Diagnostic Test

WARNING: This page is about a different car, the 2011 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

ACTIVE DTC
1. Turn the ignition on, engine not running.
2. With the scan tool, View DTCs.
  Is the DTC active?
  
  Yes
  - Go To 2.
  No
  - Perform the INTERMITTENT CONDITION - 6.7L. Refer to INTERMITTENT CONDITION - 6.7L .
CHECK THE (K470) DEF PURGE VALVE SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE

Fig 1: Checking The DEF Purge Valve Signal Circuit For An Open Or High Resistance
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the DEF Supply Pump Assembly harness connector.
3. Disconnect the DEF Dosing Control Unit C1 harness connector.
4. Measure the resistance of the (K470) DEF Purge Valve Signal circuit between the DEF Supply Pump Assembly 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 (K470) DEF Purge Valve Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Refer to POWERTRAIN VERIFICATION TEST - 6.7L .
CHECK THE (K421) DEF PURGE VALVE RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE

Fig 2: Checking The DEF Purge Valve Return Circuit For An Open Or High Resistance
Courtesy of CHRYSLER LLC
1. Measure the resistance of the (K421) DEF Purge Valve Return circuit between the DEF Supply Pump Assembly harness connector and the DEF Dosing Control Unit C1 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 4.
  No
  - Repair the (K421) DEF Purge Valve Return circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Refer to POWERTRAIN VERIFICATION TEST - 6.7L .
CHECK THE DEF PURGE VALVE
1. Reconnect the DEF Dosing Control Unit C1 harness connector.
2. Connect a jumper between the (K470) DEF Purge Valve Signal circuit and the (K421) DEF Purge Valve Return circuit at the DEF Supply Pump Assembly harness connector.
  NOTE:
  Be careful not to spread the terminals.
3. Turn the ignition on.
4. With a scan tool, View DTCs.
  Did DTC P20A3 become active and DTC P20A0 change to stored with the jumper in place?
  
  Yes
  - Replace the DEF Supply Pump Assembly in accordance with the service information. Refer to ASSEMBLY, Diesel Exhaust Fluid Pump , Removal .
  - Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Refer to POWERTRAIN VERIFICATION TEST - 6.7L .
  No
  - Replace the DEF Dosing Control Unit in accordance with the service information. Refer to UNIT, Diesel Exhaust Fluid Dosing Control , Removal .
  - Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Refer to POWERTRAIN VERIFICATION TEST - 6.7L .