New check engine light...Help!

[gpep77]

Hey guys! First time posting here. Have owned my m5 since March of 2022 and am unfortunately having some problems with it and want to get some insight as I don't think my BMW dealer knows what the F they are doing and I am tired of throwing money at it.

Car is a 2014 m5 competition with no modifications. Approximately 57,000 miles on it.

On a cold start a few weeks ago the vehicle turned on with a check engine light. Drove the car home and parked it in the garage until I could get it into BMW for diagnosis. Drove fine on the way home and on the way to BMW for diagnosis. They pulled the codes and told me the crankcase ventilation hoses were leaking and throwing a fault code (not sure what code). Spent almost $1,000 for the hoses to get replaced to find out the car had new codes after that they could not clear. They told me the car had aftermarket filters that were oiled and damaged the MAF's and it would be $1,300 to replace. Claimed it was coincidental and had nothing to do with the initial check engine light. I am not an expert mechanic, but have done my fair share of engine work at home so I laughed at the quote and took my vehicle home.

Sure enough the filters were not OEM. They were BMC filters. MAF's looked pretty clean, but might have had some residue on them. Long story short, I ordered brand new OEM filters and Bosch OEM MAF's and have replaced all of the parts to unfortunately find the vehicle still has a CEL and is throwing a code.

Codes before replacing MAF's and filters:
102002
102902
118111

Cleared the codes and put a few miles on the vehicle before the CEL came back on.

Code after clearing codes and driving for a few miles:
102002

Car seems to be driving fine. Possibly idle is a little more inconsistent than prior but its probably me just paying too much attention to it. Seems to hover around 700-900 RPM's once warm. No stalling, hesitation, or significant loss of power; however, I haven't driven it hard since the CEL came on.

Any ideas?! Thanks in advance guys. I really appreciate it!

[M5Rick]

Fuel cap not on with the click, fuel filler ventilation hose could be kinked or blocked and when were the spark plugs last changed OR it could be bad gas.

[DL7]

Check your injectors. They can cause some of the codes and you have already replaced the MAF sensors. They are a known issue with our car and are covered under an extended warranty.

[gpep77]

Just for my knowledge. What makes you feel it has something to do with the fuel system? Fuel cap on tight. Haven’t changed gas stations since ownership so unlikely to be bad gas but certainly possible.

[DL7]

I had similar check engine light and codes for bad gas, airmass, rich. After lengthy diagnosis a MAF sensor was replaced and the check engine light went away. Not even a month later and less than 500 miles, I had loss of engine power on highway and limp mode due to 2 leaking injectors. Leaking injectors can cause rich and air mass codes as the ecu tries to compensate.

The dealer tech suspected leaky injectors from the start but said they have to follow bmw testing protocol. When the check engine light went away after the MAF sensor replacement they still suspected there were leaky injectors but told me their hands were tied on injector replacement under warranty due to no codes.

I have a ‘14 completely stock and this happened recently with 38k-39k miles on my car. Not saying this is definitely your problem but sounds similar to what I experienced. HPFPs are also a known issue and also have an extended warranty.

[Yellowbee]

Yep. Keep it simple. Get a new oem gas cap. Yes it will click yet not seal. Start there.

[gpep77]

Thanks for all of your input guys. I’ve reached out to my service advisor and will be getting the car in asap. Will update when I have more info.

[gpep77]

Update: took car to bmw and they are telling me the brand new oem replacement MAF sensors I ordered are faulty as they did not come from bmw. They are claiming the Bosch oem replacements that don’t say bmw on them are not the same quality. Can someone chime in? Thanks

[ECB]

I've always used the Bosch oem replacements and never had an issue.

[M5Rick]

Dealer doesn't want to know if critical parts are replaced and not stamped BMW.

[m5rosco]

Where were the Bosch MAF's from? There's lots of counterfeit parts out there nowadays that really are below par. Could it be they aren't real Bosch?