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[josh_s13]

Is the MAF output signal 5V from ground or 5V across the MAF high and low terminals? The 12.8V on one pin and 12V on the other would leave 0.8V across the resistive element of the MAF. Which is in the ballpark of correct.

[josh_s13]

If you fried the ECU, odds are that white wire would have gone to ~12V or 0V. Either shorting or opening the MAF's circuit. 4V would indicate that it did not cause catastrophic failure, but without seeing the ECU's schematics it would be hard to tell for sure.

[zack11122]

Originally Posted by josh_s13

Is the MAF output signal 5V from ground or 5V across the MAF high and low terminals? The 12.8V on one pin and 12V on the other would leave 0.8V across the resistive element of the MAF. Which is in the ballpark of correct.

That's correct but why would black/white be reading battery voltage? 14v with alternator running. Is that the power wire?


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[josh_s13]

The black and white wire comes from a fuse panel through a relay controlled by ECCS. Yes, It is your power wire.

[zack11122]

Black is ground. But I'm getting crazy resistance from battery ground to it.


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[josh_s13]

http://www.nicoclub.com/FSM/240sx/19...general/EC.pdf

check out page 96. The black connects to pin 17 on the ECU. If you measure resistance from black at the MAF to ground you are going through the ECU. For what it's worth weird resistances reading can come from measuring across capacitive and active devices. If the resistance "ramps" up or down then you are probably measuring across or through a capacitor. If switching the leads results in different, but stable readings then you are looking at a semiconductor. If you are at ground you should see a stable 0 ( minus lead and contact resistance).

[josh_s13]

You should have had 1.2V from the white wire to ground when you had the car running. Check continuity across the harness from MAF to ecu. Check to make sure you have good electrical contact at the connectors. Triple check all ecu grounds. Reset the ecu and run the car. Check codes. If all that didn't fix it, swap the MAF. If you are still kick an MAF code, then replace the ecu.