Hi everyone,
My J30 max seems to be using quite alot of fuel these days. Thought i might check the ECU for codes and check in Mode 1 to see if oxygen sensor is working ok. ECU showed no codes (55). I started the car and then put it into Mode 1 with the engine running (fully warmed up, idling) there was no flashing green led at all (think it is supposed to flash 5-10 times in 10 sec). Does this mean that o2 sensor has had it? Or have I not followed the proper procedure?

 

Were you revving the engine at 2000 RPM? The FSM says, without going into diagnostic mode, if you run the motor at 2000 RPM for about 2 min the green light should start blinking. Or skip the wait and go straight to Mode 1 as you were doing.

 

No I wasn't revving at 2000rpm. I thought that the procedure you mentioned was to test the circuit.

 

It checks the health and circuit of the O2 sensor.

You should also try Mode 2 (fuel ratio check) to see if you are running rich.

 

I'll try that thanks alot.

 

Ok this might sound stupid but do you have to select the mode on the ECU BEFORE starting the car. When I have the engine already running and then select mode - the LEDs do not flash. But when i have the ignition on, select the mode and then start the car I seem to get a result. Anyway doing it this way -

In mode 1 I get about 5 flashes of the green led and then nothing after that

In mode 2 I get about 5 simultaneous flashes of red and green together and then nothing after that.

With engine fully warmed up and running at 2000rpm I get regular flashing of the green LED.

Does this all indicate that the oxygen sensor is ok?

I cannot for the life of me get the connector apart to do further tests with a mulitmeter. It seems that maybe someone has broken the release button off it or something.

 

which connector? the one to the ecu has a bolt holding it secure

not sure on the modes,maybe translated instructions from japan

 

The connector for the 3 wire lead that runs from the oxygen sensor.