Diagnostic Trouble Code

Wiring Diagram:

CIRCUIT DESCRIPTION
ECM monitors oxygen concentration in the exhaust gas which has passed the three way catalytic converter by HO2S-2.

When the catalyst is functioning properly, the variation cycle of HO2S-2 output voltage (oxygen concentration) is slower than that of HO2S-1 output voltage because of the amount of oxygen in the exhaust gas which has been stored in the catalyst.

Reference:

Detecting Condition / Possible Cause:

DTC CONFIRMATION PROCEDURE

WARNING:
- When performing a road test, select a place where there is no traffic or possibility of a traffic accident and be very careful during testing to avoid occurrence of an accident.
- Road test should be carried out with 2 persons, a driver and a tester, on a level road.

1. Turn ignition switch OFF.
Clear DTC with ignition switch ON, check vehicle and environmental condition for:
- Indication of fuel level meter in combination meter: 1/4 or more (For 1999 MY)
- Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
- Ambient temp.: -10 °C, 14 °F or higher
- Intake airtemp.: 70 °C, 158 °F or lower
- Engine coolant temp.: 70 - 110 °C, 158 - 230 °F.




2. Start engine and drive vehicle at 35 - 45 mph, 55 - 65 kph for 8 min. or longer.
While this driving, if "Catalyst Monitoring TEST COMPLETED" is displayed in "READINESS TESTS" mode and DTC is not displayed in "DTC" mode, confirmation test is completed.
If "TEST NOT COMPLTD" is still being displayed, continue test driving.
3. Decrease vehicle speed at 30 - 40 mph, 50 - 60 kph , and hold throttle valve at that opening position for 2 min. and confirm that short term fuel trim vary within -20% - +20% range.

Test Result Confirmation Table (Steps 1 - 2):

4. Stop vehicle (do not turn ignition switch OFF) and confirm test results according to following "Test Result Confirmation Flow Table".

Inspection (Steps 1 - 3):