2002 Nissan Sentra CA 1.8L mil lamp on

Car Question:

I have a hesitation problem on this car with mil lamp on. When I scanned for codes, got P0102 maf flow circuit low fault. Installed a new one from Nissan but problem is still there. Suggestions?

ATS Adviser:

If you have a maf sensor code, the best way to check it is to trace the maf sensor wirings. It has 4 wires:

black wire is ground wire
red wire is the 5 volts vref supply
green wire is the 0-5 volts signal supply
white wire (or gray shown below) is the 12 volt supply

You can check these wires if the reading are within range or not. The green wire is around 2.5 volts at idle and should increase when you rev it up. The 5 volts vref wire should stay the same voltage at all speeds. If the vref reading is out of specs, disconnect each sensor with vref supply until reading returns to normal. You can also check the vref supply at the ecm terminal (pin AVC C) to check if the ecm driver is OK or not.

Note:

Shown below is an approximate 5 volt VREF diagram for this vehicle's sensors:

2002 Nissan Sentra VREF Wirings

For more details, you can get a complete wiring diagram for this vehicle from most parts store when you buy parts or get it free online when you join ATS.

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