P0135
P0135-O2 SENSOR 1/1 HEATER PERFORMANCE
For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams. Electrical Diagrams
Theory of Operation
The engine aftertreatment system monitors the O2 content in the diesel engine exhaust. The Engine Control Module (ECM) monitors the exhaust gases for oxygen content and varies the rich/lean fuel mixture of the intake air fuel mixture to adjust the system. This diagnostic monitors the status message broadcast by the Smart O2 sensor module for the upstream O2 sensor circuit. The ECM will set the fault if it receives a FMI (Failure Mode Indicator) message from the Smart O2 Module. The ECM will illuminate the MIL lamp immediately when the diagnostic runs and fails. The ECM will turn off the MIL lamp diagnostic runs and passes in four consecutive drive cycles.
- When Monitored:
This diagnostic runs when the engine is running.
- Set Condition:
The Engine Control Module (ECM) will set the fault if it receives a FMI (Failure Mode Indicator) message from the Smart O2 Module.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
NOTE: Before replacing O2 Sensor or O2 Sensor Module, check aftertreatment wiring harness for spread terminals. For wiring harness checking procedure, DO NOT back probe, use Miller Tool Kit 8197A (6801 Tool ).
1. (K99) O2 1/1 HEATER SUPPLY CIRCUIT OPEN/HIGH RESISTANCE
1. Disconnect the Oxygen Sensor harness connector.
2. Disconnect the Smart O2 Sensor Module harness connector.
NOTE: Check connectors - Clean/repair as necessary, inspect for signs of Water intrusion in the connector.
3. Measure the resistance of the (K99) O2 Sensor 1/1 Heater Supply circuit between the O2 Sensor 1/1 harness connector and the Smart O2 Sensor Module harness connector.
Is the resistance below 10.0 Ohms?
Yes
- Go To 2
No
- Repair the open or high resistance in the (K99) O2 Sensor 1/1 Heater Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
2. (K79) O2 1/1 HEATER RETURN CIRCUIT OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K79) O2 Sensor 1/1 Heater Return circuit between the O2 Sensor 1/1 harness connector and the Smart O2 Sensor Module harness connector.
Is the resistance below 10.0 Ohms?
Yes
- Go To 3
No
- Repair the open or high resistance in the (K79) O2 Sensor 1/1 Heater Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
3. OXYGEN SENSOR
1. Measure resistance of the O2 Sensor Heater between the (K99) O2 Sensor 1/1 Heater Supply and (K79) O2 Sensor 1/1 Heater Return circuit at the O2 Sensor.
Is the resistance 3.2 ± 0.8 Ohms at ambient temperature?
Yes
- Replace Smart O2 Sensor Module.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Replace the O2 Sensor.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.