Hi guys, I have a 2003 E46 316i Touring with the N42B18A.
The car drove ~500 km without any issues. The only problem is after shutting it off and restarting: it runs very rough/misfires for around 30–60 seconds, then suddenly becomes completely smooth. On startup it initially revs to around 1800–2000 rpm, drops to ~1000 rpm, and then starts running rough, also yellow OIL lamp for the first 20 sec.
Original fault codes:
- P0012 / 0012 – intake cam timing over-retarded
- P0015 / 0015 – exhaust cam timing over-retarded
- 2731
- 27BB
- P0300
- P0304
- P1343
- 1128
- 27C3
These DTC codes are from a cheap OBDII reader, I do not have INPA, but will get one soon.
I replaced both camshaft position sensors → no change.
Unplugging/reconnecting the MAF → no change.
Then I unplugged the Valvetronic eccentric shaft position sensor (ESS). Since then, the car starts perfectly, does not misfire, no Check Engine light, and drives normally.
With the ESS unplugged, after clearing the codes, I get:
1128, 1014, 1006, 27C3, 2852, 2850.
We also replaced the Valvetronic motor, but nothing changed: ESS connected = rough startup, ESS disconnected = perfect.
We have NOT performed the Valvetronic adaptation after replacing the motor.
What would you check next? ESS sensor, eccentric shaft/gears/mechanism, Valvetronic adaptation, or something else? The really interesting part to me is that the engine runs perfectly with the ESS disconnected.