P0037
DTC P0037: HO2S Heater Control Circuit Low Voltage Sensor 2Wiring Diagram:
Circuit Description
The DTC P0037 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
- Ignition ON with the engine running.
- Ignition voltage is between 11 and 16 V.
- A history DTC is stored.
- Enable time delay is greater than 0.5 second.
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 after four consecutive ignition cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 consecutive warm up cycles without a fault.
- The 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 P0037 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 1-12:
Troubleshooting