1996 Nissan Truck - AirFlow Meter

SLBRUNK2

MEMBER
1996 FORD

I have a 1996 Nissan truck that is faulting a code for the air flow meter valve. I have changed this valve which cost $400 from the dealer. I am a fair mechanic and even earned my living for a couple of years working in a shop. However, after replacing the air flow meter which is on the side of the throttle valve, I still get this code. I have read up as much as possible on ideas and have not found one that has helped me to resolve the issue. Any ideas on where I can look and how I can diagnose any further? I can't really afford to take this to a dealer to fix right now. The truck runs fine and is getting an average of 21mpg. There are no other issues at this time.

3 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Try the TPS-sometimes the PCM can be fool by its signal and triggers the AFM. That's if the wiring and pcm okay.

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Saturday, January 20th, 2007 AT 7:36 AM

SLBRUNK2

MEMBER
2 POSTS

Thanks, I will look into that. I assumed it was most likely something with the circut causing it fault the air flow meter when it appears it is not actually the AFM. I will try replacing the TPS and see what happens.

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Saturday, January 20th, 2007 AT 10:03 PM

RASMATAZ

MECHANIC
75,992 POSTS

The MAF sensor was replaced but the code kept coming back. The MAP sensor was again replaced and the wiring checked, but the code continued to reappear. The real problem, it turned out, was actually a bad throttle position (TPS) sensor. On this particular vehicle, the OBD II system uses the TPS voltage setting to check the calibration of the MAF sensor. Because the TPS sensor

wasn't reading the proper voltage at idle, the OBD II system thought the throttle was open, but the MAF wasn't reading enough air flow. So it set a code for the MAF sensor when, in fact, a bad TPS reading was causing the glitch

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Sunday, January 21st, 2007 AT 1:19 AM