WOMS
P code powertrain Medium severity

P202A Reductant Tank Heater Control Circuit/Open

The OBD2 code P202A indicates a malfunction in the reductant tank heater control circuit, specifically that the circuit is open or not functioning properly, which can affect the operation of the vehicle's emissions...

Definition

The OBD2 code P202A indicates a malfunction in the reductant tank heater control circuit, specifically that the circuit is open or not functioning properly, which can affect the operation of the vehicle's emissions system

Common causes

  • Faulty reductant tank heater
  • Open or shorted wiring in the heater circuit
  • Bad connector or corroded terminals
  • Failed power supply to the heater
  • Faulty engine control module (ECM)
  • Blown fuse related to the reductant heater circuit

Common misdiagnoses

  • Faulty reductant tank heater
  • Open or shorted wiring in the circuit
  • Defective engine control module (ECM)
  • Faulty reductant temperature sensor
  • Issues with the reductant pump
  • Low reductant fluid level
  • Corroded connectors or terminals

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are multiple issues

  2. 2. Inspect the Reductant Tank Heater

    Visual Inspection: Check the reductant tank heater for any visible damage, corrosion, or loose connections

  3. 3. Wiring and Connectors

    Inspect the wiring harness and connectors for signs of wear, fraying, or corrosion. Ensure that all connections are secure

  4. 4. Test the Reductant Tank Heater

    Resistance Test: Use a multimeter to measure the resistance of the reductant tank heater. Compare the reading to the manufacturer's specifications. A reading outside the specified range may indicate a faulty heater

  5. 5. Power Supply

    Check if the heater is receiving the correct voltage when activated. If not, there may be an issue with the control circuit

  6. 6. Check the Control Circuit

    Fuses: Inspect the fuses related to the reductant system. Replace any blown fuses

  7. 7. Control Module

    If the heater and wiring are in good condition, the issue may lie with the engine control module (ECM) or the reductant control module. Check for software updates or faults in the module

  8. 8. Inspect the Reductant Fluid Level

    Ensure that the reductant (urea) tank is filled to the appropriate level. Low fluid levels can sometimes trigger related codes

  9. 9. Check for Ground Issues

    Ensure that the ground connections for the reductant tank heater and control circuit are clean and secure. Poor grounding can lead to circuit issues

  10. 10. Perform a System Reset

    After addressing any identified issues, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  11. 11. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues or fixes for the P202A code

  12. 12. Seek Professional Help

    If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle and its emissions system. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the P202A code