Catalyst System Efficiency - Lotus Evora Service Notes

Lotus Service Notes

Catalyst System Efficiency

P0420 Catalyst System Efficiency Below Threshold (Bank 1)
P0430 Catalyst System Efficiency Below Threshold (Bank 2)
Description
The ECU compares the waveform of the oxygen sensors located before and after the catalyst to determine
whether or not the catalyst has deteriorated. If the catalyst is functioning normally the front oxygen sensor will
be switching between rich and lean whilst the rear oxygen sensor should also be switching between rich and
lean but more slowly. When both the oxygen sensor waveforms change at a similar rate, it indicates that the
catalyst performance has deteriorated. The ECU counts the number of pre and post catalyst oxygen sensor
switches and divides one by the other to determine a ratio. If this ratio is too high a fault will be indicated.
Sensor connections
Pre catalyst oxygen sensor
Sensor Connector Description
1 Bank 1 Signal
2 Bank 1 Ground
3 Bank 1 Heater Supply
4 Bank 1 Battery Voltage
1 Bank 2 Signal
2 Bank 2 Ground
3 Bank 2 Heater Supply
4 Bank 2 Battery Voltage
Post catalyst oxygen sensor
Sensor Connector Description
1 Bank 1 Signal
2 Bank 1 Ground
3 Bank 1 Heater Supply
4 Bank 1 Battery Voltage
1 Bank 2 Signal
2 Bank 2 Ground
3 Bank 2 Heater Supply
4 Bank 2 Battery Voltage
Monitor:
• Continuous
Enable Criteria:
• Closed loop fuel control enabled
• Coolant temperature > 60 °C (140 °F)
• Baro > 756 mbar
• Vehicle speed < 130 km/h (81 mph)
• MAF < 48 g/sec & MAF > 2 g/sec
• Air inlet temp > -10°C (14°F)
• Accumulated Mass Air > 2000-4080 grams depending on coolant temperature
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ECU Pin ECU Connector
G3 48 Way (Centre)
J2 48 Way (Centre)
H3 48 Way (Centre)
- -
G4 48 Way (Centre)
J2 48 Way (Centre)
H4 48 Way (Centre)
- -
ECU Pin ECU Connector
H1 48 Way (Centre)
K4 48 Way (Centre)
K1 48 Way (Centre)
- -
H2 48 Way (Centre)
K4 48 Way (Centre)
K2 48 Way (Centre)
- -
2009/02
Section EMR