I've got a 2015 R60 S in limp mode and throwing a 2C3F code. It has the newer version high pressure fuel pump which I replaced to no avail. Took it to a shop and they said they "thought" it was a bad ECM and suggested replacing it "to start" at the tune of about $3K. I declined and pulled the ECM and CAS module and sent them off for diagnosis. The test company said the ECM tested fine and sent a video of a car they had installed my ECM in running fine. But it was also showing the 2C3F code on their reader. They said it was because their test car had the older version high pressure fuel pump. I had them send everything back and I reinstalled the ECM and CAS module and it is doing the same thing. I've also swapped out the high pressure fuel pump relay. Guess it is possible that the new high pressure fuel pump I put in is defective. Or it could be that the ECM is fried even though the test company said it isn't. Anyone have experience with this? Thanks

 

Replaced the ECM with a cloned replacement. No luck. Unplugged the wire from the HPFP and started the car. Ran the same as with it plugged in. Would think that the HPFP is bad or there is a short in the wire somewhere. HPFP has been replaced already. Tried doing a live reading on the HPFP to see if I could see a problem with the fuel pressure. Not real sure how to interpret what my code reader said, but the nominal and actual readings were about the same.

This all started with a failed thermostat. Replaced that along with the crossover tube to the water pump. Put everything back together and it was acting up with the 2C3F code and limp mode. Checked to see if maybe a wire was connected wrong, but all of them seem to be able to connect to one place only. From internet searches it seems that others have run into this type of thing after messing with the thermostat. At a loss. Thinking about ripping the wiring harness apart to see if I can physically see a broken wire somewhere. Basically given up on the car as a driver, so figure I can't damage it much more than it already is.

 

The 2C3F code is related to the upstream O2 sensor…
https://bmwfault.codes

 

Thanks. Code reader message is "quality control valve, activation: line disconnection" HPFP or wiring harness issue. Without macgyvering a way to test the fuel pressure between the HPFP and the fuel rail, I don't know any other way to test the HPFP. Debating whether I want to throw more money at it and try another HPFP. Attempted repair costs are getting close to exceeding the value of the car.

 

Rereading your posts I noticed again that this started with a thermostat replacement.... Maybe the fuel pump connector got buggered during that procedure? Try unplugging the fuel pump, cleaning the connector, and plugging it back in?

 

Following. Removed ECU to replace the thermostat and then also found the gaiter had a crack next to the turbo (which may have been causing an intermittent stumble). Replaced the thermostat and rehooked up the ECU. Wrapped the gaiter crack and the car ran like a champ...unfortunately the car has also lost its mind (Footwell Module) that I now have to reprogram. In the meantime the smell of raw case is coming from the tail pipe and it appears the intermittent stumble has returned. I have not got a code read from the car yet.

 

I think there were some extended warranty and recalls on those footwell modules... You should check into that if you haven't?

 

Follow up. Unwrapped the wiring harness from the HPFP to the ECU and traced the white wire all the way to the ECU connector. No visible breaks in the wire. Orange wire is hot and runs to a point in the harness where it meets several other hot wires. No visible breaks in the wire. Could not check continuity of the white wire because I can't tell for sure which pin it runs to in the connector. There are a mass of them in a tight spot. But visually it looks like the wires are OK. And the ECU itself is good. So it must be in the connector or the new HPFP is bad. It is a Bosch unit from an online parts house that only cost about $200 vs the $1000+ for a genuine mini/BMW part. Debating tossing another $200 at it to see. Not going to spring for the $1000 one.

 

What was the final outcome?

 

also curious

 

Would like to know if it was fixed and how


.

 

I had the same problem, so thank you German engineers, wire for thermostat and wore for HFPP are same plug and as per diagram same colors depending on the pump model , they are neat each other and easy to misplug in wrong connector, this was the problem in my case , easy to make that mistake if you changing thermostat and water pipe.