karayj

I have tested my car again because the check engine light when on after replacing the o2 sensor when it read it was bad. (rear passenger side)Now I get a reading that all 4 are bad so I replaced the computer under the dash and it still reads all 4 bad. I know all 4 cannot be bad because I replaced the rear driver’s side 6 months ago. Has this ever happened to anyone out there> I don’t want to replace all 4 just to find out it will still read all 4 bad because it was something else cause the false read and be out 200.00.

smj999smj

Some of the 3.3L engines had issues with a bad ground for the engine harness at the intake plenum that was addressed in a TSB. The bulletin instructed how to test for the bad ground and also have details of a subharness available to correct the problem, which basically added ground wires between the right cylinder head and the plenum ground points. You don't mention what year PF we're working on, so I can't tell you if the TSB applies or not to your vehicle. I'd be more than happy to send you a copy of the TSB; send me an e-mail at smj999smj@hotmail.com and put "RE: Pathfinder ground TSB" in the subject line and I'll get it out to you. I wish I could have let you known prior to you replacing the ECM!

karayj

All the help via email you gave me was on target. The #25 fuse was blown because at on time I replace a bad o2 sensor and crossed the wires. I posted a message for help asking if crossing the wires would cause a problem because the eng light was still on. No one answered not a soul. Then I posted a new message because I replaced the eng computer and still read 4 bad o2 sensors.
You are the smartest guy on this board and any one needing help look for this guy he know his sh*t.

smj999smj

Well, thanks and I'm glad we got her straightened out. Sorry I didn't hear about your problem before you went for the ECM. It's a pretty rare circumstance when a Nissan ECM fails providing it doesn't get wet or someone doesn't cross-jump the battery.