Throttle Actuator Codes?

[slider86]

Hi all,

After driving for about 20-30 miles and after making a pitstop on the way home, I started the car up and seemed fine until a few seconds later, when the car got very rough. Another half min or so into the start-up, I got the "Engine Malfunction, Reduced Output and Driving Possible" and "Increased Emissions" messages along with 4.5k limp mode. Drove home conservatively, 10-15 miles mostly on local traffic, after making sure there wasn't any noise out of the ordinary coming from the engine bay. Car was less and less rough during the drive home, and eventually felt pretty normal (albeit with less power from limp mode). Got home, powered it down for a few minutes, and started up again with my code reader. Engine Malfunction light went away, and the start up was noticeably less rough than the pitstop startup, but Increased Emissions persisted. I pulled the below codes for Engine Electronics:

1. 274B: LAMBDA PROBE PUMP CURRENT BALANCE ERROR BEFORE KAT BANK 2
2. 2728: LAMBDA PROBE THRUST DIAGNOSIS IN FRONT OF KAT BANK 1
3. 2B35: MISFIRING WITH SHUTDOWN CYL. 1
4. 2B36: MISFIRING WITH SHUTDOWN CYL. 2
5. 2B37: MISFIRING WITH SHUTDOWN CYL. 3
6. 2B38: MISFIRING WITH SHUTDOWN CYL. 4
7. 2B41: MISFIRING WITH SHUTDOWN SEVERAL CYLINDERS
8. 2B57: ENGINE EMERGENCY PROGRAM ACTIVATED
9. 2796: ENGINE EMERGENCY PROGRAM ACTIVATED
10. 2B42: COMBUSTION MISFIRING EXHAUST GAS DEGASSING CYL. 1
11. 2B43: COMBUSTION MISFIRING EXHAUST GAS DEGASSING CYL. 2
12. 2B44: COMBUSTION MISFIRING EXHAUST GAS DEGASSING CYL. 3
13. 2B45: COMBUSTION MISFIRING EXHAUST GAS DEGASSING CYL. 4
14. 2B4E: COMBUSTION MISFIRING EXHAUST GAS SEVERAL CYLINDERS

Some background: car has 61k on the odometer, and motor was recently replaced with a BMW remanufactured unit, along with a new fuel breather valve and new Bosch ignition coils. It's been flawless for the past 900 miles since the motor was replaced (still in break-in period), and up until today, each startup has been like the car just came off the production line. I don't think it's the ICV because I'm only getting codes on one bank, and I don't think it would be coils since they would typically appear one at a time. Spark plugs came new with the motor from BMW, and coupled with the same logic as the coils (i.e. cyl 1-4 at the same time), I don't think they would be the culprit. I'm left with the following:

1. Failing actuators (most likely given mileage, the fact that all but one error seems to be related to bank 1, and 4.5k limp mode, though I don't see the code in the app reader)
2. Exhaust manifold leak (all gaskets were replaced with the motor replacement)
3. Injectors (same logic plugs/coils where I would only expect to see one or two if there's an issue, perhaps issue with fuel rail?)

Any pointers will be much appreciated. Thanks!

[fs34]

I always recommend checking the ground connections in these threads, I’ve had similar errors. For bank 1, check the connection on the bolt farthest back closest to the inside. Bank 1 ignition has a ground there. Make sure the nut is secure.

This may not be it but is an easy thing to check. If you have the intake off, check the nuts that hold down the engine harness.

Good luck, hope you solve it quickly.

