07 S60 2.5T, Maf reading seems fine, but sets P0101 code.

importCar · Post by **importCar** » 29 Nov 2014, 10:14

Hi, thanks for coming in. From following data when code us triggered, is the problem with the MAF sensor or leak in the air intake path?

Freeze frame information:
------------------
Fuel Status = 0 byte
Engine Load = 22.745 %
Engine Coolant Temperature = 190.4 °F
Fuel Trim Bank 1 Short Term = -13.281 %
Fuel Trim Bank 1 Long Term = 7.031 %
Fuel pressure = 43.511 psi
Engine RPM = 1,559.5 rpm
Speed (OBD) = 45.36 mph
Timing Advance = 38 °
Intake Air Temperature = 71.6 °F
Mass Air Flow Rate = 11.25 g/s
Throttle Position(Manifold) = 18.431 %
Run time since engine start = 537 s
Barometric pressure (from vehicle) = 14.359 psi
Voltage (Control Module) = 14.398 V
Engine Load(Absolute) = 30.196 %
Commanded Equivalence Ratio(lambda) = 1
Relative Throttle Position = 6.275 %
Ambient air temp = 71.6 °F
Absolute Throttle Position B = 17.647 %
Accelerator PedalPosition D = 14.902 %
Accelerator PedalPosition E = 14.902 %

draser · Post by **draser** » 29 Nov 2014, 20:24

Can you post readings at idle as well? Not sure how much maf should read at 45mph. If anything the short fuel trim shows a rich condition, but you may have pressed the pedal while taking the readings....

importCar · Post by **importCar** » 30 Nov 2014, 08:06

Thanks, draser.

I will try to capture one later when i go out. When the car idle smooth, the MAF reading is about 3.5g/s, give or take. But when idle become rough, the reading could be between 1.x to 5.x. I've seen STFT to reach positive 25 and/or negative 25.

draser · Post by **draser** » 30 Nov 2014, 10:00

That's about what I get on mine for maf at idle, about 2.6 g/s. Fuel trim jumps like that are normal, provided it averages out around zero at steady state. Best is to take a reading at idle then a second at 1500-2000 rpm steady.

importCar · Post by **importCar** » 01 Dec 2014, 08:43

Car has been running good for the past two days. Code is still there but check engine light is off. When it runs good, all things look good. For this kind of intermittent fault, is it more a electrical (sensor) or mechanical (leak) problem?

I will try to find a way to log the car info to capture to bad moment. Any suggestions?

draser · Post by **draser** » 01 Dec 2014, 11:12

Readings look good, you may have an intermittent maf, there was a post on that just recently. I'd open the connector for a visual inspection, spray some contact cleaner in there and see what transpires.

importCar · Post by **importCar** » 01 Dec 2014, 19:58

Captured these bad stft cases. It seems the ecm decided to hold stft. The car is cold. One thing i should mention is when start, engine did not idle at high speed as it normally does. Noticed this several times, each time, ECM is likely to set 0101 code.

BTW, when STFT started moving, check engine light went on. Codes are P0101 and P2188.

draser · Post by **draser** » 02 Dec 2014, 07:05

With engine cold the ecu will enrich the mixture if coolant sensor operates correctly. When that happens the stft will show positive like your reading. I would try cleaning the throttle body even though your car is 2007 but you may have high miles? Again, I'd also check connectors for maf and etm.

draser · Post by **draser** » 02 Dec 2014, 09:15

There's a post on Volvo Forums where this guy having a 2007 S60 experiences these 2 faults and your car's symptoms. Post is called P2188 and P0101 and my fix, since he was kind enough to post all of his saga. He ended up replacing coil packs to fix this. He was not getting misfire codes either.... Based on his experience I'd look at plugs, air filter, coil packs. See which plug looks smoked...

importCar · Post by **importCar** » 02 Dec 2014, 10:22

Great. I will check this out. A lot of home work

Thank you so much.