Catalyst Monitoring

DTC P0420 Catalyst system efficiency below threshold (Bank 1)
Possible Source(s):
- Catalyst failure
- Upstream O2 sensor failure
- Downstream O2 sensor failure
- O2 sensor heater failure
- Associated harness/connector failure

Action(s) to take
- See DTC P0137, P0138 & P0140 below.

DTC P0430 Catalyst system efficiency below threshold (Bank 2)
Possible Source(s):
- Catalyst failure
- Upstream O2 sensor failure
- Downstream O2 sensor failure
- O2 sensor heater failure
- Associated harness/connector failure

Action(s) to take
- See DTC P0157, P0158 & P0160 Oxygen Sensor

DTC P0420 Catalyst system efficiency below threshold (Bank 1)
Possible Source(s):
- Catalyst failure
- Upstream O2 sensor failure
- Downstream O2 sensor failure
- O2 sensor heater failure
- Associated harness/connector failure

Action(s) to take:
- See DTC P0137, P0138 & P0140 below.

DTC P0430 Catalyst system efficiency below threshold (Bank 2)
Possible Source(s):
- Catalyst failure
- Upstream O2 sensor failure
- Downstream O2 sensor failure
- O2 sensor heater failure
- Associated harness/connector failure

Action(s) to take:
- See DTC P0157, P0158 & P0160 Oxygen Sensor

DTC P0131 O2 sensor circuit low voltage (Bank 1 sensor 1)
Possible Source(s):
- O2 sensor failure
- Sensor ground fault
- Harness failure
- Connector pin(s) bent, loose or corroded

Action(s) to take:
- Go to Pinpoint Test A P0131

DTC P0132 O2 sensor circuit high voltage (Bank 1 sensor 1)
Possible Source(s):
- O2 sensor failure to B+
- Sensor ground fault
- Harness failure
- Connector pin(s) bent or tracking between connections.
- O2 sensor failure

Action(s) to take:
- Go to Pinpoint Test A P0131

DTC P0133 O2 sensor circuit slow response (Bank 1 sensor 1)
Possible Source(s):
- O2 sensor heater failure / out of spec
- Sensor ground fault
- Harness failure
- Connector pin(s) bent or tracking between connections.
- Low exhaust temperature
- O2 sensor failure

Action(s) to take:
- Go to Pinpoint Test B P0133

DTC P0135 O2 sensor heater circuit malfunction (Bank 1 sensor 1)
Possible Source(s):
- O2 sensor failure
- Harness failure
- Connector pin(s) bent or tracking between connections.
- ECM failure

Action(s) to take:
- Go to Pinpoint Test A P0131

DTC P0137 O2 sensor circuit low voltage (Bank 1 sensor 2)
Possible Source(s):
- O2 sensor failure
- Sensor ground fault
- Harness failure
- Connector pin(s) bent, loose or corroded

Action(s) to take:
- Go to Pinpoint Test C P0137

DTC P0138 O2 sensor circuit high voltage (Bank 1 sensor 2)
Possible Source(s):
- O2 sensor failure to B+
- Sensor ground fault
- Harness failure
- Connector pin(s) bent or tracking between connections.
- ECM failure

Action(s) to take:
- Go to Pinpoint Test C P0137

DTC P0140 O2 sensor circuit no activity detected (Bank 1 sensor 2)
Possible Source(s):
- O2 sensor failure / out of spec
- Sensor ground fault
- Harness failure
- Connector pin(s) bent or tracking between connections.
- Low exhaust temperature

Action(s) to take:
- Go to Pinpoint Test D P0140