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240 3-2-2 Code, MAF/AMM


Jun 4, 2012
Upstate, NY
Car: 1990 240 B230F AW70

Wagon is showing a 3-2-2 code, which to my knowledge indicates a "bad MAF"
I think the car might also be running lean at the moment.

I've tried 5 different MAFs (3 new, 2 used) all of them have a rough idle (some less than others) and they all throw a 3-2-2 code.

Could it be an electrical wire somewhere else in the system rather than the MAF itself?
How are the contacts in the connector? I would also check the fuel ecu for being a 561 unit. They make false codes and don't run quite as smooth as the 951 version. Also while you're checking the fuel ecu. Check the connector contacts for the ecu. I've had them push out of the contact area of the connector. Needed to be snapped back into place.
That's a code for the maf hot-wire burnoff function not working. It has a dedicated ECU-to-MAF white wire (ECU pin 8 to MAF pin 4). I'd start by checking the white wire at the MAF connector as Dave suggests ^^^.
You gotta drag test the terminals with the proper test probe, or make a probe made from an old component. I'd resistance test and voltage drop test the circuit. If it tests good try another ECU.
You can use a test light to confirm whether you are getting burn off. Backprobe the connector on the maf on the burn off wire and see if it briefly turns the light on about 45 seconds after you shut the engine off.
Well, after testing the original MAF, it started working again....new-made MAF still doesn't work.
The mystery continues and I'm pretty confused, but I'll quell my curiosity until it rears it's head again.
Did you check the terminal tension (drag test)?

Fretting can cause a poor connection. Cycling the connector can be enough to knock off some of that microscopic corrosion.

Always backprobe if you don't have the proper test probe. You can get away with light front probing as long as you don't go stuffing a lead in there and spreading the terminal causing poor terminal tension.
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I removed the rubber cover from the top of the connector to test the terminals and checked that they were seated properly.

It recently stalled when I stepped on the gas pedal from idle at a traffic light.
Started right on up again and have not been able to repeat the issue.
The car is now throwing a 2-3-2 code (too rich/lean at idle).

Is this connected to the MAF, or something else? (O2 sensor was replaced last year as well as many intake hoses)
A 232 code was the fake code that a defective 561 ecu would set in my mothers 90 245. If the code is for real then it's usually caused by intake air leaks like a bad intake gasket, the hose from the mass air sensor to the throttle body, or a split vacuum hose somewhere.