P0032
DTC P0032
DTC DESCRIPTOR
DTC P0031
HO2S Heater Control Circuit Low Voltage Sensor 1
DTC P0032
HO2S Heater Control Circuit High Voltage Sensor 1
DTC P0037
HO2S Heater Control Circuit Low Voltage Sensor 2
DTC P0038
HO2S Heater Control Circuit High Voltage Sensor 2
DIAGNOSTIC FAULT INFORMATION
IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
TYPICAL SCAN TOOL DATA
HO2S Heater:
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 control module. The control module commands the heater ON or OFF to maintain a specific HO2S operating temperature range.
The control module monitors the voltage on the HO2S heater low control circuit for heater fault diagnosis. If the control module detects that the HO2S heater low control circuit voltage is not within a specified range, DTC P0031 or P0032 sets for HO2S 1, or DTC P0037 or P0038 sets for HO2S 2.
CONDITIONS FOR RUNNING THE DTC
- The Ignition 1 Signal parameter is between 11-18 volts.
- The engine coolant temperature is more than 69.5°C (157.1°F).
- The fuel level is more than 9.8 percent.
- The engine run time is more than 10 seconds.
- No intrusive catalyst monitor test is active.
- DTC P0031, P0032, P0037, and P0037 run continuously when the above conditions are met for 1 second.
CONDITIONS FOR SETTING THE DTC
- The control module detects that the affected HO2S heater low control circuit is not within a specified range.
- DTCs P0031, P0032, P0037, and P0037 set within 3 seconds when the above condition is met.
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.
CIRCUIT/SYSTEM TESTING
1. 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 then repair the harness or connector.
2. With the ignition ON, the engine OFF, and the sensor disconnected, connect a test lamp between the HO2S sensor heater supply voltage circuit and ground. The lamp should illuminate.
- If the lamp does not illuminate then test the voltage supply circuit for high resistance or for a short to ground.
3. With the ignition OFF, connect a test lamp between the HO2S sensor low control circuit and battery voltage. The lamp should not illuminate.
- If the lamp illuminates then test the low control circuit for a short to ground or a faulty control module.
4. With the 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, then test the control circuit for a short to voltage, high resistance, or a faulty control module.
5. Test for less than 5 ohms resistance in the HO2S sensor heater supply voltage circuit, the low control circuit, and the control module.
- If more than 5 ohms, then repair the circuit with high resistance or replace the control module.
6. If the control module and all circuits test normal, replace the HO2S sensor.
REPAIR INSTRUCTIONS
IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Heated Oxygen Sensor Replacement - Position 1
- Heated Oxygen Sensor Replacement - Position 2
- Control Module References for control module replacement, setup, and programming Verification Tests