Diagnostic Test

WARNING: This page is about a different car, the 2015 RAM 1500. However, it is still accessible from the selected car via links, so may be relevant.

DTC IS ACTIVE
1. Ignition on, engine not running.
2. With the scan tool, select View DTCs.
  Is the status Active for this DTC?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT DTC .
CHECK THE (K646) FUEL PRESSURE REGULATOR CONTROL CIRCUIT FOR A SHORT TO GROUND

Fig 1: Checking Fuel Pressure Regulator Control Circuit For A Short To Ground
Courtesy of CHRYSLER GROUP, LLC
1. Turn the ignition off.
2. Disconnect the Fuel Pressure Regulator harness connector.
3. Disconnect the PCM C2 harness connector.
4. Measure the resistance between ground and the (K646) Fuel Pressure Regulator Control circuit in the Fuel Pressure Regulator harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 3
  No
  - Repair the (K646) Fuel Pressure Regulator Control circuit for a short to ground.
  - Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
CHECK FOR THE (K646) FUEL PRESSURE REGULATOR CONTROL CIRCUIT FOR A SHORT TO THE (K369) FUEL PRESSURE REGULATOR RETURN CIRCUIT

Fig 2: Checking Fuel Pressure Regulator Control Circuit For Short To Fuel Pressure Regulator Return Circuit
Courtesy of CHRYSLER GROUP, LLC
1. Measure the resistance between the (K646) Fuel Pressure Regulator Control circuit and the (K369) Fuel Pressure Regulator Return circuit at the Fuel Pressure Regulator harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the (K646) Fuel Pressure Regulator Control circuit for a short to the (K369) Fuel Pressure Regulator Return circuit.
  - Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
FUEL PRESSURE REGULATOR
1. Reconnect the Fuel Pressure Regulator harness connector.
2. Reconnect the Powertrain Control Module C2 harness connector.
3. Turn the ignition on.
4. With the scan tool, erase DTCs.
5. Turn the ignition off.
6. Disconnect the Fuel Pressure Regulator harness connector.
7. Turn the ignition on.
8. With the scan tool, select View DTCs.
  NOTE:
  The scan tool should display a P0090-FUEL PRESSURE CONTROL CIRCUIT OPEN DTC as active or pending with the connector disconnected.
  
  Did the scan tool display the DTC as described above?
  
  Yes
  - Replace the Fuel Pressure Regulator in accordance with the service information. Refer to SOLENOID, FUEL PRESSURE, REMOVAL .
  - Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  No
  - Go To 5
POWERTRAIN CONTROL MODULE
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Fuel Pressure Regulator and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Perform any Technical Service Bulletins that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  No
  - Replace and program the Powertrain Control Module in accordance the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .