FLA -398
FUEL SYSTEM
DTC P0420 CATALYST SYSTEM
EFFICIENCY BELOW THRESHOLD (BANK 1)
DTC P0430 CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD
(BANK 2)
GENERAL DESCRIPTION
EBD941FC
The ECM uses dual oxygen sensors to monitor the efficiency of the manifold catalytic converter (warm-up catalytic con-
verter). By monitoring the oxygen storage capacity of a catalyst, its efficiency can be indirectly calculated. The upstream
(front) HO2S is used to detect the amount of oxygen in the exhaust gas before it enters the catalytic converter. A low
voltage indicates high oxygen contents (lean air mixture). A high voltage indicates low oxygen contents (rich air mixture).
When the catalyst efficiency drops, no chemical reaction takes place. This means the concentration of oxygen will be the
same at the rear as it is at the front.
DTC DESCRIPTION
ED6771A8
If the oxygen storage time for Bank 1 is lower than threshold , the PCM determines that a fault exists and a DTC is stored
and MIL(Malfunction Indication Lamp) turns on.
DTC DETECTING CONDITION
E28777BF
Item
Detecting Condition
Possible cause
DTC Strategy
• Manipulates Airfuel and stores the times it takes for
the pre and post converter oxygen sensors to switch.
EnableConditions
• Engine Runtime ≥ 580 sec.
• Purge Concentration Learned
• 3 g/s ≤ Airflow ≤ 10 g/s
• Throttle closed ≤ 1.5%
• 70℃(158 F) ≤ Coolant Temp. ≤ 120℃(248 F)
• -7℃(19.4 F) ≤ Ambient Temp. ≤ 105℃(221 F)
• Barometer ≥ 72 kPa
• Max number of test attempts ≤ 12
• Closed Loop
• 250℃( 482 F) ≤ Catalyst Temp. ≤ 950℃(1742 F)
• Fuel learning completed
• Vehicle speed ≤ 3 kph(1.8 mph)
• Not airfuel ramping
• Max idle time( about 60 sec.) not exceeded
• No disabling faults present
• No instrumentation slews active
Threshold value
• Oxygen Storage Time < 3.25 sec.
DiagnosisTime
• 15 sec.
MIL On Condition
• 1 Driving cycle
• Catalyst Converter
MONITOR SCANTOOL DATA
E2E931EC
1.
Check DTC Status
1)
Connect scantool to Data Link Connector(DLC).
2)
IG "ON".