuck turbo vane/actuator mechanism) or underboosting (boost leak, or stuck turbo actuator mechanism). But there are other reasons as well, so even when there are not lights coming up, there will be fault codes.

[timejV]

Cleaning a MAF pretty much never fixes anything, it's usually just a small useless attempt at fixing something.
Will definitely need the actual error code and if available, the diagnostic scanner's interpretation of it.

Limp mode most often happens because of either overboosting (dirty or stuck turbo vane/actuator mechanism) or underboosting (boost leak, or stuck turbo actuator mechanism). But there are other reasons as well, so even when there are not lights coming up, there will be fault codes.

I agree, but he cleaned just to see if it helped for a while, so we know if the problem is there or not..

I am currently making appointment with someone who is a really good mechanic and knows how to use a diagnostic tool... and I mean REALLY USE it, so I will make sure to post a picture of all the readings and faults if he can't figure out what is the problem... but for what i tested today, the light doesn't come on, and the performance is slightly better, but i florred it in 4th gear to arround 4000rpm (i don't do this, but it was just to see what happens) and after staying at that rpm you could feel the power go away and the going in to limp mode after a few seconds...