[Fl_Rza_99]

I turned my car on Monday morning and got an error as I pulled out of my parking spot. Drivetrain malfunction, power reduced, take to service center... Later in the day, after work, I hooked up my obd scanner and found code 131401; vanos, exhaust, cold start. Wasn't really sure what this meant so I took my car to one of the independent shops. Got a call this afternoon and they say my timing chain/tensioner are off and will have to be replaced.... for a cost of... $5660 😨. I'm new to bmws and have had the car for a little over 4 years. Bought it with 43,000 and now I'm at 82,000. I was careful and researched what could go wrong with the n55 before I bought this car. I knew some of the common flaws, and have dealt with a few, but I didn't see this issue mentioned. Any ideas what could cause such a big problem?

[Fl_Rza_99]

For anyone who may run into the same issue, I did not have them do the recommended repair. The advisor told me more frequent oil changes can keep the problem from progressing. Took the car home and have not had a check engine light on since. The codes still show up when I scan. When turning the car on from a cold start I don't notice anything suspicious, warm starts are crisp. I will be getting a second opinion from another mechanic.

[F22Cam]

How often were you doing oil changes ?

[NxTH]

I had this exact symptom, but only when it was humid or raining and doing a cold start. Restarting the car got rid of the error. My code was on the intake side. Changed solenoids, camshaft sensor for intake and checked if there was sludge going up to the solenoids, checked fuel filter cap that the cage was still attached and o-rings were still there, but those were all dead-ends. Also tried different oils, 5W30, 5W40. Finally found out that the problem was caused by my ground strap that was partly eaten by a rat and rest was just badly corroded. IF your problem seems to come on when it's humid, I would start with checking various wiring harnesses, straps and connections for corrosion. It's baffling why the code points to VANOS, and it *can* be an issue that is not VANOS related at all. Perhaps the moisture trips a sensor and the VANOS just doesn't do what it's supposed to.

[Fl_Rza_99]

Originally Posted by F22Cam

How often were you doing oil changes ?

I was doing oil changes once yearly or every 10,000 miles. I'll be doing them every 6 months going forward.

[LA1Z24]

Originally Posted by Fl_Rza_99

I was doing oil changes once yearly or every 10,000 miles. I'll be doing them every 6 months going forward.

10k miles is 5k miles too many

OEM service info is only 10k miles so when youre in the dealership they can tell you

"THIS CAR IS SO CHEAP TO OWN, OIL CHANGES EVERY 10k MILES!!!"

This is a trap. These cars are made for THE FIRST LEASEE (RENTER) ONLY!

[Fl_Rza_99]

Originally Posted by NxTH

I had this exact symptom, but only when it was humid or raining and doing a cold start. Restarting the car got rid of the error. My code was on the intake side. Changed solenoids, camshaft sensor for intake and checked if there was sludge going up to the solenoids, checked fuel filter cap that the cage was still attached and o-rings were still there, but those were all dead-ends. Also tried different oils, 5W30, 5W40. Finally found out that the problem was caused by my ground strap that was partly eaten by a rat and rest was just badly corroded. IF your problem seems to come on when it's humid, I would start with checking various wiring harnesses, straps and connections for corrosion. It's baffling why the code points to VANOS, and it *can* be an issue that is not VANOS related at all. Perhaps the moisture trips a sensor and the VANOS just doesn't do what it's supposed to.

I'm in Florida and on that day there was a cold front, temps dropped a good bit. This has only happened once. I'll be doing an oil change tomorrow morning and will check on the timing chain, will see if its loose or not. Thanks for your input, i'll check the harnesses while i'm at it.