Reduced power - not throttle actuators

[Justin Case]

Hey guys,

I recently got my e92 m3 back on the road after some years and I went to drive it this morning. Made it 300ft and got a reduced power warning.

I had this before and have had the throttle actuators replaced and upgraded.

No other errors codes like before when the actuators were dodgy.

The car has also had all 8 ignition coils replaced as 3 were faulty.

Any ideas as to what’s going on? Sorry no access to codes atm.


Cheers!

[spammysammich]

If you didn't use genuine coils, it's likely misfiring but you won't know without pulling codes. Nobody makes aftermarket coils that work worth a damn anymore.

[Justin Case]

Genuine coils were used as saw issues with aftermarket ones. No sounds of misfiring.

The engine reduced power lets me keep it in manual and seems to have normal power just reduced revs.

[nick3753]

What do you mean by “back on the road after some years”?

[Ajolives]

Was it just reduced power? Did you get any other system malfunctions - ABS, traction control, etc?

[Justin Case]

It was not used for 4 years due to various reasons.

No other errors codes only restricted power and revs lower to 4k. Engine still seems to have full power up until 4k revs

[RocketyMan]

Originally Posted by spammysammich

If you didn't use genuine coils, it's likely misfiring but you won't know without pulling codes. Nobody makes aftermarket coils that work worth a damn anymore.

OP...Like was mentioned before, you need to pull codes. Otherwise this is a useless guessing game.

[Justin Case]

Originally Posted by RocketyMan

OP...Like was mentioned before, you need to pull codes. Otherwise this is a useless guessing game.

Any code readers you’d recommend?

[amrazM]

need to perform fuel pressure test with ista.

[RocketyMan]

Originally Posted by Justin Case

Any code readers you’d recommend?

Oh heck yes. I would totally recommend ISTA D and INPA.

With ISTA D, you have: pertinent fault codes per your chassis (some other code readers can only give crappy generic codes), fault code literature, wire diagrams, pictures showing component location, service routines, service panels, list goes on.

Just get the ICOM adapter and do some google searches for getting ISTA D setup. There are quite a few other forums that help guide this.

[Justin Case]

Originally Posted by RocketyMan

Oh heck yes. I would totally recommend ISTA D and INPA.

With ISTA D, you have: pertinent fault codes per your chassis (some other code readers can only give crappy generic codes), fault code literature, wire diagrams, pictures showing component location, service routines, service panels, list goes on.

Just get the ICOM adapter and do some google searches for getting ISTA D setup. There are quite a few other forums that help guide this.

Oh very nice! Thanks for the recommendation. More I know more I can let the garage know in advance as I’m many miles away from them!

Time to do some research!

[ruff1017]

Also check the battery level
It can throw some codes if the battery level is low.

[CamasM3e93]

Battery level, as above. Also battery terminal tightness- that got me at my purchase with a loose terminal.

I also have had the low power management come up related to the brake boost vacuum sensor failing and later the vacuum pump itself.

[fuddman]

One thing to keep in mind, FWIW, the reduced power condition (limp mode) always generates a DSC (Dynamic Stability Control) fault light as well as a brake warning light.

That's because the DSC system, to function correctly, requires unrestricted throttle control as well as brake control. Otherwise, it wouldn't be able to "control" your skidding.

With the DSC & brake light on, what BMW is telling you is "don't get into an uncontrolled skid because the DSC system we put into your car no workee when in the limp mode."

[Scrippy]

I smell electrical problems. A harness problem or low voltage. The aforementioned should throw a code. I mean 4+ years makes the battery suspect to me.

[fuddman]

I'm chasing a limp mode problem, too.

If the car has been sitting for a long time, there may be chance mice got into the engine area and ate some wiring.

I stored mine for some weeks and found a small rats nest in what is called the "valley." That is the valley that's formed between the throttle bodies. It was virtually impossible to see, being nestled just below, and hidden by, the thermostat housing and its assorted paraphernalia. I stumbled on it by accident.

The BMW "enhanced" codes I'm getting are CD93, CDBF, and the 2B57.


When the ECU throws code 2B57, it commands the car to go into limp mode. Based on what ECU criteria, no one knows.

The other two BMW codes are described using the terms "BUS" and "CAN." These terms are are related to communications, in my case, broken communications. "BUS" and "CAN" are part of the system by which electronic information is transmitted throughout the car between the various sensors and the ECU. That exchange of information is conducted through wires, aka, rat food.

Did the rats eat my wires? That's what I'm looking at now?

Notice the BMW codes do not point at a specific part and say "change this part." Rather, the these codes, at best, insinuate by providing clues. You need to put on a detectives hat to solve it. Or, alternatively, as someone else put it, "Load up your parts cannon." Oh, and your wallet, too.

[CamasM3e93]

Originally Posted by fuddman

I'm chasing a limp mode problem, too.

If the car has been sitting for a long time, there may be chance mice got into the engine area and ate some wiring.

I stored mine for some weeks and found a small rats nest in what is called the "valley." That is the valley that's formed between the throttle bodies. It was virtually impossible to see, being nestled just below, and hidden by, the thermostat housing and its assorted paraphernalia. I stumbled on it by accident.

The BMW "enhanced" codes I'm getting are CD93, CDBF, and the 2B57.


When the ECU throws code 2B57, it commands the car to go into limp mode. Based on what ECU criteria, no one knows.

The other two BMW codes are described using the terms "BUS" and "CAN." These terms are are related to communications, in my case, broken communications. "BUS" and "CAN" are part of the system by which electronic information is transmitted throughout the car between the various sensors and the ECU. That exchange of information is conducted through wires, aka, rat food.

Did the rats eat my wires? That's what I'm looking at now?

Notice the BMW codes do not point at a specific part and say "change this part." Rather, the these codes, at best, insinuate by providing clues. You need to put on a detectives hat to solve it. Or, alternatively, as someone else put it, "Load up your parts cannon." Oh, and your wallet, too.

Your rat nest was right on top of your throttle actuators and that’s a common throttle actuator code. The throttle actuators themselves should physically be protected from damage but maybe the rat did chew into wiring for one of them. You might have to remove the components in the valley to inspect more closely. Lots of light, patience, and perhaps magnification during the inspection