Can I take a Bosch air mass meter numbered 00280212007 from the junk yard and replace the one in an '89 240 numbered 00280212007 (also Bosch) and expect it to work?
They look the same!
Many Thanks.

Maybe I'm blind, but aren't those numbers the same? In any case, I believe it's the last three digits that distinguish the AMMs. You can't use an "007" from an earlier car on an "016" equiped later car.

Thanks. Yes, I meant 016. So my search will continue for the right AMM.

If you're stuck right now the -007 AMM will function reasonably in LH2.4. It is pin compatible-- the only ill effect I've noticed is a slight performance hit and I don't know about emissions. Of course the mixture pot is not used by the LH2.4 circuit in your 89.

This does not work backward to LH2.0 (83-84) - those AMMs are not pin function compatible.
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Art Benstein near Baltimore

Hi Art, I posted something a few days ago.

I want to test an AMM that is not on the vehicle. I know the Bentley book tells you how to test when it's on the car but do you know a way to do some continuity test or an Ohms reading to know whether This AMM is a good unit that I should hold onto?
I guess I could put it in the car and give it a go but it would be more convenient to just Buzz it out.
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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me

The Bentley tests (also Haynes and Volvo) I've seen are resistance checks off the car which I believe to be next to useless. They certainly don't prove you have a good one.

There's a way to weed out complete duds, by applying power, measuring output and varying air flow-- not exactly "buzzing" it out, but it makes for a go/no-go test, just short of a calibrated airflow test. You'd need a good bench supply-- they draw a bit more than one amp, and a hunk of old harness. It helps to have a number of samples too, so you can draw your own conclusion about baseline output voltage with no air flow-- the usual thing to go wrong with them.

The pick and pull nearby wants $45 for an AMM with a you-bought-it guarantee, so I'd take a compact power source like an old bagphone battery and a multimeter to check function before selecting one from there to own. There's still a chance, even checking baseline, that gain, which sorta translates to acceleration, might be off, though I haven't found any like that.

Much easier to check it on the car-- power source, harness plug already in place. You don't even have to pipe it up, just stick the connector on, turn on the ignition, and see how it responds to a little air movement by backprobing the output wire.
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Art Benstein near Baltimore

And your '89 has Bosch LH 2.4 injection and so SHOULD have the 016 AMM. 007 is for the earlier LH 2.2 cars.

At least, I have never heard of an '89 240 that isn't 2.4. The easiest way to tell would be that if you have the OBD diagnostics box, you have 2.4 and so need an 016 AMM.