Hey, i was wondering if you could tell me which wire to the ECU is for the o2 sensors. I am installing a a/f gauge and it requires that 1 of the wire be tapped into the sensor wire. There are 3 wires, 1 for ground, 1 for power, and 1 that runs to the ECU to tell the reading. The colors are as follows under the hood. Redw/black stripe, white, & blue. I have a 99 Maxima GXE Cali spec. Thanks.

 

This information comes from the '99 Maxima factory service manual

Front Heated Oxygen Sensor, Left Bank
ECM terminal 121, wire color blue
ECM terminal 51, wire color white

Front Heated Oxygen Sensor, Right Bank
ECM terminal 119, wire color blue with yellow tracer
ECM terminal 50, wire color white

Without disconnecting it, look at the large connector at the Engine Control Module. This monster has more than 100 terminals. Looking at the harness side of the connector, you should see eight distinct groupings of terminals. At the left end you should see a rectangular group of twelve terminals, arranged as three rows with four terminals in each row. Adjacent to this left-most group of 12 terminals there is another rectangular group of 12. Focus on the lowest row in these groups. Starting with the one in the corner they are numbered 117-120, then jumping to the next group they are numbered 121-124. Terminal 119 should have a blue/yellow wire. Terminal 121 should have a blue wire.

Now turn your attention to the right end of this ECM connector. There is a group of three terminals arranged vertically. Adjacent to this group there is an irregularly-shaped cluster of terminals. The second row is numbered 48,49,50,51,... Terminal 50 should have a white wire from the right bank Oxygen Sensor and terminal 51 should have a white wire from the left bank Oxygen Sensor.

 

Which would you say would be the best to connect to? I tapped into the white one (either 50 or 51) i will have to check tomorrow morning. The a/f gauge seems to work, but im not sure if its working the way it should be. Thanks for the help!

 

Ok, I tapped into the white one (51). This is the sensor located right at the front manifold. Right by the valve cover. I will have to check tomorrow morning about the other. I found this wire from the continueity (spelling?) w/ a meter.

 

I'll have to refrain from advising you on this point. I don't know squat about the a/f gauge. Please consult the manufacturer.