Faulty Mass Air Flow Sensor?

Just got back home after full day stranded in workshop. My current ride is a 2009 Cayman with PDK . The car was running flawless until this morning.... The car flashed Emergency Transmission Run warning message after fuel-ing up. The gear shift was very hesitate to either upshift and downshift. Immediately stop the car and restart and the warning light was gone. After driving for another 2 miles or so, the light came back up along with check engine light. Went straight to a reputable workshop locally for quick diagnostic. There were quite a number of error codes thrown, one of the is DME fault - Mass Air Flow Sensor, followed by a bunch of communication related error codes such as PDK fault, PSM, etc. Couldn't recall exactly but i was told that it was due to faulty Mass Air Flow Sensor. The PDK shift point is determined by amount of air flow, claimed by the mechanic. Does anyone encounter similar issue, throwing transmission emergency run warning light & check engine light, becoz of a faulty MAF sensor ?

If you are not under warranty you might try cleaning the MAF sensor with some over the counter MAF cleaner

Tried that. Found quite a lot of oil residue during cleaning. Problem persists. The car was running fine this morning without warning but message flashed again before reaching work place.

Try running without the MAF. The ECU will just default to factory settings. If the problem is still there, you have something else wrong.

Just an update. Future reference for 987-er who encounter same issues... The flashing of engine light, followed by transmission emergency run, seems to be random and intermittent. I suspect it's the Slick 50 Fuel System Treatment i added in the last fuel up. I have just top up another half tank or so with fresh fuel, ok so far it seems. Will continue to monitor.

It's indeed a faulty MAF sensor . Replaced oil air separator as well and CEL has disappeared for few days now since repair.

Hi all, Sorry to reopen this old thread but it seems that I have the same issue mentioned above. I plugged the Durametric cable and it returned the following error codes: 9010: Hot-film mass air flow sensor (MAF), elecrical fault. Value below lower limit value C401 U0401 - CAN fault, engine B1010 HFM: electrical fault. Value below lower limit value Do you think it is the same issue here meaning that I have to change the MAF sensor? Thanks!

Reply to myself. Changing the MAF fixed the issue

Thank you for the update! Did you try to clean the MAF before deciding to change it? I have had several MAF issues on other cars and cleaning the sensor has usually resolved the issue. Just curious.

Ok. will check again. My car is a 987.2 . Thanks

Yeah, you will not see dirt. The actual sensor is buried deep into the housing and it doesn't take much carbon deposit on it to change the reading. Anyway, you fixed it. Haven't done this on Porsche and was just curios how much pain it is.

Much more difficult on a 987.2 compare to 987.1 . My dealer needed 1,5 hour to replace it while you can do it in 10 min on a 987.1

Well, nuts! I cleaned my sensor, but the CEL came back on about the next day, about 30 miles later. OBDII says P1090 (Bank 1 lean). Durametric says 9010, "Hot-film mass air flow sensor (MAF), elecrical fault. Value below lower limit value." The H010 MAF plot looks good and shows airflow increasing with more throttle, but the H030 voltage plot is stuck at 0 with intermittent dips down to -1.1V. I have a 2010 Boxster S PDK and I wasn't able to get my MAF out of the engine compartment to clean it so I just sprayed it in-place, but I need to get it out to replace it. I have a new MAF on that should be here soon, but I have no idea how to get them in/out of the engine compartment. I can't drop it down because PDK blocks it. How have you all been able to get it out? Throttle body? Looks like just 4 torx bolts and I assume an electrical connector that's hidden from view. I was thinking maybe removing the air box, but the workshop manual's step #1 for removing the air box is to remove the engine, hahaha.

I had a similar issue on my CS 987.2 w/ PDK . It started with the transmission flash error, running rough and a variety of codes. It ended up being a bad coil.

Were any of the codes MAF related? I have a coil that misfires occasionally (usually after sitting a week or so without being driven, gives a comm error as well as misfires), but my son is bogarting all my jacks right now so I can't swap it. The MAF code seems pretty specifically to point to a bad MAF, which I've heard reports of it also causing misfires.

Unfortunately I don't recall all the codes that were generated. The code pointing to the coil was a P0302. Good luck...

I missed that our cars have a hot film sensor, not hot wire; hot film style cannot be cleaned and can only be replaced. Replacing my MAF fixed the issues ( OBDII threw a P1090 code, Durametric reported a 9010.) It was intermittant and sometimes caused a PDK error. I was able to get enough clearance to replace the MAF by disconnecting the two corrugated vacuum lines from the manifold by the throttle body. The correction factor readout in Durametric went from about +20% to about -20%. Attempts to clear the Durametric and OBDII codes failed which was worrisome, but the CEL disappeared on its own a few trips after the swap. I just did a full autocross on the new MAF, took FTD, no issues.

Here's another occurrence of the same issue; P1090 and PDK Emergency Run. The car is a 2009 Cayman S with a 3.8L conversion. This one had a wrinkle though, when I wiggled the wire bundle by the connector the MAF data would come and go as indicated on PIWIS (H010). Several of the wires had sharp bends in them just next to the connector so I replaced it cutting off the suspicious parts of the wires. Connector can be found here: Home » Shop » Connectors / Harnesses » Bosch » Bosch 5 Way Trapezoidal Connector Plug for Bosch Pressure Sensor Combined PST-F 1 Connector Kit Ballenger Motorsports Bosch 5 Way Trapezoidal Connector Plug for Bosch Pressure Sensor Combined PST-F 1 Connector Kit (CONN-76140) for only $11.99! www.bmotorsports.com Be careful as the wires for the IAT and MAF are almost identical in color (ask me how I know...). This corrected the varying response when moving the wire bundle but fault code remained. Replacing the MAF with new Bosch unit fixed issue.