P0132
DTC P0131, P0132, P0134, P0137, P0138, P0140, or P2A00
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 Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P0131
- HO2S Circuit Low Voltage Sensor 1
DTC P0132
- HO2S Circuit High Voltage Sensor 1
DTC P0134
- HO2S Circuit Insufficient Activity Sensor 1
DTC P0137
- HO2S Circuit Low Voltage Sensor 2
DTC P0138
- HO2S Circuit High Voltage Sensor 2
DTC P0140
- HO2S Circuit Insufficient Activity Sensor 2
DTC P2A00
- HO2S Performance Sensor 1
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 0-1,000 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
P0131 or P0137
* 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 voltage is between 10-32 V.
* The fuel system is operating in Closed Loop.
* Device controls are not active.
* The fuel level is greater than 10 percent.
* The throttle position (TP) is between 3-70 percent.
* Ethanol content is less than 87 percent.
* Decel fuel cut-off is not active.
* The DTCs run continuously when the above conditions are met for 5 s.
P0132 or P0138
* 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 voltage is between 10-32 V.
* The fuel system is operating in Closed Loop.
* Ethanol content is less than 87 percent.
* The fuel level is greater than 10 percent.
* The engine run time is greater than 20 s.
* The DTCs run continuously when the above conditions are met for 5 s.
P0134 or P0140
* 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 voltage is between 10-32 V.
* The engine run time is greater than 150 s.
* The fuel system is in Closed Loop.
* Ethanol content is less than 87 percent.
* The DTCs run continuously when the above conditions are met.
P2A00
* DTCs P0068, P0106, P0107, P0108, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0131, P0132, P0151, P0152, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P1516, P2101, P2119, P2135, P2176 are not set.
* The Ignition voltage is between 10-32 V.
* The engine run time is greater than 100 s.
* The engine speed is between 1,000-3,400 RPM.
* The engine air flow is between 4-30 g/s.
* The engine coolant temperature (ECT) is warmer than 65°C (149°F).
* Decel fuel cut-off is not active.
* DTC P2A00 runs continuously when the above conditions are met for 5 s.
Conditions for Setting the DTC
P0131 or P0137
The engine control module detects that the heated oxygen sensor voltage is less than 50 mV and the circuit is shorted to ground for greater than 50 s.
P0132 or P0138
The engine control module detects that the heated oxygen sensor voltage is greater than 1,050 mV and the circuit is shorted to voltage for greater than 13 s.
P0134 or P0140
The engine control module detects that the heated oxygen sensor voltage is greater than 1.7 V and is an open circuit for greater than 50 s.
P2A00
The ECM detects that the Loop Status parameter is open for greater than 50 s.
Action Taken When the DTC Sets
DTCs P0131, P0132, P0134, P0137, P0138, P0140 and P2A00 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0131, P0132, P0134, P0137, P0138, P0140 and P2A00 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Sunshade - Left
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
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify no HO2S heater DTCs are set.
• If a DTC is set.
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
• If a DTC is not set.
3. Engine running.
4. Verify the scan tool HO2S Sensor 1 or 2 parameters are between 50-1,050 mV.
• If not between 50-1,050 mV.
Refer to Circuit/System Testing.
• If between 50-1,050 mV.
5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
6. Verify the DTC does not set.
• If the DTC sets.
Refer to Circuit/System Testing.
• If the DTC does not set.
7. All OK.
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the appropriate B52 Heated Oxygen Sensor harness connector. It may take up to 2 minutes for all vehicle systems to power down. Ignition ON.
2. Test for 1.7-3.0 V between the high signal circuit terminal 4 and ground.
• If less than 1.7 V
1. . Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the high signal circuit terminal 4 and ground.
• If less than infinite resistance repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the high signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.
• If greater than 3.0 V
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than 1 V between the high signal circuit terminal 4 and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 Engine Control Module.
• If between 1.7-3.0 V
3. Verify the scan tool HO2S sensor 1 or 2 parameter is between 1.7-2.1 V.
• If less than 1.7 V
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the low signal circuit terminal 3 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K20 Engine Control Module.
• If between 1.7-2.1 V
4. Connect a 3 A fused jumper wire between the high signal circuit terminal 4 and the low signal circuit terminal 3.
Note: The low signal circuit is tied to a pull-up circuit within the engine control module. A voltage of 0.0-1.10 V on the low signal circuit is normal.
5. Verify the scan tool HO2S sensor 1 or 2 parameter displays 0.0 V.
• If greater than 0.0 V
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than 2 ohms in the low signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms
3. Test for less than 1 V between the low signal circuit terminal 3 and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 Engine Control Module.
• If 0.0 V
6. Verify none of the conditions listed below exist:
* Water intrusion in the B52 Heated Oxygen Sensor harness connector
* Low or high fuel system pressure-Refer to Fuel System Diagnosis Fuel System Diagnosis.
* Fuel that is contaminated-Refer to Alcohol/Contaminants-in-Fuel Diagnosis Testing and Inspection.
* Fuel saturation of the evaporative emission (EVAP) canister
* Exhaust leaks
* Engine vacuum leaks
• If any of the conditions exist
Repair as necessary.
• If none of the conditions exist
Test or replace the B52 Heated Oxygen Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Heated Oxygen Sensor Replacement - Sensor 1 (LCV) Heated Oxygen Sensor Replacement - Sensor 1Heated Oxygen Sensor Replacement - Sensor 1 (LTG) Heated Oxygen Sensor Replacement - Sensor 1
* Heated Oxygen Sensor Replacement - Sensor 2 (LCV) Heated Oxygen Sensor Replacement - Sensor 2Heated Oxygen Sensor Replacement - Sensor 2 (LTG) Heated Oxygen Sensor Replacement - Sensor 2
* Perform the scan tool Heated Oxygen Sensor Resistance Learn Reset after replacing an HO2S.
* Control Module References Control Module References for ECM replacement, programming and setup