Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P0135: HO2S Heater Performance Bank 1 Sensor 1DTC P0141: HO2S Heater Performance Bank 1 Sensor 2
DTC P0155: HO2S Heater Performance Bank 2 Sensor 1
DTC P0161: HO2S Heater Performance Bank 2 Sensor 2
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Ignition 1 Voltage | P0135, P0141 | P0135, P0141 | -- | -- |
HO2S 1 Heater Control | P0135 | P0135 | P0135 | -- |
HO2S 2 Heater Control | P0141 | P0141 | P0141 | -- |
Circuit Description
The heated oxygen sensor (HO2S) heater reduces the time required for the oxygen sensor to reach operating temperature and maintains the operating temperature during extended idle periods. When the ignition is turned to the ON position, ignition voltage is supplied directly to the sensor heater. The engine control module (ECM) controls the heater operation by first modulating the control circuit to ground when the sensors are cold. This prevents the possibility of thermal shock to the sensor, from condensation build-up on the sensor, by controlling the sensor's rate of heating. After a predetermined amount of time, the ECM commands the heaters ON continuously. Once the sensor reaches operating temperature, the ECM may modulate the heater control circuit to ground to maintain a desired temperature.
Conditions for Running the DTC
P0135 or P0155
| • | DTCs P0101, P0102, P0103, P0107, P0108, P0121, P0122, P0123, P0131, P0132, P0133, P0151, P0152, P0153, P0221, P0222, or P0223 are not set. |
| • | The engine is running. |
| • | The ignition 1 voltage is between 10-16 volts. |
| • | The exhaust gas temperature at the HO2S is less than 600°C (1,112°F). |
| • | The engine run time is greater than 4 minutes. |
| • | The DTCs run once a drive cycle. The ECM will attempt to run this diagnostic until results are obtained. |
P0141 or P0161
| • | DTCs P0101, P0102, P0103, P0121, P0122, P0123, P0221, P0222, or P0223 are not set. |
| • | The engine is running. |
| • | The ignition 1 voltage is between 10-16 volts. |
| • | The exhaust gas temperature at the HO2S is less than 600°C (1,112°F). |
| • | The engine run time is greater than 2 minutes. |
| • | The DTCs run once a drive cycle. The ECM will attempt to run this diagnostic until results are obtained. |
Conditions for Setting the DTC
P0135 or P0155
The ECM detects the heater resistance to be less than 1,200 ohms.
P0141 or P0161
The ECM detects the heater resistance to be less than 700 ohms.
Action Taken When the DTC Sets
DTCs P0135, P0141, P0155, and P0161 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0135, P0141, P0155, and P0161 are Type B DTCs.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine at normal operating temperature, operate the engine above 1,200 RPM for 30 seconds and then allow the engine to idle. DTCs P0135, P0141, P0155, or P0161 should not set.
- 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.
Important: It may take up to 8 minutes for the DTC to set.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the appropriate HO2S.
- Ignition ON, test for battery voltage between the ignition voltage circuit terminal 2 and ground.
- Ignition OFF, connect a test lamp between the control circuit terminal 4 and 12 volts.
- Ignition ON, test for less than 0.3 volt between the control circuit terminal 4 at the test lamp probe and ground.
- If all circuits test normal, test or replace the HO2S.
| ⇒ | If less than B+, repair the ignition voltage circuit for a short to ground or an open/high resistance. |
| ⇒ | If test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
Component Testing
- Ignition OFF, disconnect the harness connector at the appropriate HO2S.
- Test for 3-35 ohms of reisistance between terminals 2 and 4.
| ⇒ | If not within the specified range, replace the HO2S. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module replacement, setup, and programming |
