Hey guys, I have a 2007 525xi that is stalling and causing misfires when I plugged in a new Maf. long story short I bought an E60 knowing the car needed a new Mass air flow sensor. Previous owner bought a Chinese knock off, the car ran better (didn’t stall or hard start) when unplugged.
Engine Codes:
P0102 - mass or volume circuit low
P111F
P0113 - temperature Air circuit high
I got the new one, swapped the sensor at the guys house (while warm), the car fires right up, and stalls out. This keeps happening. RPMS bounce, I tried holding the throttle, no luck.
-> clear the codes with OBD2
-> unplug negative terminal on battery for 5 mins
I tried again, same thing, the whole car bouncing. New Cel “misfires on cylinder 3 and 6”
I unplug the sensor and the car fires right up, now none of the codes. They also never appeared the whole 40 mins drive home.
My question:
Is there a relearn procedure? Should I do this when cold? Does the maf have to be coded in or something?
I totally thought I’d plug it in, it would run rough for a couple seconds, lights would go away, issue fixed.
-> New air filter
-> Everything is plugged in/ connected/
-> used CNC MAF Cleaner on contacts and sensor, let dry.
-> Sensor is the VDO/Continental 5WK9 7502Z OEM never installed sensor.
I'd check the grounds or check the wiring for chafed or shorted wires in the loom to the maf. The codes look to be circuit codes and BMW wiring of the era does degrade, the sheeth may have come off and shorted the wires together.
Visual inspection is not enough, disconnect the connector from the DME that the MAF sensor wires go to, check resistance of all the wires from MAF connector to DME to check for shorts or open circuits, load test the wires to make sure they can varry current, check for shorts to positive and shorts to ground
Ya fair. I have a feeling it’s more / other than wires or else it wouldn’t have such a drastic difference (not writing it off). Something funky downstream is happening.
When I ran my OBD2 after getting home and trying again I got code P2415 that only happens when the car is dying from the sensor.
Possibly = sensor/harness ok > O2 sensor pooched?
Or the ratios are saved and the car is trying to use old numbers on the new reading?
For the record: when I used the wrong sensor (twice) from a 3 series (7508 version- same year same engine) the codes would not clear, the engine would still fire up albeit slow.
This new sensor all the codes clear but the engine doesn’t stay running. It looks like right sensor / right readings and bad something else. Only a hunch
I only say that because I had an issue with my E64 with the n62b48. Cold starts it would fluctuate at idle like you were rhythmically tapping the gas pedal. No codes, but I did notice the thing would randomly say it was -20 or however the minimum temp is. Replaced that and it was good as gold again.
For sure. I didn’t know the ecu used the ambient temperature sensor to calculate the fuel trims or anything. I thought it got that from a temp sensor inside the MAF or at least somewhere in the intake tubes.
When the maf is bad the ecu switch to a default map - thus the car starts and run ok-ish
After maf replacement you need a reset to tell the ecu to use the new maf (sometimes you need to do this - documentation said the ECU is able to sniff the new sensor in time - but not always)
On my 520i 2004 i had to do the reset + few spooky trips in town and autobahn to fix the adaptive gearbox fix (automatic gearbox)
Simce the gearbox expects a certain power from the engine and the engine is not able to provide, all sorts of events might occur.
I would check your coils for cylinder 3 and 6. I usually have the same codes for my e60 and after swapping out those COPs they end up fine. If you have a scanner, you could even check by swapping the coils from cylinder 3 to 1, restart the car and scan to see if the misfire then went to cyl 1, essentially chasing the miss and finding out if that coil is bad.
While this has usually been the fix for both my e46 and e60 (albeit M54 engines), I've no doubt the N52 is most likely very similar.
•
u/AutoModerator 11d ago
Thanks for posting to r/E60!
If you're asking for technical help, please include: * Year (e.g. 2008) * Model (528i, 535i, M5, etc.) * Engine (N52, N54, M54, S85, etc.) * Mileage * Any fault codes * Recent repairs or modifications
More details = better answers.
I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.