Howdy, I have a 1991 Saab 900S and I think something is a little funny with the air mass meter. I am hoping to get some advice.
The check engine light comes on for about a second or two periodically. Sometimes this is accompanied by the engine stumbling for a split second, sometimes not. I checked the check engine codes and the first one is 12231 (no rpm signal) which is normal, since the engine is off. The next code is 12221 (no signal from air mass meter), which I why I think that's where the problem is. The third code is not listed in the Bentley manual (as far as I can tell), it just repeatedly makes long flashes. I'm not sure what this means. If I cycle it again it starts again with the no rpm signal code and repeats.
So I followed Bentley's instructions for checking the air mass meter. I unhooked it from the air filter, ran the engine above 2500 rpm and then shut it off and watched the wire glow red for a second (burn off). According to the manual this means that the air mass system is probably working fine.
Does anyone have any suggestions or experience with this problem? I hate to put a new part in there if it isn't the problem (the meter is very expensive). I should say that I got a new air mass meter at
118k. It only lasted until 132k and was replaced under warranty. I'm now at 180k. Is 50k the expected life of this part? Is it sensible for the failure to be so intermitent and short lived?Thanks, mark