waybux

The air filter wasn't replaced, just visually inspected. It looked fairly clean but did smell of fuel a little. On the O2 sensor, I was thinking that was the problem initially, so we just did the ecu mode 1 test. I got the procedure from the forum here. It said to put Ecu in mode 1, then see if green led blinks 5 or more times while engine is running no load 2000rpm normal temp. The green led blinks 5 times so I just figured that meant the o2 was working properly. Is there a different/or additional test that you would recommend trying? thank you for your time.

Ok I will try that today or tomorrow and see what happens. Thank you for your reply, I will post what happens.

I am a new member and this is my first posting so I apologize in advance if I did/do something wrong, kinda new at this. My sister has a 89 pathfinder v6 auto, has about 190k miles. Recently the check engine light came on. We pulled the codes in mode 3 of the ECU, it came back to a code 55 (no malfunctions). In Mode 1 (o2 sensor function) the test came back with 5 flashes of green l.e.d. As I have read this should me that the o2 is functioning fine. In Mode 2 (air/fuel mixture) the red l.e.d. didn't come on, as the npora previous post stated this means its more than 5% rich. At this point I am assuming that this is what is causing the check engine light to come on. Oh, tune was just done after light came on, reset light and light continues to come on. Any suggestions or help would be greatly appreciated.