Service Engine Soon Light (01 Maxima)

[rather_b_boatin]

Latest update on CEL light, found an exhaust grounding strap not connected. I re-connected it and CEL came on in 80 more miles.

[Nahkapohjola]

Originally Posted by rather_b_boatin

Latest update on CEL light, found an exhaust grounding strap not connected. I re-connected it and CEL came on in 80 more miles.

Sounds weird that strap is off: what is the history of u car... TroubleShootin: The intermittent are the worst to hit...

That strap may or may not have any connection. O2 etc signal level is so small, long wiring, many [oxidized] connectors on the way to ECU that signal can be lost many times over to the resistance and/or radio frequency noise. Btw. That /those sensor harness must have a gnd strap for each: are they connected and connection ok? (dont ask me where they are, the shield gounds should be connected on ECU side, but Nissan does not really follow the rules.)

[rather_b_boatin]

I can check those at the ECU (after I find ECU!). Yesterday I changed the new O2 sensor to other bank, had to modify the plug to fit. (same color wires) 56 miles and no CEL yet, we need to do a long trip to be sure however, not holding out hope. Just for fun I read ohms new to old and old was 1-1.5 ohms higher than the new one, might inc volts a little?? Also noticed that O2 wire that I removed was in a coil, at one point, next to (laying on) an exhaust flange. Fixed that while I was at it. Will keep you posted Nah, thanks for help so far.

[Nahkapohjola]

Originally Posted by rather_b_boatin

I can check those at the ECU (after I find ECU!). ...and old was 1-1.5 ohms higher than the new one, might inc volts a little?? ...

I would guess ECU is in the same place as in the oldies. On some nissans its under driver seat.

The resistance could be pointing to the error, however one ohm difference may be caused by anything. How was it with the other sensor?

My ol max ECU:

[rather_b_boatin]

300 miles so far, no CEL. Fingers crossed.