Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Catalyst system efficiency below threshold

Toyota Corolla (E120): Catalyst system efficiency below threshold

Dtc p0420 catalyst system efficiency below threshold (bank 1)

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Inspection procedure
1 Inspect transmission wire(s2) Disconnect the transmission wire connector from the transaxle.  measure the resistance according to the value(s) in the table below. Standard: 2 Check harness and connector(transmission wire – ecm) Connect the transmission connec ...

Circuit description
Monitor description The ecm commands gearshift by turning the shift solenoid valves ”on/off”. When there is an open or short circuit in any shift solenoid valve circuit, the ecm detects the problem and the mil comes on. Illuminating the mil, the ecm performs the fail–safe and turns ...

Circuit description
The intake air temperature (iat) sensor, mounted on the mass air flow (maf) sensor, monitors the intake air temperature. The iat sensor has a thermistor that varies its resistance depending on the temperature of the intake air. When the air temperature is low, the resistance in the thermisto ...