Maf???
Posting Guru
Joined: May 2003
Posts: 1,666
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From: Sunny tourist infested FL
You need a true RMS Multimeter to perform the frequency test on the MAF sensor such as a Fluke 87 multimeter. To measure the frequency output of the sensor at the electrical connector simply use a T-pin and gently slide the tip alongside the signal wire toward the metal terminal inside the plastic connector. DO NOT PUNCTURE THE INSULATION of the signal wire itself with the T-pin as this can indeed cause a short! Then use either an alligator clip attachment for your digital multi-meter or a jumper wire with alligator clips at both ends to attach to the T-pin and the positive (+) meter's lead. Turn your meter on to DC volts and select the Hz button for frequency and duty cycle. On the Fluke 87 Digital multimeter the Hertz button is located under the "Hold" button and is marked as "Hz". Once the display comes up and is reading in kilohertz (consult the instructions that come with your multimeter to get it to display this), with the engine running at idle, measure the frequency across the signal wire on the MAF sensor by touching the negative lead of the meter to ground. With the engine at idle you should get a reading of around 2.37 to 2.52 kHz, which is the normal range. Hope this helps!
Junior User
Joined: May 2008
Posts: 76
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From: Beavercreek, Ohio
I would not recommend driving without the MAF hooked up. The powertrain control module needs the airflow information to adjust your spark advance properly, otherwise engine damage can occur if the computer allows the engine to go into detonation or cause pre-ignition problems due to a too rich/too lean fuel mixture setting. The PCM computer is what controls all of these engine operating perameters and solely relys on all its sensors functioning properly to provide optimum engine performance.
Junior User
Joined: May 2008
Posts: 76
Likes: 0
From: Beavercreek, Ohio
It can be a contributing factor as to why the PCM has switched into the fail safe mode, but its not likely to be the only cause. I would be looking at the PCM itself, and see if there are any stored DTC codes (diagnostic trouble code). If a serious DTC code is set and stored in its memory, the PCM will often switch to the fail safe mode. The PCM itself has four basic functions; input, processing, storage and output. If any one of these functions is seriously disrupted in any way the computer will switch into fail safe mode.
If the computer checks out okay then I would be looking at the PCM's primary sensors, associated wiring, etc. Hope this helps!
If the computer checks out okay then I would be looking at the PCM's primary sensors, associated wiring, etc. Hope this helps!
Junior User
Joined: May 2008
Posts: 76
Likes: 0
From: Beavercreek, Ohio
You can use the negative post of the battery or hold the meter lead onto the engine block, since its grounded.
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