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Home >> Chrysler >> 2011 >> 300 Base, Gas >> Repair and Diagnosis >> External Pages >> Different car >> Section 100 (6.7L Diesel - DTCS - P21C4 To U1601 - 3500 Cab & Chassis) >> Diagnosis and Testing >> P21C4-(Diesel Exhaust Fluid) REDUCTANT Line Heater Relay Control Circuit High >> Code Description >> Possible Causes

Possible Causes

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Possible Causes 
(K475) DEF LINE HEATER RELAY SIGNAL CIRCUIT SHORTED TO VOLTAGE
(K429) DEF LINE HEATER RELAY CONTROL CIRCUIT SHORTED TO VOLTAGE
DEF LINE HEATER RELAY
DEF DOSING CONTROL UNIT

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Refer to  PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE - 6.7L  . 

NOTE:

The DEF Line Heater monitor runs only when the DEF Line Heater Relay is commanded on. If the ambient temperature is too warm for the DEF Line Heaters to be turned on, the DTC will remain active and will not be able to be erased after repair is completed. Using the scan tool, navigate to Actuator Tests and actuate the Line Heater Relay test for the appropriate Line Heater to run the diagnostic and determine if the repair has been completed. If the repair is complete, the fault will move to stored and be able to be cleared with the scan tool.