P0140
DTC P0134, P0140, P0154, or P0160
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructionsprovides an overview of each diagnostic category.
DTC Descriptors
DTC P0134
- HO2S Circuit Insufficient Activity Bank 1 Sensor 1
DTC P0140
- HO2S Circuit Insufficient Activity Bank 1 Sensor 2
DTC P0154
- HO2S Circuit Insufficient Activity Bank 2 Sensor 1
DTC P0160
- HO2S Circuit Insufficient Activity Bank 2 Sensor 2
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,275 mV. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.
The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the control module to calculate the air-to-fuel ratio sooner.
Conditions for Running the DTC
* DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0207, P0208, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.
* The ignition 1 voltage is between 10-18 volts.
* The engine run time is greater than 300 seconds.
* The fuel system is in Closed Loop.
* DTC P0134 runs continuously when the above conditions are met.
Conditions for Setting the DTC
P0134 or P0154
* The ECM detects that the HO2S 1 voltage is between 350-550 mV for 100 seconds.
* The DTCs set within 100 seconds when the above conditions are met.
P0140 or P0160
* The ECM detects that the HO2S 2 voltage is between 410-490 mV.
* The throttle position has changed greater than 5 percent at least 6 times during the test.
* The DTCs set within 100 seconds when the above conditions are met.
Action Taken When the DTC Sets
DTCs P0134, P0140, P0154, and P0160 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0134, P0140, P0154, and P0160 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Connector End Views By Name
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
* Heated Oxygen Sensor Wiring Repairs Heated Oxygen Sensor Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Programming and Relearningfor scan tool information
Circuit/System Verification
1. Ignition OFF, open the hood to disable the Auto-Stop function. Refer to Hybrid Modes of Operation Description Hybrid Modes of Operation.
2. Ignition ON, verify the scan tool hood position parameter displays Open.
• If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F.
3. Ignition ON, observe the DTC information with a scan tool. Verify no HO2S heater DTCs are set.
• If a HO2S heater DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
4. Engine idling at operating temperature, observe the appropriate HO2S parameter with a scan tool. Verify the following:
- The HO2S 1 value should vary from below 200 mV to above 800 mV and respond to fueling changes.
- The HO2S 2 value should change greater than 200 mV when the throttle is quickly cycled 3 times from closed to wide open and back to closed after running the engine at 1,500 RPM for 30 seconds.
5. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Note: All modules must be powered down or misdiagnosis may result.
1. Ignition OFF, disconnect the scan tool and wait 60 seconds to ensure all modules are powered down.
2. Ignition OFF, disconnect the harness connector at the appropriate HO2S.
3. Ignition OFF, test for less than 5 ohm between the low reference circuit terminal A and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
4. Ignition ON, verify the appropriate scan tool HO2S parameter is approximately 450 mV.
• If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
• If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
5. Ignition ON, install a 3 A fused jumper wire between the signal circuit terminal B and ground. Verify the appropriate scan tool HO2S parameter is less than 60 mV.
• If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
6. If all circuits test normal, replace the appropriate HO2S.
Repair Instructions
Caution: Refer to Heated Oxygen Sensor Resistance Learn Reset Caution Heated Oxygen Sensor Resistance Learn Reset Caution.
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Heated Oxygen Sensor Replacement - Bank 1 Sensor 1
* Heated Oxygen Sensor Replacement - Bank 1 Sensor 2
* Heated Oxygen Sensor Replacement - Bank 2 Sensor 1
* Heated Oxygen Sensor Replacement - Bank 2 Sensor 2
* Control Module References Programming and Relearningfor ECM replacement, setup, and programming