DTC Code P202B – What does this code mean?

<ul> <li><a href="/problems/vw-check-engine-light-is-on"><b>Engine Light ON</b></a>: The check engine light or service engine soon warning light illuminates, indicating a potential issue with the reductant tank heater control circuit.</li> <li><b>Poor Emission Control</b>: The vehicle may experience reduced efficiency in emission control, potentially leading to increased emissions due to the malfunctioning reductant tank heater.</li> <li><b>Cold Weather Performance Issues</b>: In colder climates, the reductant tank heater may not function properly, leading to issues with the DEF (Diesel Exhaust Fluid) freezing, which can affect vehicle performance.</li> </ul>

<ul><li>The reductant tank heater may be faulty, leading to inadequate heating and potential freezing of the reductant fluid.</li><li>An open or shorted harness in the reductant tank heater can disrupt the electrical flow, causing the control circuit to register a low signal.</li><li>Poor electrical connections in the reductant tank heater circuit can result in insufficient power supply, triggering the error code.</li></ul>

<ul> <li><b>Initial Inspection</b>: Visually inspect the reductant tank heater and its wiring for any signs of damage, corrosion, or disconnection. Ensure all connectors are securely attached.</li> <li><b>Check Voltage Supply</b>: Using a multimeter, measure the voltage at the reductant tank heater connector. Verify that the voltage is within the specified range as per Volkswagen's service manual.</li> <li><b>Test Heater Resistance</b>: Disconnect the heater and measure its resistance with an ohmmeter. Compare the reading to the manufacturer's specifications to ensure the heater is functioning correctly.</li> <li><b>Inspect Control Circuit</b>: Examine the control circuit for any open or short circuits. Use a wiring diagram to trace the circuit and ensure continuity.</li> <li><b>Check Control Module</b>: Verify the functionality of the control module responsible for the reductant tank heater. Ensure it is sending the correct signals and is not faulty.</li> <li><b>Perform ECU Scan</b>: Use a diagnostic scanner to check for any additional codes or issues related to the ECU that may affect the reductant tank heater operation.</li></ul>

<p>The DTC P202B for Volkswagen indicates a <b>Reductant Tank Heater Control Circuit Low</b>. This issue can lead to <ul><li>inefficient DEF (Diesel Exhaust Fluid) heating</li><li>potential freezing in cold climates</li></ul>. If not addressed, it may result in <b>increased emissions</b> and <b>reduced engine performance</b>. Immediate attention is advised to prevent further complications.</p>