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Discussion Starter #1
down loaded a repair manual. Checked voltage readings while running and ohms while off and connecter off. Readings are close to what manual states. It said to check wires going back to ecu. With both connecters off I checked wires with cheap ohm meter set at 20K. From #2 (RG) on MAF it said continuity from 2 to 119 and 120 on ecu side, Mine shows no reading to them but does go to 114 and 115. I went down the line from (#2 MAF connecter)to 4 5 10 13 16 23 24 25 29 42 43 69 70 71 80 82 83 84 85 91 98 106 (ECU side). Meter started at 90.1 then slowly went down to 79.2. On 68 it went down to zero. Does anyone know if this is right? It didn't say anything about getting readings from any except 119 120
 

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I'm not sure where your manual was getting those pin numbers, maybe for a VQ. This is from the Nissan SM for an '06 QR. A streaming scanner will tell you more about what's going on than anything else, generally any engine will read a bit more than its displacement in gallons per second at idle. QR's are generally in the 3 gps range.
 

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PS - The R/G is the power wire, a voltmeter will tell you more about that than ohming things out. You should see near battery voltage at 2, and near battery voltage between 2 and 3. If 2 has power but you see 0V (or a much lower voltage) between 2 and 3, then your ground is bad. The only place you should see a variable voltage (when running) is on 4. There an ohmmeter can help you, you should see near 0 ohms between 4 and 51 on the ECM. If not, the signal wire is open.
 

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Discussion Starter #4
R/G reads 14.3 when its connected and key on. What I was worried about was getting ohm reading when both connecters (ecu and maf) are disconnected on so many terminals. Should there be that many terminals showing an ohm reading coming from #2 R/G to so many others?
 

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Sure, because you're ohming in parallel through all the 12V circuits in the car. Unless you pull all the connectors on a given power circuit, you'll never read infinity. That, by the way, is exactly what makes short-circuit tracing so infuriatingly complicated. The main thing with sensor supplies is making sure both power and ground are good. That's why you measure voltage across the terminals at the MAF, because an "off" reading tells you instantly that something has resistance. Comparing the readings from the sensor +supply pin and +battery tells you whether the drop is on the power side or the ground side. If both power sources read the same to battery ground, but the sensor supply reads low when measured to sensor ground, then you know the sensor ground is faulty.
 
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