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Home >> Chrysler >> 2011 >> 300 C, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1574 (6.7L Diesel - DTCS P20B7 To P24A0 - 2500 Hd) >> DTC Troubleshooting >> P20B7-(Diesel Exhaust Fluid) REDUCTANT Pump Heater Control Circuit Low >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2017 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
  1. ACTIVE DTC 
    NOTE:

    If DTC P21CA, P21CB, or P21CC are also active, diagnose and repair that DTC before continuing with this test procedure.

    1. Turn the ignition on, engine not running.
    2. With the scan tool, actuate the DEF Line Heater or Tank Heater Override Test.
    3. With the scan tool, View DTCs.

      Is the DTC Active?

      Yes 

      • Go To  2

      No 

  2. CHECK THE (F203) SCR MODULE HEATER SUPPLY CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Disconnect the PDC C5 harness connector.
    3. Disconnect the DEF Dosing Control Unit C1 harness connector.
    4. Measure the resistance of the (F203) SCR Module Heater Supply circuit between the PDC C5 harness connector and the DEF Dosing Control Unit C1 harness connector.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  3

      No 

      • Repair the (F203) SCR Module Heater Supply circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  3. CHECK THE (Z905) SCR HEATER RELAY 1 GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure for continuity between (Z905) SCR Heater Relay 1 Ground circuit between the PDC C5 harness connector and ground.

      Is there continuity between (Z905) SCR Heater Relay 1 Ground circuit and ground?

      Yes 

      • Go To  4

      No 

      • Repair the (Z905) SCR Heater Relay 1 Ground circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  4. CHECK THE (F203) SCR MODULE HEATER SUPPLY CIRCUIT FOR A SHORT TO GROUND 
    1. Measure the resistance between ground and the (F203) SCR Module Heater Supply circuit at the DEF Dosing Control Unit C1 harness connector.

      Is the resistance above 10k Ohms?

      Yes 

      • Go To  5

      No 

      • Repair the (F203) SCR Module Heater Supply circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  5. CHECK THE PDC OUTPUT 
    1. Reconnect the PDC C5 harness connector.
    2. Turn the ignition on and start the engine.
    3. Measure the voltage of the (F203) SCR Module Heater Supply circuit at the DEF Dosing Control Unit C1 harness connector.

      Is the voltage approximately equal to battery voltage?

      Yes 

      • Replace the DEF Dosing Control Unit in accordance with the service information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Check two fuses (F19-30A and F75-10A) in the PDC that both feed the SCR 1 (Heater) Relay for an open. Check the connectors at the DEF Dosing Control Unit and PDC for spread terminals causing an intermittent connection. If the fuses and connectors are good, replace the Power Distribution Center (PDC) in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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