Fix P202A: STEP-BY-STEP diagnostic GUIDE!

The P202A: Reductant Tank Heater Control Circuit/Open code indicates an issue with the control circuit for the reductant (DEF/AdBlue) tank heater, such as an open circuit. This could be caused by a faulty heater control unit, wiring issues, or a damaged connector.

P202A – Quick Overview

CodeInformation
MeaningP202A: Reductant Tank Heater Control Circuit/Open
Is it serious?Yes, if the reductant tank heater fails, DEF fluid may freeze in cold weather, affecting the vehicle’s emission reduction system.
Possible causes– Open circuit in the reductant tank heater control
– Faulty heater control
– Wiring or connector issues
How to diagnose?– Inspect and test the heater control circuit
– Check the heater control unit
– Inspect wiring and connectors for damage

P202A Meaning

The P202A: Reductant Tank Heater Control Circuit/Open code signifies that there is an issue with the control circuit of the reductant tank heater. The heater is responsible for warming the DEF (Diesel Exhaust Fluid) tank to prevent freezing in cold conditions, which is essential for the proper functioning of the emission control system. An open or faulty circuit can prevent the heater from working.

Step-by-step diagnostic guide

ActionDescriptionTools Needed
Check for Other CodesUse an OBD-II scanner to check for other related codes. Additional codes may provide further details on the root cause of the issue with the reductant system or heater.OBD-II Scanner
Inspect the Heater Control CircuitUse a multimeter to test the control circuit for the reductant tank heater. Measure voltage and continuity in the circuit to detect any breaks or open circuits.Multimeter
Test the Heater Control UnitTest the reductant tank heater control unit to ensure it is functioning properly. A faulty control unit can prevent the heater from receiving power, causing the open circuit issue.Diagnostic Tool, Multimeter
Inspect Wiring and ConnectorsVisually inspect all wiring and connectors related to the heater control unit and the reductant tank heater. Look for signs of corrosion, damage, or disconnections that could cause an open circuit.Flashlight, Multimeter
Test Circuit ContinuityPerform a continuity test on the wiring leading to the reductant tank heater. Check for shorts, high resistance, or broken wires that may be causing the open circuit.Multimeter
Inspect the Reductant Tank HeaterInspect the reductant tank heater itself to ensure that it is operational. If it has failed, it may need to be replaced to restore proper heating in the reductant tank.Diagnostic Tool, Flashlight
Repair or Replace Damaged ComponentsRepair any damaged wiring, connectors, or control units. If the heater or its control system is faulty, replace the necessary components to restore full functionality.Wiring Repair Kit, Heater Replacement Kit
Clear the Code and Test DriveAfter completing repairs, clear the P202A code using an OBD-II scanner. Test drive the vehicle and monitor the heater system to ensure the issue has been resolved.OBD-II Scanner, Vehicle Owner’s Manual
Recheck for CodesAfter the test drive, re-scan the vehicle to verify that the P202A code has not returned.OBD-II Scanner
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