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.

DTC ACTIVE
1. Turn the ignition on.
2. With the scan tool, View all active DTCs.
  Is the DTC active?
  
  Yes
  - Go To 2.
  No
  - Perform the INTERMITTENT CONDITION - 6.7L diagnostic procedure. Refer to INTERMITTENT CONDITION - 6.7L .
CHECK THE (K478) DEF PRESSURE LINE HEATER RETURN CIRCUIT FOR A SHORT TO GROUND

Fig 1: Checking The DEF Pressure Line Heater Return Circuit For A Short To Ground
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the DEF Supply/Purge Line Heater harness connector.
3. Disconnect the DEF Dosing Control Unit C1 harness connector.
4. Measure the resistance between ground and the (K478) DEF Pressure Line Heater Return circuit at the DEF Pressure Line Heater harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 3.
  No
  - Repair the (K478) DEF Pressure Line Heater Return circuit for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Refer to POWERTRAIN VERIFICATION TEST - 6.7L .
CHECK THE RESISTANCE OF THE DEF PRESSURE LINE HEATER
1. Measure the resistance across the terminals of the DEF Pressure Line Heater.
  Does the resistance measure between 5.74 Ohms and 6.88 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
  - Replace the DEF Pressure Line in accordance with the service information. Refer to LINE, Diesel Exhaust Fluid Pressure , Removal .
  - Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Refer to POWERTRAIN VERIFICATION TEST - 6.7L .