For 1990-2009 cars

### 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 P0030: HO2S Heater Control Circuit Sensor 1
DTC P0036: HO2S Heater Control Circuit Sensor 2
DTC P0053: HO2S Heater Resistance Sensor 1
DTC P0054: HO2S Heater Resistance Sensor 2
DTC P0135: HO2S Heater Performance Sensor 1
DTC P0141: HO2S Heater Performance 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, P0053, P0054, P0135, P0141 | P0030, P0036, P0135, P0141 | -- | P0135, P0141
HO2S Heater Low Control | P0030, P0036 | P0030, P0036, P0053, P0054, P0135, P0141 | P0030, P0036, P0135, P0141 | P0030, P0036, P0135, P0141 | P0135, P0141

### Typical Scan Tool Data

#### HO2S Heater

Circuit | Normal Range | Short to Ground | Open | Short to Voltage
--- | --- | --- | --- | ---
HO2S Heater Low Control | 1-2A | 0A | 0A | 0A
HO2S Heater Voltage Supply | 1-2A | 0A | 0A | 1-2A

### 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 an ignition 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 engine control module (ECM). The ECM uses pulse width modulation (PWM) to control the HO2S heater operation to maintain a specific HO2S operating temperature range.

#### P0030 or P0036

The ECM monitors the voltage on the HO2S heater low control circuit for heater fault diagnosis.

#### P0053 or P0054

The ECM determines the temperature by measuring the current flow through the heater and calculating the resistance. Based on the resistance, the ECM can predict the sensor temperature. The HO2S uses pulse width modulation (PWM) to control the heater operation. The ECM calculates the heater resistance on a cold start. This diagnostic will only run once per ignition cycle.

### Conditions for Running the DTC

#### P0030 or P0036

• | The Ignition 1 Signal parameter is between 10-18 volts.

• | The engine speed is more than 400 RPM.

• | DTC P0030 and P0036 runs continuously when the above conditions are met for 1 second.

#### P0053 or P0054

• | DTCs P0112, P0113, P0117, P0118 are not set.

• | The engine is started.

• | The ignition is OFF for more than 10 hours.

• | The ECT Sensor parameter is between 0-40°C (32-104°F) at engine start-up.

• | The ECT Sensor parameter minus the IAT Sensor parameter is less than 8°C (14°F) at engine start-up.

• | DTCs P0053 and P0054 run once per drive cycle when the above conditions are met.

#### P0135 Heater Current Test

• | DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.

• | The ECT Sensor parameter is more than 70°C (158°F).

• | The Ignition 1 Signal parameter is between 10-18 volts.

• | The MAF Sensor parameter is between 5-25 g/s.

• | The Engine Run Time parameter is more than 60 seconds.

• | The Engine Speed parameter is between 500-3,000 RPM.

• | DTC P0135 runs the heater current test twice per drive cycle when the above conditions are met for 2 seconds.

#### P0141 Heater Current Test

• | DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0201, P0202, P0203, P0204, P0220, P0222, P0223, P0442, P0443, P0446, P0449, P0455, P0496, P1516, P2101, P2119, P2135, P2176 are not set.

• | The ECT Sensor parameter is more than 70°C (158°F).

• | The Ignition 1 Signal parameter is between 10-18 volts.

• | The MAF Sensor parameter is between 5-25 g/s.

• | The Engine Run Time parameter is more than 60 seconds.

• | The Engine Speed parameter is between 500-3,000 RPM.

• | DTC P0141 runs the heater current test twice per drive cycle when the above conditions are met for 2 seconds.

### Conditions for Setting the DTC

#### P0030 or P0036

• | The ECM detects that the affected HO2S heater low control circuit is not within a specified range.

• | DTCs P0030 and P0036 set within 3 seconds when the above condition is met.

#### P0053 or P0054

• | The ECM detects that the affected HO2S heater low control circuit is not within a specified range at engine start-up.

• | DTCs P0053 and P0054 set within one second when the above condition is met.

#### P0135 Heater Current Test

• | The ECM detects that the HO2S 1 Heater parameter is more than 2.5 amps or less than 0.25 amp.

• | DTC P0135 sets within 30 seconds during the heater current test when the above condition is met.

#### P0141 Heater Current Test

• | The ECM detects that the HO2S 2 Heater parameter is more than 2.5 amps or less than 0.25 amp.

• | DTC P0141 sets within 30 seconds during the heater current test when the above condition is met.

### Action Taken When the DTC Sets

DTC P0030, P0036, P0053, P0054, P0135, P0141 are Type B DTCs.

### Conditions for Clearing the MIL/DTC

DTC P0030, P0036, P0053, P0054, P0135, P0141 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Control Module Connector End Views

• | Engine Controls Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

• | Heated Oxygen Sensor Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Scan Tool Data List

### Circuit/System Verification

1. Allow the engine to reach operating temperature.
2. Engine running, verify the appropriate scan tool HO2S Heater parameter is varying between 0.5-2 amps.

### Circuit/System Testing

Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF, disconnect the harness connector at the appropriate HO2S.
2. Ignition ON, verify that a test lamp illuminates between the appropriate HO2S heater voltage supply circuit terminal D and ground.

⇒ | If the test lamp does not illuminate, test the HO2S heater voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the HO2S heater voltage supply circuit fuse is open, test all components connected to the fuse and replace as necessary.

3. Ignition ON, verify that a test lamp does not illuminate between the appropriate HO2S heater low control circuit terminal C and the HO2S heater voltage supply circuit terminal D.

⇒ | If the lamp illuminates, test the HO2S heater low control circuit for a short to ground. If the circuit tests normal, replace the ECM.

4. Engine running, leave the test lamp connected from the previous step. The lamp should flash or be ON steady.

⇒ | If the test lamp is not ON steady or flashing, test the HO2S heater low control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

Important:

• | The output driver should detect a short to voltage and turn OFF. If a resistance fault is present the driver will remain ON and the scan tool will display more than 0.0 amp. Less than 10 ohms of resistance may set a DTC.

• | Performing this test may set additional DTCs.

5. Ignition OFF, install a 30A fused jumper wire between the appropriate HO2S heater low control circuit terminal C and the HO2S heater voltage supply circuit terminal D.
6. Engine running, verify the appropriate scan tool HO2S Heater parameter is less than 0.1 amp.

⇒ | If more than the specified range, test the HO2S heater voltage supply and HO2S heater low control circuits for more than 1 ohm of resistance. If the circuits test normal, replace the ECM.

7. If the ECM and all circuits test normal, replace the appropriate 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.

• | Heated Oxygen Sensor 1 Replacement

• | Heated Oxygen Sensor 2 Replacement

• | Control Module References for replacement, setup, and programming