P0420
Read the instructions below then
start the fault diagnostic procedure.
Symptom: CHECK ENGINE.
Three Way Catalytic Converter. Malfunction.
Fault symptoms
On-Board Diagnostics
Type of diagnosis:
|
-
|
Once per driving cycle. Interrupted when fault criteria fulfilled or OK reported. Restarts next driving cycle.
|
Enable criteria:
|
-
|
General conditions for this trouble code: Atmospheric pressure must exceed 72 kPa and the engine coolant and intake air temperatures must exceed -7°C.
|
|
-
|
Ignition of front catalytic converter: Engine running. Mass air flow has exceeded 5 g/s (aut 7 g/s) during an accumulative time of 120 s. The mass air flow has exceeded 20 g/s during an accumulative time of 18 s. No engine braking with fuel shut-off for longer than 10 s. No idling for longer than 40 s.
Evaluation of catalytic converter: More than 200 sec. since start. Coolant temperature above 70°C. Speed 40-115 km/h. Accelerator pedal depressed. Engine speed 1270-2540 rpm (aut 1200-2100). Engine load 100-500 mg/c. Voltage transitions in oxygen sensor 2 are corrected with regard to load and engine speed and are accumulated under approved voltage periods for oxygen sensor 1*). When the voltage transitions have been corrected and accumulated for 20 sec their mean value is calculated.
*) Accepted periods have 30-80 % pulse ratio (+trigger).
|
Fault criteria:
|
-
|
Mean value of voltage transitions exceeding a calibrated value.
|
Dependents:
|
-
|
P0100, P0102, P0103, P0116, P0117, P0118, P0131, P0132, P0134, P0138, P0140, P0336, P0337, P0501, P0502, All throttle faults.
|
System reaction to a fault:
OK report:
|
-
|
Diagnosis performed once and fault criteria not fulfilled.
|
Fault handling:
(See section
Fault handling III, other emission-related components and functions
for more information.)
Diagnostic help
The capacity of the catalyst can be reduced temporarily or permanently for the following reasons:
|
•
|
Lead or sulphur in the fuel.
|
Functions in the diagnostic tool related to the fault:
|
•
|
Diagnostic status for the diagnosis.
|
See also description of read values in
Menu "Read Values"
for more information.