[Jkan]

Originally Posted by slider86

Hi all,

After driving for about 20-30 miles and after making a pitstop on the way home, I started the car up and seemed fine until a few seconds later, when the car got very rough. Another half min or so into the start-up, I got the "Engine Malfunction, Reduced Output and Driving Possible" and "Increased Emissions" messages along with 4.5k limp mode. Drove home conservatively, 10-15 miles mostly on local traffic, after making sure there wasn't any noise out of the ordinary coming from the engine bay. Car was less and less rough during the drive home, and eventually felt pretty normal (albeit with less power from limp mode). Got home, powered it down for a few minutes, and started up again with my code reader. Engine Malfunction light went away, and the start up was noticeably less rough than the pitstop startup, but Increased Emissions persisted. I pulled the below codes for Engine Electronics:

1. 274B: LAMBDA PROBE PUMP CURRENT BALANCE ERROR BEFORE KAT BANK 2
2. 2728: LAMBDA PROBE THRUST DIAGNOSIS IN FRONT OF KAT BANK 1
3. 2B35: MISFIRING WITH SHUTDOWN CYL. 1
4. 2B36: MISFIRING WITH SHUTDOWN CYL. 2
5. 2B37: MISFIRING WITH SHUTDOWN CYL. 3
6. 2B38: MISFIRING WITH SHUTDOWN CYL. 4
7. 2B41: MISFIRING WITH SHUTDOWN SEVERAL CYLINDERS
8. 2B57: ENGINE EMERGENCY PROGRAM ACTIVATED
9. 2796: ENGINE EMERGENCY PROGRAM ACTIVATED
10. 2B42: COMBUSTION MISFIRING EXHAUST GAS DEGASSING CYL. 1
11. 2B43: COMBUSTION MISFIRING EXHAUST GAS DEGASSING CYL. 2
12. 2B44: COMBUSTION MISFIRING EXHAUST GAS DEGASSING CYL. 3
13. 2B45: COMBUSTION MISFIRING EXHAUST GAS DEGASSING CYL. 4
14. 2B4E: COMBUSTION MISFIRING EXHAUST GAS SEVERAL CYLINDERS

Some background: car has 61k on the odometer, and motor was recently replaced with a BMW remanufactured unit, along with a new fuel breather valve and new Bosch ignition coils. It's been flawless for the past 900 miles since the motor was replaced (still in break-in period), and up until today, each startup has been like the car just came off the production line. I don't think it's the ICV because I'm only getting codes on one bank, and I don't think it would be coils since they would typically appear one at a time. Spark plugs came new with the motor from BMW, and coupled with the same logic as the coils (i.e. cyl 1-4 at the same time), I don't think they would be the culprit. I'm left with the following:

1. Failing actuators (most likely given mileage, the fact that all but one error seems to be related to bank 1, and 4.5k limp mode, though I don't see the code in the app reader)
2. Exhaust manifold leak (all gaskets were replaced with the motor replacement)
3. Injectors (same logic plugs/coils where I would only expect to see one or two if there's an issue, perhaps issue with fuel rail?)

Any pointers will be much appreciated. Thanks!

I’m in a similar situation and have been doing a lot of research. This is a pretty old thread so I hope it was fixed but I’ll leave some info here for future readers.

Your first two code is related to the pre cat oxygen sensors. The pre cat sensors are heavily relied on by the DME/ECU to calculate Air Fuel ratio amongst other things.

I strongly recommend inspecting your o2 sensors (also known as Lambda) prior to taking off plenum, regardless if you get a o2 code, or if the codes are saying ICV, MAF or anything else. It’s a quick check before just throwing money at it. Another thing you can do is utilize live data and functional test.

Live data should read your O2 sensors (bank 1 Sensor 1, Bank 2 sensor 1 are the pre cat/upstreams) oscillating between 0.1v to 0.9v. If it’s stuck at either end, your DME/ECU will start giving extra fuel trim (pulling or giving more fuel), which could lead to either a rich or lean running engine, which can lead to idling issues and throw ICV code. Not being able to read oxygen properly could also lead to other fault codes like secondary air pump fault code since it can’t detect the correct o2 level (very common where people replaced SAP, valve, tubes, and still get SAP error).

For functional test, with a more advanced scanner tool, which any reputable shop should have, you can keep the engine off (ignition On) and run certain actuators. For example, I was able to activate my ICV, both throttle actuator, and pump through the scan tool. Now, it doesn’t rule out those items completely, but be able to hear them activate and move is certain a good sign.

Hope this helps!