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Toyota
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1989
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Van Base, Van Window, Standard
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Repair and Diagnosis
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Engine Performance
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Tests W/Codes - EFI
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Diagnostic Tests
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Code 21 - O2 Sensor/Heater Signal
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Probable Cause
Probable Cause
O2 Sensor Circuit
O2 Sensor
O2 Sensor Heater Circuit
O2 Sensor Heater
ECU
NOTE:
Diagnostic circuit chart not available from manufacturer.