I've searched all over the internet and can't come up with a straight answer. Some multimeters are capable of reading DC frequency, but I don't know if mine is or not. If I rotate the dial to Volts AC and press the second function button, it will read in Kilohertz, but I don't know if I'm seeing DC Kilohertz or AC Kilohertz. The MAF sensor sends a DC square wave to the computer. I'm getting a reading of 2.9 Kilohertz when I back probe the signal wire, but I can't see how that's possible if in fact the meter is set to AC frequency. The service manual says I'm supposed to have a minimum of 1.2 Kilohertz going to the computer. Anything less than that, the computer will throw a P0102 DTC. If anybody is bored enough and doesn't mind finding out if my meter is capable of ready DC frequency, I'd appreciate it. The meter I have is a Fluke 77-IV. Thanks fellas.
Looking for a multimeter that reads DC frequency
- Thread starter Merkava_4
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DC by definition doesn't have any periodic components. There isn't such a thing as a DC square wave, a square wave is a square wave.
What you're looking for is a meter that will measure frequency. Looking at the Fluke 77-IV, it does measure frequency. You'll want flip it to the second position (for VAC), then hit the yellow button to switch to frequency. It measures frequency, regardless of waveform (sinusoid, square, sawtooth, etc).
Edit, I just re-read and that's exactly what you did. Sounds like you measured it exactly as I would have suggested. Your measurement sounds right to me. Is it throwing a code? It sounds like it's working within limits.
What you're looking for is a meter that will measure frequency. Looking at the Fluke 77-IV, it does measure frequency. You'll want flip it to the second position (for VAC), then hit the yellow button to switch to frequency. It measures frequency, regardless of waveform (sinusoid, square, sawtooth, etc).
Edit, I just re-read and that's exactly what you did. Sounds like you measured it exactly as I would have suggested. Your measurement sounds right to me. Is it throwing a code? It sounds like it's working within limits.
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Hi Edward! Thanks for checking on that meter.
It did originally throw a P0102 code, which means the computer didn't like the frequency it was getting from the MAF sensor. As it turns out, I had a bad pigtail at the MAF sensor. When the engine would flex in its mounts from engine torque under acceleration, it would pull on that MAF pigtail and momentarily cut the frequency signal to the computer. I had good power to the MAF connector, good ground, and a good signal wire. A buddy of mine suggested that I wiggle the MAF connector with the engine running to see if the engine would start bucking and jerking; sure enough, it did. I put a new pigtail on it tonight and hopefully the check engine light will stay off. Incidentally, those engine harness wires are very difficult to strip when they're old and hardened up. The new pigtail was a breeze to strip compared to the old harness wires. I'm thinking it may be time for a new engine harness.
It did originally throw a P0102 code, which means the computer didn't like the frequency it was getting from the MAF sensor. As it turns out, I had a bad pigtail at the MAF sensor. When the engine would flex in its mounts from engine torque under acceleration, it would pull on that MAF pigtail and momentarily cut the frequency signal to the computer. I had good power to the MAF connector, good ground, and a good signal wire. A buddy of mine suggested that I wiggle the MAF connector with the engine running to see if the engine would start bucking and jerking; sure enough, it did. I put a new pigtail on it tonight and hopefully the check engine light will stay off. Incidentally, those engine harness wires are very difficult to strip when they're old and hardened up. The new pigtail was a breeze to strip compared to the old harness wires. I'm thinking it may be time for a new engine harness.
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