Air Mass Meter fault code

[chris233]

940S 1994L B200F Bosch Jetronic 2.4

I have a 1-2-1 code from my fault reader 'air mass meter signal absent or faulty'.

I have disconnected and cleaned the connection plug and checked visually that the small copper wire is intact inside the air inlet tract. After a short run the fault code has not yet reappeared, but it may need longer - Is there any way that I can test the component to see if it is working or indeed faulty?

I have been experiencing problem hot starts recently - i wonder if this could be related?

I know that air mass meters are expensive! All advice and suggestions greatly appreciated!

Many thanks in advance,


Chris

[GavinC]

One way to test it is to disconnect it and see if your car starts and runs differently. On my 960 if I disconnect while the car is idling, the change is immediately apparent. Reputable breakers can be a good source for MAFs and some on the forum have highly recommended e-bay. The things are not cheap via dealers, that's for sure.

To test the Air Mass Meter, first disconnect the air intake pipe so that the meter is not in the air box but still connected to the engine (so that it will still work), run engine, get someone to switch off the ignition while you look dowm the pipe, you should see the hot wire glow red hot, apart from that you can test the air temp sensor but I don't have the test results to hand at the mo. code 121 is a very common code that will show up for all sorts of reasons that are not faults, eg stalling, etc.

[GavinC]

I'm sorry I neglected to mention what may be obvious to you. If your car starts and runs unchanged on disconnection of the MAF, then the MAF is faulty.

[chris233]

Thankyou both for your advice - much appreciated.

Chris