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 Descriptor
DTC P0030: HO2S Heater Control Circuit Bank 1 Sensor 1DTC P0036: HO2S Heater Control Circuit Bank 1 Sensor 2
DTC P0135: HO2S Heater Performance Bank 1 Sensor 1
DTC P0141: HO2S Heater Performance Bank 1 Sensor 2
Diagnostic Fault Information
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
HO2S Heater Voltage Supply | Opens fuse | P0030, P0036, P0135, P0141 | P0030, P0036, P0135, P0141 | -- | P0135, P0141 |
HO2S Heater Low Control | P0030, P0036 | P0030, P0036, P0135, P0141 | P0030, P0036, P0135, P0141 | P0030, P0036, P0135, P0141 | P0135, P0141 |
Typical Scan Tool Data
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
HO2S Heater Low Control | 1-2 A | 0 A | 0 A | 0 A |
HO2S Heater Voltage Supply | 1-2 A | 0 A | 0 A | 1-2 A |
Circuit/System Description
Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensor to reach operating temperature. Voltage is provided to the heater by the ignition 1 voltage circuit through a fuse. With the engine running, ground is provided to the heater by the HO2S heater low control circuit, through a low side driver within the powertrain control module (PCM). The PCM commands the heater ON or OFF to maintain a specific HO2S operating temperature range.
P0030 or P0036
The PCM monitors the voltage on the HO2S heater low control circuit for heater fault diagnosis. If the PCM detects that the HO2S heater low control circuit voltage is not within a specified range, DTC P0030 sets for HO2S 1, or DTC P0036 sets for HO2S 2.
P0135 or P0141
The PCM determines the temperature by measuring the current flow through the heater and calculating the resistance. Based on the resistance, the PCM can predict the sensor temperature. The HO2S 1 uses pulse width modulation (PWM) to control the heater operation. The HO2S 2 simply uses ON/OFF commands to control the heater operation. For diagnosis, the PCM monitors the heater current with the engine running. The PCM also calculates the heater resistance on a cold start. Both diagnostics will only run once per ignition cycle.
Conditions for Running the DTC
P0030 or P0036
| • | The Ignition 1 Signal parameter is between 11-18 volts. |
| • | The engine speed is more than 425 RPM. |
| • | DTC P0030 and P0036 runs continuously when the above conditions are met for 1 second. |
P0135 or P0141 Heater Current Test
| • | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0420, P0440, P0442, P0443, P0446, P0449, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1441, P1680, P1681, P2101, P2122, P2123, P2127, P2128 are not set. |
| • | The ECT Sensor parameter is more than 70°C (158°F). |
| • | The Ignition 1 Signal parameter is between 11-18 volts. |
| • | The MAF Sensor parameter is between 15-30 g/s. |
| • | The Engine Run Time parameter is more than 230 seconds. |
| • | The Engine Speed parameter is between 1,000-2,500 RPM. |
| • | The traction control is not active. |
| • | The O2 heater overtemp control is not active. |
| • | The heater current test runs twice per drive cycle when the above conditions are met for 1 second. |
P0135 or P0141 Heater Resistance Test
| • | DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0222, P0420, P0440, P0442, P0443, P0446, P0449, P1106, P1107, P1111, P1112, P1114, P1115, P1120, P1220, P1221, P1271, P1275, P1280, P1441, P1680, P1681, P2101, P2122, P2123, P2127, P2128 are not set. |
| • | The ignition is OFF for more than 10 hours. |
| • | The ECT Sensor parameter is between -30°C to +45°C (-22°F to +113°F) at engine start-up. |
| • | The difference between the ECT and the IAT Sensor parameter is less than 140°C (252°F) at engine start-up. |
| • | The engine is running. |
| • | The heater resistance test runs once per cold start when the above conditions are met for 1 second. |
Conditions for Setting the DTC
P0030 or P0036
| • | The PCM detects that the actual state of the affected HO2S heater low control circuit does not equal the expected state. |
| • | DTCs P0030 and P0036 set within 3 seconds when the above condition is met. |
P0135 Heater Current Test
| • | The PCM detects that the HO2S 1 heater current parameter is more than 2.7 amps or less than 0.73 amp. |
| • | DTC P0135 sets within 30 seconds during the heater current test when the above condition is met. |
P0135 Heater Resistance Test
| • | The PCM detects that the HO2S 1 heater calculated resistance is not within an expected range at engine start-up. |
| • | DTC P0135 sets within 30 seconds during the heater resistance test when the above condition is met. |
P0141 Heater Current Test
| • | The PCM detects that the HO2S 2 heater current parameter is more than 2.3 amps or less than 0.6 amp. |
| • | DTC P0141 sets within 30 seconds during the heater current test when the above condition is met. |
P0141 Heater Resistance Test
| • | The PCM detects that the HO2S 2 heater calculated resistance is not within an expected range at engine start-up. |
| • | DTC P0141 sets within 5 seconds during the heater resistance test when the above condition is met. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
- Allow the engine to reach operating temperature. With the engine running, observe the HO2S Heater parameter with a scan tool. The value should vary from below 2 A to above 1 A.
- With the engine running at operating temperature, observe the HO2S Heater parameter with a scan tool and manipulate the related wiring and connectors.
| ⇒ | If manipulation does affect the parameter, repair the harness or connector. |
Circuit/System Testing
- With the ignition ON, the engine OFF, and the sensor disconnected, connect a test lamp between the HO2S heater supply voltage circuit terminal D and ground. The lamp should illuminate.
- With the ignition OFF, connect a test lamp between the HO2S low control circuit terminal E and battery voltage. The lamp should not illuminate.
- With the engine RUNNING, leave the test lamp connected from the previous step. The lamp should flash or be ON steady.
- Test for less than 5 ohms resistance in the HO2S heater voltage supply circuit and the low control circuit.
| ⇒ | If the lamp illuminates then test the low control circuit for a short to ground. If the circuit tests normal, replace the PCM. |
| ⇒ | If the test lamp is not ON steady or flashing, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PCM. |
| ⇒ | If the control module and all circuits test normal, replace the HO2S. |
Repair Instructions
Notice: Refer to Heated Oxygen Sensor Resistance Learn Reset Notice in the Preface section.
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for PCM replacement, setup, and programming |
