MAF sensor difference?

[Bad Brian]

To all Soob gurus, my 98 OBS would start but not run more than 5 mins. I got the code P0102 for MAF low input. My original MAF sensor is #22680 AA160 A36-000 R60 made by Unisia in Japan. My harness has a 3 wire connection but the original sensor has 4 prongs. I have acquired a used sensor #22680 AA160 J A36 000 RA0 by Autecs in the U.S.A. which came with the harness connector attached. It is a 4 wire connection and the "new" sensor has 5 prongs! I do not understand how or why but the car is running fine with the substitute sensor in place and no new codes. I have not gotten enough driving in to cycle through all the diagnostics yet. There is also another Unisia version out there with a slightly different part #, #22680 AA160F JA36-000 RA0, also 22680 AA160 A36-000 R60.

 

Does anyone know why the # differences and what about the 3 vs. 4 wires and 4 vs. 5 prongs?

Edited March 15, 2010 by Bad Brian

[idosubaru]

It appears 1991-1999 Legacy and Impreza MAF's all have that same part number you listed. Interesting indeed that it has an extra prong.

 

Maybe they're interchangeable but the extra wire is for some oddball engine - like the Turbo models or something?

 

Does your connector have a blank or a pin at that 5th prong?

Same question for the harness that came with it - of course that probably does.

[Bad Brian]

Grossgary, I just came in from the cold after walking the dog, happy to be in the warmth and then I saw your post! So it was back out to the tundra to look things over!

 

The connectors are identical in both cases. From the harness side there are 5 ports in each connector and the wires either enter each port traveling thru a foam(?) plug OR the port is filled by a solid foam plug in the spots where there is no wire. Numbering the wire locations from engine outward toward the fender my Impreza has wires in ports 1,3,4 but not 2 or 5 however there are sensor prongs at 1,2,3,4. The replacement sensor has prongs at all 5 spots but the harness that came with has wires at 1,2,3,4. So neither connector utilizes the #5 spot. Also the wires on the 2 connectors are not consistent as far as what color goes to what spot either!

 

I did wonder about the turbo possibility. I only know that I use 3 prongs, somebody uses 4, somebody uses 5!

[Legacy777]

The 5 wire MAF sensors are only needed on the first gen legacy, 90-94. This is because they used two different types of MAF sensors. The extra two pins were a reference voltage from the ECU and a ground. This extra pin being grounded was like a switch. If the incorrect MAF sensor was used the ECU would know and illuminate a CEL.

 

This diagram may help show this

http://www.main.experiencetherave.com/subaru_manual_scans/FSM_Scans/MAF_testing1.jpg

 

 

All you really need is three wires, power, signal, and ground

[Bad Brian]

The 5 wire MAF sensors are only needed on the first gen legacy, 90-94. This is because they used two different types of MAF sensors. The extra two pins were a reference voltage from the ECU and a ground. This extra pin being grounded was like a switch. If the incorrect MAF sensor was used the ECU would know and illuminate a CEL.

 

This diagram may help show this

http://www.main.experiencetherave.com/subaru_manual_scans/FSM_Scans/MAF_testing1.jpg

 

 

All you really need is three wires, power, signal, and ground

 

So are the 5 pins older or are they replacements for a broader spectrum of years? Or maybe either is possible depending on the particular part. The 5 pin clearly works for me, but my OEM one could not have been used on older cars.

[Bad Brian]

bump

[Legacy777]

So are the 5 pins older or are they replacements for a broader spectrum of years? Or maybe either is possible depending on the particular part. The 5 pin clearly works for me, but my OEM one could not have been used on older cars.

 

The 5-pin was just used for the first gen Legacy, nothing more. You can use the older 5-pin MAF on the newer cars without any problems. You can't use the newer 3-pin MAF on the first gen legacy, which requires the 5-pin MAF.