[ches170]

Had my car read and it says P1056 for VVT control motor bank 1 supoly voltage input too low.

The code pops up when im driving and would go away whenever i turn off my car and on again.
Also I just had my valve cover replaced 2 weeks ago and the code started happening a week after it.
Any idea what the problem is?

[ches170]

Went to an indy shop in va beach and they pulled a couple codes
29D0 combustion misfiring, cylinder 4
2A77 control unit, internal fault, valvetronic output stage
2A3f valvetronic, actuator motor power supply
2A38 valvetronic, monitoring, sluggish movement

They reprogrammed the DME for the valvetronic and everything is fine for now
They also found a ground wire a little worn out or something and they fixed it and should fix the combustion misfiring.

[Ebzzz]

Originally Posted by ches170

Went to an indy shop in va beach and they pulled a couple codes
29D0 combustion misfiring, cylinder 4
2A77 control unit, internal fault, valvetronic output stage
2A3f valvetronic, actuator motor power supply
2A38 valvetronic, monitoring, sluggish movement

They reprogrammed the DME for the valvetronic and everything is fine for now
They also found a ground wire a little worn out or something and they fixed it and should fix the combustion misfiring.

How did they fix the p1056? I have the same code

[frisbeeguy]

Think they fixed the ground wire on the top of the valve cover, not sure. As for fixing the code, the BMW TIS specifies to use ISTA to make the "Valvetronic" unit relearn the limit positions (Under service functions). Usually to avoid this issue, in ISTA, there's a "remove Valvetronic" that undoes the screw thing by 2mm so that its easy to pull out (you run that with your laptop attached to the car, then you undo the bolts to the Valvetronic unit), and then there's no need for calibration. Alternatively, if the code still persists after this, then you have to click "Calculate a test plan" in ISTA, and a bunch of diagnostic procedures will run (must have a charger attached to the car battery), and that will somewhat help determine if the Valvetronic motor is faulty or not.