Rex drivetrain error when coming to a halt

[ajmfulcher]

I'm trying to resolve a frustrating issue with my i3 Rex. After 30-odd minutes of running, it'll generally (although not always) throw a drivetrain error. This always seems to happen when coming to a standstill, as the Rex is turning itself off. The drivetrain error will clear after 10 - 15 mins of the car being switched off (or if cleared via OBD), but will then happen again in a shorter period of time.

I'm seeing two fault codes when this happens:
105001 - Crankshaft sensor, signal: missing
114001 - Engine oil pressure switch: switch is closed

And then the drivetrain error itself:
CD8C2A - Deactivation of the combustion engine due to an internal fault

The crankshaft sensor error seems to throw 5km or so before the oil pressure and deactivation ones. Sometimes shows a CEL.

I've had the crankshaft sensor replaced, but no real difference. Oil level good. The unit itself seems to run fine, except for this issue.

Any suggestions? ECU? Oil pressure sensor? Low oil pressure? I'm thinking it might be temperature related, as it only seems to happen when warmed up.

 

[AndyWright]

Have you ever found what's going on? I've got the same errors in the same situation and even appeared at the junction as well. It seems like it turns off REX  because you've stopped the car on a traffic light, THEN it notices that there is no oil pressure, panics and leaves you with just electric power.

 

[ajmfulcher]

Sorry, just saw this!

No, no further along. Have you made progress?

 

[helpmycar]

I'm having the exact same issue with mine - originally the range extender would work intermittently, sometimes I would get 50miles and then have to leave it for 15 minutes or so, and then maybe get another 5-10 miles out of it. After a while it would be more like 5-10miles and then for a while it wouldn't work at all.

Firstly I swapped out the fuel pump relay, and all of a sudden it was working again, but then after 20 miles of use I was getting the same drivetrain errors (only electric range possible, etc.). So then I tried replacing the 12v battery, as the car had fully died one night in a car park after having interior LEDs on while vehicle was in park - so seemed logical that a dying battery was the cause of the range extender failure.

After replacing 12v, again it seemed to work perfectly, got maybe 20 miles out of it however and same drivetrain errors again. However it does seem to work a lot more regularly than before, whereas before it would sometimes not work at all/max for 1-2 miles, whereas no most time I will get 20 or so miles out of it.

Also got the same fault codes as you as well as 117000:
117000: Fuel tank pressure/temperature sensor circuit: Malfunction or open circuit
105002: Crankshaft sensor, signal sync error
114001: Engine oil pressure switch: switch is closed
D04C1E: sub-bus failed/tank pressure sensor does not respond.

Also the interior lights seem to be blinking as though the 12v is dying, however as I have just replaced it I wonder if this is just an unrelated fault such as the LEDs themselves going, however I'd be curious to know if anyone has experienced similar electrical faults alongside the range extender issues.

Have you or anyone with similar issues had any look getting this fixed. I tried taking to a BMW garage initially, but there approach was to run a "fuel sample test" for £300 and add some additive to clear any carbon deposits, and if that failed to fix the issue (no surprise it didn't fix anything), was a fully REX replacement which would cost £3-£5k :lol:

 

[alohart]

Also the interior lights seem to be blinking as though the 12v is dying, however as I have just replaced it I wonder if this is just an unrelated fault such as the LEDs themselves going, however I'd be curious to know if anyone has experienced similar electrical faults alongside the range extender issues.

Check that the screw-on battery terminal posts and the battery cable clamps are tight. The terminal post screws especially tend to loosen.

 

[JimBmwi3s]

Maybe it’s the exterior gas door is not closing properly???? Is there a message for that?

 

[hadaR1150R]

Hello ajmfulcher and helpmycar and Andy,
did you ever find out what your issue was? If you got it fixed, what was the fix?

I have 2017 Rex and I'm seeing same errors in Bimmerlink:
105001: Crankshaft sensor, signal: missing
114001: Engine oil pressure switch: switch is closed, pressure too low
CD8C2A: Deactivation of the combustion engine due to an internal error

And the Rex motor will only run from about 10 to 20 minutes at a time. Seems like an overheating issue, because if I let the car sit 2 or 3 hours, the Rex will run again for another few minutes. But it sounds nearly identical to what ajmfulcher described last August.

Check Engine light has been on some times, but then after I ran the engine in emissions inspection mode, it went out.

I have checked oil and all coolants.

See my posts here
https://www.mybmwi3.com/threads/question-on-engine-coolant-maintenance-schedule-125k-miles.18162/

One possible culprit in my case is gas that got too old (and started to stink). I'm slowly working that old gas out, but can't figure out how that would cause the Rex shutdowns - unless the old gas for some reason causes the Rex to get especially hot.

Did anyone find out what kind of "internal error" triggered CD8C2A error?

Appreciate your response,
Jeremy, NY

 

[hadaR1150R]

On one of the other threads I found recommendation:
Proactively replace REX fuel pump relay (blue), multiple cases of relay contacts failing

Did any of you try that?

 

[dafireman12]

Anyone find a solution, have the same problem. Fuel pump Relay did not fix the problem for me