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View Full Version : Need quick check on MAF data before I buy new one...



AggieBlake
07-18-2018, 10:31 AM
Need a quick double-check before I drop $150.

Car: 2005 e46 330i 6-speed, 115k miles.

SES light is on, code P0102. Cleared code, but it comes back on within 3 miles or at restart.

Idle is steady, but lower than expected. Throttle response is also less than expected, and the throttle is completely unresponsive if brake pedal is depressed even in the slightest.

Connected OBD2 scanner to read "Mass Air Flow Rate" and "Fuel System Status"

MAF rate is 0.0 lb/min with MAF unplugged and a constant 0.01 lb/min with MAF plugged in, regardless of throttle position or engine revs. I do not know what the OBD2 value should be when the MAF is working, but I'm sure it should change with rpm/throttle.

Fuel System Status states that it is using oxygen sensors because "system A" is open loop rather than closed loop.

I have felt around for vacuum leaks or cracked hoses to no avail, and don't know if a vacuum leak could explain the bogus MAF rate reading or open loop condition. Note that all intake boots are 6-months old.

Based on all this data, I assume my MAF has gone bad. Is that correct? Or could there be a short in the harness connected to the MAF? I have a multimeter - can anyone tell me what voltages or resistance values to expect in the harness wires? I couldn't find a good description online.

Thanks for the help!

Vas
07-18-2018, 11:58 AM
Sounds like a dead MAF sensor to me.

What is the IAT reading?

AggieBlake
07-18-2018, 03:11 PM
What is the IAT reading?

Will check tomorrow. The battery voltage was low, and it's over 4 years old, so I'll switch it out tonight and then retest everything.

AggieBlake
07-29-2018, 03:18 PM
It was the MAF. Bought a new VDO unit for $220 from Bav Auto, popped it in and it fixed the problem immediately.

danewilson77
07-29-2018, 03:26 PM
It was the MAF. Bought a new VDO unit for $220 from Bav Auto, popped it in and it fixed the problem immediately.I've got VDO as well. Been a champ thus far. About 1.5 years old. Maybe 20K miles.

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