Oxygen Sensor: Testing and Inspection

CIRCUIT DIAGRAM











HARNESS INSPECTION PROCEDURE

SENSOR INSPECTION

NOTE:
(1) Before checking, warm up the engine until the engine coolant temperature reaches 80 to 95°C (176 to 205°F).
(2) Use an accurate digital voltmeter.

1. Replace the oxygen sensor if there is a malfunction.

Tightening torque
Heated oxygen sensor: 50 - 60 Nm
(500 - 600 kg.cm, 37 - 44 lb.ft)

DTC P0130, P0131, P0132, P0135, P0137, P0138, P0141 - Heated Oxygen Sensor:

DTC P0133 - Heated Oxygen Sensor:

TROUBLESHOOTING PROCEDURES

DTC P0134, P0136 - Heated Oxygen Sensor:

HINT: Use the above chart when the lean/rich period is above 2.6 seconds in the condition that fully warm-up engine is 2,000-3,000 r.p.m and engine is above middle load.

TROUBLESHOOTING HINTS
1. If the heated oxygen sensor is defective abnormally, high emissions may occur.
2. If the heated oxygen sensor check has been normal, but the sensor output voltage is out of specification, check the following items related to the air fuel ratio control system.
- Faulty injector.
- Air leaks in the intake manifold.
- Faulty mass air flow sensor, EVAP valve and engine coolant temperature sensor.
- Wiring connection problem.
3. When O2 sensor output voltage is maintained as following for above 50 sec.
- Upstream : 0.4V-0.6V
- Downstream: 0.4V-0.5V





USING VOLTMETER

NOTE:
If you release the accelerator pedal suddenly with the engine running about 4000 rpm, the fuel supply will be stopped for a while. When you suddenly press the accelerator pedal, the voltage will reach 'B' range. Then, when you let the engine idle again, the voltage fluctuates between 'A' and 'B' range. In this case, the O2 sensor can be determined as good.

DTC P1123, P1124, P1127, P1128 - Air/Fuel Control:

AIR-FUEL CONTROL TROUBLESHOOTING PROCEDURE
HINT:
- Air/Fuel ratio stays rich or lean longer than specified period because of system malfunction.