I Recently had my car scanned on a friends of mine computer. It pulled a dtc 48 for a faulty maf circuit. He told me it was the maf but before going out to buy a new one I decided Id check to see If i was getting the right voltage. According to my haynes manual the pink wire is supposed to be roughly 12v and the yellow is supposed to reading 5v. Im getting 12v off the pink wire and im getting only 3.59 volts off the yellow wire with the key on. I checked the yellow wire right off the pcm connector (b19) too and still 3.59v. My question is do i need a new PCM or just a new maf like my friend said?

 

Shoebox has the 95 PCM pinouts on his website, with voltages for each circuit, key on, and for engine running. MAF signal wire - key on 5.0V, engine running 4.3V & varies. But the signal from the MAF sensor is not voltage dependant. It is a frequency signal (Hz) riding on the yellow wire voltage. With the engine idling, you should see about 2,800Hz on the wire. That will tell you if the MAF sensor is working.

 

As Fred said above the MAS signal to the PCM is a frequency... The +5v test is for the reference voltage from the PCM to MAS and can only be checked with the MAF harness DISCONNECTED. MAF unplugged, ignition on, engine off you should have 4-6 Volts between the yellow wire pin A in the harness and ground. This is a reference voltage from the PCM pin B19. If it's OK all it says is that the PCM and wire to MAS is not open or shorted. You could try vibration or wiggling the wire to make sure connections are tight. Same for +12 pink wire on harness pin c and harness pin B black ground.