Quote:
Originally Posted by DieselPaul
My 2006 E320 CDI has the check engine light on, hooked up carsoft and it has codes:
P0102 - Mass or Volume Air Flow A Circuit Low
P0101 - Mass or Volume Air Flow A Circuit Range/Performance
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Without a diagram in front of me, P0102 tells me that the sensor output voltage is zero at all times or, if the system has a very sophisticated diagnostic routine, output is lower than expected even at higher air flows.
Generally, the MAF output is a few 10ths of a volt even at zero air flow so the computer knows the circuit is intact. The output may stop just short of 5V at high air flow so the computer knows if the sensor has not failed and gone full scale. I'd hang a volt meter on the output.
The P0101 is likely just a result of the first code.
If this ( Bosch ) sensor is like the 97 era diesel / gas cars, there are 2 voltage sources required to make the sensor work, 12V from a fuse to power the MAF circuit and 5V from the computer that becomes the variable MAF signal output.
Attached is a file I came across a while back
www.auto-consulting.it/DWN/Mass_Air_Flowsensor.pdf