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 DEF PURGE VALVE
1. Turn the ignition off.
2. Disconnect the DEF Supply Pump Assembly harness connector.
3. Turn the ignition on.
4. With a scan tool, View DTCs.
  Did DTC P20A0 become active and DTC P20A3 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
  - Go To 3.
CHECK FOR THE (K421) DEF PURGE VALVE RETURN CIRCUIT SHORTED TO ANOTHER CIRCUIT

Fig 1: Checking DEF Purge Valve Return Circuit For A Short To Another Circuit
Courtesy of CHRYSLER LLC
1. Disconnect the DEF Dosing Control Unit C1 harness connector.
2. Measure the resistance between the (K421) DEF Purge Valve Return circuit and all other circuits at the DEF Dosing Control Unit C1 harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - 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 .
  No
  - Repair the (K421) DEF Purge Valve Return circuit for a short to the circuit that measured below 10k Ohms.
  - Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Refer to POWERTRAIN VERIFICATION TEST - 6.7L .