Fault code 5E
 

my SES turn on and I got the fault code 5e. I replaced the MAF Sensor and the EGR Valve hoping that it was one of those but to no avail the code keeps coming back after a somewhat long drive (10miles). Air filter is new and secondary air pump is working so Im kinda stuck. What should I check next? Any advise is greatly appreciated.

Replaced the MAF with an OEM or genuine Seimens MAF or some cheap crap you brought on fleabay or Amazon?

I bought a genuine Siemens MAF at OEMBIMMERPARTS.COM. EGR valve was bought from my local bmw dealership

I think you have an evap problem. Something is not sealing the gas tank (could be a loose fuel cap) or a leaky hose. How long have this been going on?

A couple of weeks. My car now has about 90k miles on it (not sure if relevant to my issue).

This weekend, I will look look around the engine bay again and check for vacuum leaks. If I cant find any leaks...have no choice but to send to my local dealership and have them diagnose the issue.

An evap leak is not a vacuum leak. The evap system controls the gas fumes in the gas tank. There is a pump that pressurize the system and a sensor that tells the computer that the system is not leaking.

I'm guessing your purge valve may be clogged or taken a dump (just a guess)

do you normally fill up at the gas station with the car running?

My car is always off when i fill up. Im not a mechanic so I have no clue what can cause a 5e fault code but just to clarify a fuel evap problem can cause the 5e (secondary-air hot-film air-mass sensor) fault code?

I also monitored my car earlier using my obd reader and I found out that the fault code shows up only during cold start. When I clear the fault code after a cold start, it wont come back until the next cold start. I also noticed that the secondary air pump is only active for 3 seconds during a cold start. Is this normal?

Not sure what vehicle you have, but on my 1998 E36 328 the secondary pump ran much longer than 3 sec on cold start ups. Not sure if that has anything to do with the 5E error, just giving you a data point.

Secondary air pump should run a lot longer than 3 seconds.