The P202C: Reductant Tank Heater Control Circuit High refers to an issue where the voltage in the reductant tank heater control circuit is higher than expected. This can be caused by a faulty heater control unit, high voltage in the circuit, or wiring and connector issues.
P202C – Quick Overview
| Code | Information |
|---|---|
| Meaning | P202C: Reductant Tank Heater Control Circuit High |
| Is it serious? | Yes, high voltage in the circuit can prevent the reductant tank heater from functioning properly, which can lead to DEF (Diesel Exhaust Fluid) freezing in cold conditions, affecting the emission system. |
| Possible causes | – High voltage in the heater control circuit – Faulty heater control – Wiring or connector issues |
| How to diagnose? | – Measure voltage in the heater control circuit – Test the heater control unit – Inspect wiring and connectors |
P202C Meaning
The P202C: Reductant Tank Heater Control Circuit High code indicates that the voltage in the reductant tank heater control circuit is higher than the manufacturer’s specified range. The reductant tank heater prevents the DEF from freezing in cold weather, ensuring the vehicle’s emission system functions properly. High voltage in the control circuit may prevent the heater from operating correctly.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for any additional codes related to the reductant tank heater or other components of the emission system. These may provide more context. | OBD-II Scanner |
| Measure Voltage in the Heater Control Circuit | Use a multimeter to measure the voltage in the reductant tank heater control circuit. Compare the voltage readings to manufacturer specifications to verify if the voltage is too high. | Multimeter |
| Test the Heater Control Unit | Use a diagnostic tool to test the heater control unit. If the control unit is malfunctioning and providing excessive voltage, it may need to be replaced. | Diagnostic Tool, Multimeter |
| Inspect Wiring and Connectors | Visually inspect all wiring and connectors associated with the heater control circuit. Look for any signs of damage, corrosion, or loose connections that could be causing excessive voltage. | Flashlight, Multimeter |
| Test Circuit Continuity | Perform a continuity test on the wiring leading to the reductant tank heater. Ensure there are no shorts or high resistance causing high voltage in the circuit. | Multimeter |
| Inspect the Reductant Tank Heater | Check the reductant tank heater itself to ensure it is functioning properly. If it is receiving too much voltage, it may need to be replaced. | Diagnostic Tool, Flashlight |
| Repair or Replace Damaged Components | If you find any damaged wiring, connectors, or a faulty control unit, repair or replace them to restore proper operation of the reductant tank heater circuit. | Wiring Repair Kit, Heater Replacement Kit |
| Clear the Code and Test Drive | After repairs are completed, clear the P202C code using an OBD-II scanner. Take the vehicle for a test drive and monitor the system to ensure the issue has been resolved. | OBD-II Scanner, Vehicle Owner’s Manual |
| Recheck for Codes | After the test drive, re-scan the vehicle to verify that the P202C code has not returned. | OBD-II Scanner |
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