1998 Toyota Camry XLE Sedan V6-2995cc 3.0L DOHC MFI
DTC P0420 Catalyst System Efficiency Below Threshold (Only For California Spec.)
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CIRCUIT DESCRIPTION
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 flatteringly between rich and lean, it indicates that
catalyst performance has deteriorated.
DETECTING
CONDITIONS
CONFIRMATION ENGINE RACING PATTERN
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(a) |
Connect the OBD II scan tool or TOYOTA hand-held tester to the DLC3. |
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(b) |
Start engine and warm it up with all accessories switched OFF until water temp. is stable. |
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(c) |
Race the engine at 2,500 ~ 3,000 rpm for about 3 min. |
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(d) |
When racing the engine at 3,000 rpm for 2 sec. and 2,000 rpm for 2 sec. alternately, check the waveform of the heated oxygen sensor (bank 1 sensor 2). |
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Step 1 |
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Step 2 |
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Step 3 |
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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 warmed up or not, the air-fuel ratio lean or rich, etc. at the time of the malfunction.
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For more Information take a lockthis Article about Catalytic Converter (Russian)
