e60eric

2010 BMW 528i 85,000 miles


Recently the CEL came on and I went to and got the code read as P0442. I searched the forum and found the simple first step is to tighten the gas cap, which I did, but the CEL stayed on. Then I replaced the gas cap but the CEL stayed on.


Before I go any further, has anyone successfully diagnosed and repaired their vehicle after getting this code? Any tips?


Would the CEL go out automatically if I had fixed the problem with the gas cap?

bmwknight

My dad's 2008 528 is having the save issue. P0442 code, he replaced the gas cap and it's still there. I can't seem to find much helpful info online so far - please let us know how to fix...someone! Thanks.

txag_530i

It might take a few miles and/or engine cycles to clear the code.

e60eric

@txag_530i, thanks for the clarification. I figured that was the case. So, unfortunately, I haven't fixed mine since the CEL is still on after a couple of weeks of daily driving.


I'm not too familiar with the evap system, but I found one thread that directed me to the right rear wheel well. I will rip it off and see what I see.


But really, no one has run into this before?

txag_530i

I'd recommend getting a someone to scan the car for the BMW-specific codes. It good be a lot of things from a gas cap to a leak somewhere in the vacuum lines.

Luie

Sub'd for same issue...

seanjordan20

Make sure you did not get a cheap aftermarket one. I had this issue once and after the second fill up it went away. The correct one only costs $20.

550sport87

If p0442 is the only code in the system, a generic obd scanner will clear it. Depending on what you're driving profile is like, it might take quite a while to reset the light. Certain vehicle parameters have to be seen for it to do a self check of the evap system. Same thing goes if you clear it, it might stay off for days or even weeks before the code returns. Those are probably the hardest codes to diagnose because you're chasing a leak of air. So without a smoke machine you could spend days, weeks and hundreds of dollars replacing parts and never find the actual cause.

DavidF

I recently battled this issue as well. I think my problem was a faulty gas cap (did not replace). The cap became hard to tighten, so my kids and wife never tightened it properly and sometime I did not as well. I also, checked the DTM (?) pump and bench tested the motor and solenoid...all seemed fine. Upon reassembly and testing, I would actually get a "tighten gas cap" message on the screen. Turns out I forgot to reinstall one of the tubes into the charcoal canister. Then, I lightly greased the seal on the gas cap. Now the cap is easier to tighten properly and no more error messages. No parts replaced.

Just wanted to relay my experience with this issue. Another item to check is the tank venting solenoid located under the hood (on the engine).

david888

Hi,
I'm having the same issue. Were you able to figure that out?
Thanks in advance