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)
Other materials:
Inspection procedure
1 Inspect stop lamp switch assy
Check that the stop light lights up when brake pedal is depressed and
turns off when the brake pedal
is released.
2 Inspect skid control ecu terminal voltage(stp terminal)
Disconnect skid control ecu connector.
measure voltage between termina ...
Evap monitor (vacuum pressure monitor) (continued)
Preconditions
The monitor will not run unless:
mil is off.
Fuel level is approximately 1/2 to 3/4.
Altitude is 7800 feet (2400 m) or less.*
Engine coolant temperature (ect) is between 40°f and 95°f (4.4 °C and 35
°C).
Intake air temperature (iat) is between 40°f and 95 ...
On–vehicle inspection
1. Check cooling fan operation with low temperature (below 83 c (181 f))
Turn the ignition switch on.
check that the cooling fan stops.
Hint:
if not, check the cooling fan relay and water temperature sensor, and check for
separated connector or severed
wire between the cooling fan ...