California Only

CIRCUIT DESCRIPTION
The ECM observes the wave form 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 wave form of the heated oxygen sensor located behind the catalyst switches back and forth between rich and lean much more slowly. When the wave form of the heated oxygen sensor located behind the catalyst alternates flatteringly between rich and lean, it indicates that catalyst performance has deteriorated.




DETECTING CONDITIONS




CONFIRMATION ENGINE RACING PATTERN
1. Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC 3.
2. Start the engine and warm it up with all the accessories switched OFF until the water temperature is stable.
3. Race the engine at 2,500 - 3,000 rpm for about 3 mm.
4. When racing the engine at 3,000 rpm for 2 sec. and 2,000 rpm for 2 sec. alternately, check the wave form of the heated oxygen sensor (bank 1 sensor 2).

Step 1:

Step 2:

Step 3:

Step 4:

INSPECTION PROCEDURE

HINT: Read freeze frame data using TOYOTA hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when the 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.