Description of DTC code P0038

The readings provided by the Oxygen Sensors (O2) are used by the Power Train Control Module (PCM) to determine the oxygen content in the exhaust system. Each of these sensors has a heating element whose objective is to reduce the time it takes to have a closed cycle.

The PCM is the one that controls the ignition time of said heater, in addition it constantly monitors the circuits of the heater in search of voltages or in some cases amperages that are outside the expected level.

If the Powertrain Control Module (PCM) detects a high voltage condition in excess, the DTC code P0038 OBDII is set in the circuit of the heating element.

Symptoms of fault code P0038

  • Illuminated MIL light.
  • A difficult start.
  • Black smoke comes out of the exhaust.
  • Increase fuel consumption.
  • Power loss.

Causes of OBD2 P0038

The reasons why the diagnostic code P0038 OBD2 is stored are:

  • Cables related to the Oxygen Sensors could have very little distance from the hot exhaust components. As a result, the cables burn.
  • Short circuit due to defective cables.
  • Connections may be incorrect, perhaps due to impact or corrosion damage.
  • A bad ground connection.
  • Burned fuses in the heater control circuit.
  • Defective Oxygen Sensor.

Possible solutions of the DTC code P0038

To solve the problems of the P0038 OBDII fault code you must do the following:

  • If there are codes referring to air / fuel measurement problems, you must correct these codes.
  • Make sure there are no escape leaks before carrying out the diagnosis of code P0038. In case they are present, you should repair them, since these leaks contaminate the atmospheric air used by the Oxygen Sensor (O2), resulting in inaccurate readings.
  • Thoroughly inspect the cables and connectors related to this fault code, also check the fuses. Repair or replace any defective component. Delete the code and see if it returns.
  • Check continuity and resistance on all cables in the circuit. Take into account that the input voltage must be equal to the batter's voltage. Therefore check that the battery is fully charged, also before doing these tests disconnect the PCM sensor to avoid damage to the controller.
  • Replace the Oxygen Sensor.

Codes related to P0038

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