Troubleshooting

CIRCUIT DESCRIPTION

DTC Detection Condition:

The ECM observes the waveform of the heated oxygen sensor located behind the catalyst to determine whether the catalyst is performance has deteriorated. If the catalyst is functioning normally, the waveform of the heated oxygen sensor located behind the catalyst switches back and forth between rich and lean much more slowly. When the waveform of the heated oxygen sensor located behind the catalyst alternates flattering between rich and lean, it indicates that catalyst performance has deteriorated.

CONFIRMATION ENGINE RACING PATTERN

Confirmation Engine Racing Pattern:

a. Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC3.
b. Start the engine and warm it up with all the accessories switched OFF until the water temperature is stable.
c. Race the engine at 2,500 - 3,000 rpm for about 3 minutes.
d. When racing the engine at 3,000 rpm for 2 seconds and 2,000 rpm for 2 seconds alternately, check the waveform of the heated oxygen sensor (bank 1 sensor 2).

Steps 1 - 2:

Steps 3 - 4:

INSPECTION PROCEDURE

HINT: Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.