2001 V70XC - yet another MAF issue...

Post by **xHeart** » 06 Nov 2014, 09:14

Does MAF fail incrementally?

I had sudden engine OFF issue while car is moving, but it will restart right back.
After clearing the code, the MAF Low Flow returned on VIDA.
So I chose to thoroughly clean the airbox, hoses, and the filter.
Then removed the MAF sensor from the housing and cleaned it well with CRC/MAF spray cleaner. Let is dry overnight. The code disappeared, and the car ran fine for next 1600 miles.

The sudden engine OFF symptom has returned, so is the MAF Low Flow code.

Would you replace the MAF sensor? What about the wire/connector that plugs to MAF?
This part http://www.ipdusa.com/products/6581/110976-maf-mass-air-flow-sensor

Post by **precopster** » 06 Nov 2014, 10:42

Yes recently the MAF on my '98 V70R was switching on and off. Replacing it solved the issue. I checked wiring to MAF which had constant power.

SweedSpeed · Post by **SweedSpeed** » 06 Nov 2014, 16:46

I've had similar issues, resolved by replacing MAF sensor. Do check the current from the wiring first.

Post by **xHeart** » 07 Nov 2014, 07:58

Would DiCE show current flow?

Post by **precopster** » 07 Nov 2014, 13:32

Dice shows air flow at idle or other speeds which should read around 14kg/hr at idle. You can do the same thing with Torque application however it reads in g/s.

Post by **xHeart** » 08 Nov 2014, 05:47

Helpful!

I will use Dice to check the MAF value at idle with existing MAF sensor. IF low flow, I assume it would show less than 14kg, right?

Does Low Flow affect short term and long term fuel trim? Will checking LTFT/STLT verify MAF performance?
New MAF is on its way.

Post by **xHeart** » 11 Nov 2014, 10:49

The MAF ECM-1300 Low Flow value is 11.3 - 12.4 kg/hr at idle.

draser · Post by **draser** » 11 Nov 2014, 12:00

Fuel trims are driven by the front o2 sensor. The MAF operation should corelate to ETM's, i.e. the flow signal magnitude needs to be proportionate to ETM feedback signal going to ecu. Would be nice to have a chart of kg/hr flow vs. volts of feedback from ETM. Not sure if Vida Dice sees the feedback voltage - I'd buy it for that feature alone.

Post by **xHeart** » 12 Nov 2014, 08:41

Interesting.

CEL is on.
After "Updating" Vehicle Communication over DiCE, it is pulling two ECM related trouble codes, one for the Front O2 Bank 1, and one for the MAF low flow.

I will post LTFT and STFT values after the next read.

The new MAF will arrive today.

Post by **xHeart** » 16 Nov 2014, 07:27

New MAF installed Friday night. The Vehicle Communication is not showing any ECM error since.

Here are the values at 640 idle engine speed, 24 hours after installing the new MAF -- a day of normal local driving, a dozen short trips.

DiCE was reading ECM error in following three, not now.

- MAF/no ECM error: starts at 30.x kg/h and then lowers to 12.2 - 12.4 kg/h at 640RPM
- Front O2 Bank 1/no ECM error: 1:00v (Rear 02 Bank 1: 0.45v)
- Brake Pedal Sensor/no ECM error: 3.04v