P0038

DTC P0038 Downstream Heated Oxygen Sensor Bank 1 Heater High Voltage

Wiring Diagram:

Circuit Description

The DTC P0038 monitors the HO2S heater circuit current. The heater is powered through the ignition switch and is grounded through the ECM heater control. The ECM commands the heater ON by grounding the heater control circuit. The HO2S sensor must be at operating temperature in order to accurately measure the oxygen content of the exhaust gas. The heater allows the HO2S to reach operating temperature quickly.

Conditions for Setting the DTC

- Heater power is between 2% and 98%.
- Short to battery condition exists.

Action Taken When the DTC Sets

- The Malfunction Indicator Lamp (MIL) will illuminate.
- The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC

- The MIL will turn off at the end of three (3) consecutive validation cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 warm up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

An intermittent malfunction may be caused by a problem in the HO2S electrical circuit. Inspect the wiring harness and the components for an intermittent condition. Refer to Intermittents. Intermittents If a DTC P0038 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

Step 1 - 8:

DTC P0038 - Downstream Heated Oxygen Sensor Bank 1 Heater High Voltage