Turn ignition On.
On all models except Pathfinder, Pickup and Van, proceed as follows:
Turn diagnostic mode selector on ECU fully clockwise and wait until inspection lamps flash. Number of flashes displayed indicates corresponding mode.
Note number of flashes, then immediately turn diagnostic mode selector fully counterclockwise.
3. On Pathfinder, Pickup and Van models, proceed as follows:
Turn diagnostic mode selector on ECU to On position and wait until inspection lamps flash.
Note number of flashes, then immediately turn diagnostic mode selector to Off position.
On all models, when ignition is turned Off during diagnosis, in each mode, and then turned back On again after power to the ECU has dropped off completely, diagnosis will automatically return to Mode I.
For description of modes, proceed as follows:
Mode I (Mixture ratio feedback control monitor A): during a closed loop condition, the green inspection lamp turns on when lean condition is present and goes off when a rich condition is present. During an open loop condition, the green inspection lamp stays off.
Mode II (Mixture ratio feedback control monitor B): during a closed loop condition, the red inspection lamp turns on and off simultaneously with the green inspection lamp when mixture ratio is controlled within a predetermined value. During an open loop condition, the red inspection lamp stays off. The green inspection lamp function is the same as in Mode I.
Mode III (Self diagnosis): in this mode the DTC is indicated by both the red and greed inspection lamp. The red inspection lamp corresponds to units of 10; the green inspection lamp corresponds to units of one.
Mode IV (Switches on/off diagnosis): during this mode, the inspection lamps monitor switch on/off condition of the throttle valve switch, starter switch and vehicle speed sensor.
Mode V (Real time diagnosis): if a malfunction is present during a driving test, the inspection lamps will display the malfunction condition immediately.
READING DIAGNOSTIC CODES
The Electronic Control Unit (ECU) monitors several engine sensors and actuators. If a problem occurs the information is stored in the ECU's memory for retrieval.
The codes are displayed by the red diode on the ECU. The codes are interpreted by the number of times and duration the diode flashes.
The red diode will flash for 0.6 of a second with 0.6 of a second delay between flashes "X" number of times, this will represent units of ten.
Then there will be a delay 0.9 of a second and the red diode will flash for 0.3 of a second with 0.3 of a second delay between flashes "X" number of times, this will represent units of one.
There will be a delay of 2.1 seconds between codes.
For example, if the red diode flashes once and then flashes twice rapidly this should be interpreted as code 12. The codes are displayed in numerical order starting with the lowest and ending with the highest.