Toyota Tacoma manuals

Toyota Corolla Repair Manual: Catalyst system efficiency below threshold

Toyota Corolla Repair Manual / Diagnostics / Sfi system / Catalyst system efficiency below threshold

Dtc p0420 catalyst system efficiency below threshold (bank 1)

Inspection procedure
Hint: read freeze frame data using the hand-held tester or the obd ii scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is usefu ...

Circuit description
The ecm compares the two waveforms of the heated oxygen sensors located before and after the catalyst to determine whether or not the catalyst performance has deteriorated. Airfuel ratio feedba ...

Other materials:

Precaution
1. Precaution of headlight bulb replacement  if even a thin film of oil is left on the surface of the halogen lamp, its service life will be shortened because the lamp will be burn at a higher temperature.  handle any halogen lamp with great care. Dropping, hitting or damagin ...

Dtc check/clear
1. Dtc check (normal mode) Notice: handheld tester only: when the diagnostic system is switched from the normal mode to the check mode, all the dtcs and freeze frame data recorded in the normal mode will be erased. So before switching modes, always check the dtcs and freeze frame data, and n ...

Inspection procedure
Hint: if different dtcs related to different systems that have terminal e2 as the ground terminal are output simultaneously, terminal e2 may be open. If dtc p0441 (purge flow), p0446 (vsv for ccv), p0451, p0452 or p0453 (evaporative pressure sensor) is output with dtc p0442 or p0456, ...

2011-2021 Copyright www.tcorolla.net