Lotus Evora - O2 Sensor (Post Catalyst)

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Lotus Service Notes Section EMR
O2 Sensor (Post Catalyst)
P0137 O2 Sensor Circuit Low Voltage (Bank 1)
P0138 O2 Sensor Circuit High Voltage (Bank 1)
P0139 O2 Sensor Circuit Slow Response (Bank 1)
P0140 O2 Sensor Circuit No Activity Detected (Bank 1)
P0141 O2 Sensor Heater Circuit (Bank 1)
P0157 O2 Sensor Circuit Low Voltage (Bank 2)
P0158 O2 Sensor Circuit High Voltage (Bank 2)
P0159 O2 Sensor Circuit Slow Response (Bank 2)
P0160 O2 Sensor Circuit No Activity Detected (Bank 2)
P0161 O2 Sensor Heater Circuit (Bank 2)
Description
The oxygen sensors separately monitor the oxygen content in the exhaust gases of each bank of the engine.
Each sensor is electrically heated to improve response from start.
The sensor consists of a zirconia electrode between two platinum plates. When zirconia comes into contact with
oxygen, it becomes an electrical conductor. The exhaust gases passes through louvers in the sensor. One plate
is in contact with the outside air and the other plate is in contact with the exhaust gases. The platinum plate in
contact with the air is electrically negative due to the oxygen in the atmosphere and the plate in contact with
the exhaust gases is electrically positive. This will cause a difference in electrical potential to develop between
the two plates. Thus the voltage across the platinum plates ranges approximately from 100 millivolts to 900
millivolts, depending on the oxygen content of the exhaust gases. Thus when the air/fuel mixture is rich, the
oxygen sensor output will be high. If the air/fuel mixture is lean, the oxygen sensor output will be low. The post
catalyst oxygen sensor performance is a good indicator of catalyst efficiency.
Sensor connections
Sensor Connector Description ECU Pin ECU Connector
1 Bank 1 Signal H1 48 Way (Centre)
2 Bank 1 Ground K4 48 Way (Centre)
3 Bank 1 Heater K1 48 Way (Centre)
4 Bank 1 Battery Voltage - -
1 Bank 2 Signal H2 48 Way (Centre)
2 Bank 2 Ground K4 48 Way (Centre)
3 Bank 2 Heater K2 48 Way (Centre)
4 Bank 2 Battery Voltage - -
Sensor characteristics
Normal operating range is 0 – 1000mV
P0137, P0157
Monitor:
• Continuous
Enable Criteria:
• None
Disable Criteria:
• DFCO(DecelerationFuelCutOff)
• AEDE(AccelerationEnrichmentorDecelerationEnleanment)
• Misfire
Malfunction Criteria:
• Setwhenthesensoroperatesbelow15mVformorethan1.5secondsconsecutivelyforaspecifiednumber
of times.
2009/02