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ATP A Pulled out my MAF sensor today and visibly it looks clean. The MAF itself looks clean too. Nothing in the screen, inside the pipe looks like it's brand new as well. Not a spec of dust. How can I test the MAF sensor to tell if it's working or not aside from just putting in a new one and comparing? Not really into spending $200 if I don't have to. To be specific I'm looking at Volvo part number 8658471. #1 · May 1, 2016 (Edited) Pulled out my MAF sensor today and visibly it looks clean. The MAF itself looks clean too. Nothing in the screen, inside the pipe looks like it's brand new as well. Not a spec of dust. How can I test the MAF sensor to tell if it's working or not aside from just putting in a new one and comparing? Not really into spending $200 if I don't have to. To be specific I'm looking at Volvo part number 8658471. Sort by Oldest first Oldest first Newest first Most reactions #2 · May 1, 2016 Why do you think you may have an issue with your MAF ? The MAF on your car has a very low failure rate. It's a denso sensor, Not the high failure rate bosch sensor. If you have lean/rich codes aka fuel trim codes, It's likely the oil trap that is at fault. To test a MAF you'd need 1 of 2 things, First a scan tool or vida that will allow you to monitor the sensors reading while the car is running, I believe the spec. for this vehicle is about 4 grams of airflow per second. Otherwise you'd need a wiring diagram and a volt meter, Find the signal wire, And see if your voltage changes correctly with increased airflow. #3 · May 1, 2016 Bunch of folks have told me it's probably the MAF, that's why, haha. My scan tool reads 1.2g/s for the MAF while idling, or driving. Never changes, just a solid 1.2 at all times. There are no blockages or even dirt anywhere in the system, and I've triple-checked all of the hoses and lines are tight to rule out a leak, so it's not a lack of actual airflow. I found the voltmeter method but I can't find a diagram for this sensor anywhere. The few links I have found are all dead. Personally I think it's Fuse 35 / Engine Management relay (it's on order, should be here mid-week), because everything happened identical to the other threads who had Fuse 35 issues. 5 codes, all the same as everyone else's, A/C quit at the exact same time as the codes, Fuse 35 blows every time the car turns on. Fuse 35 runs just about every sensor in the car it seems, so it sounds reasonable that the sensor will read wrong until that's fixed. But everyone keeps telling me to check the MAF, so while I'm sitting around waiting for the relay to arrive I figured I'd do that to rule it out. My issue thread: http://forums.swedespeed.com/showth...com/showthread.php?316457-Trouble-accelerating-in-3rd-and-up-06-S40-2-4i-Manual 0 Reply #4 · May 1, 2016 (Edited) You will need to find an EWD somewhere to check the ECM values. I believe if you just google for it with a filter for PDFs, it comes right up. Also, you will probably need a back probe adapter for your meter to check some values. This info differs for turbos vs non-turbo. So this is for a non-turbo. The MAF receives a signal at its Pin #1 through Fuse #35 from Relay #14 and leads to the main 12V source. Pins #2-5 all go to the ECM at A23, A70, A93, and A3, respectively. For 2.4i, the Intake Air Temp. Sensor is integrated into the MAF as an NTC resistor. Here are some specs to check for power @ the ECM harness. If you remove the ECM cable FROM the MAF, with the push clip on the TOP, Pin #5 is on the left, and Pin #1 is on the right. Supply Voltage Values: Pin #1: 5V Pin #2: 12V Pin #4: 5V NTC Resistor Value Check (Check with regards to MAF Sensor, not harness): Pin #1 to Pin #2 = 2.3KOhms @ 68F If those values check out, then move on to check signals at ECM Terminal, or Breakout Box Terminal.

ECM Terminal	Breakout Box Terminal	Ignition On	Idle
A3	A3	0	0
A23	A23	0	0
A70	B10	1V	1.7V *increases with air mass
A93	B33	68F=3.5V 86F=3.0V 104*F=2.5V	"

For a final reference, when the car is at operating temp., AC off, in neutral, idling, and under no load: Mass Air Flow Rate = ~4 g/s #7 · May 4, 2016

mgm7890 said: This info differs for turbos vs non-turbo. So this is for a non-turbo. ... For a final reference, when the car is at operating temp., AC off, in neutral, idling, and under no load: Mass Air Flow Rate = ~4 g/s Click to expand...

What's the MAF rate at idle for the T5 if you don't mind? Thanks Show more replies 0 Reply #5 · May 2, 2016 just leave it unplugged and drive for a bit. is the car driving any different? if it doesnt drive/feel different...your MAF is probably bad. #6 · May 2, 2016 Man I got a CEL a few weeks ago and when I scanned the code it was MAF performance not as expected. I opened it up cleaned it put it all back together cleared the code and it hasn't come back since. Since it's constantly reading 1.2g/s I'd venture a guess that it's plum broke. If you unplug it and it doesn't change then there's a different issue, but it isn't unheard of that these MAF sensors failing. Insert Quotes Post Reply

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