Diagnostic Test

TEST FOR INTERMITTENT CONDITION
1. Turn the ignition on.
2. Using the scan tool, record and erase FCM Diagnostic Trouble Codes (DTCs).
3. Cycle the ignition from on to off three times.
4. Turn the ignition on.
5. Using the scan tool, read active FCM DTCs.
  Does the scan tool display this DTC as active?
  
  Yes
  - Go to step 2
  No
  - The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
CHECK THE (D55) CAN B BUS (+) CIRCUIT FOR A SHORT TO VOLTAGE

Fig 1: Checking CAN B BUS (+) Circuit
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Front Control Module C1 harness connector.
3. Turn the ignition on.
4. Measure the voltage between the (D55) CAN B Bus (+) circuit and ground.
  Is voltage above 10.0 volts?
  
  Yes
  - Go to step 3
  No
  - Inspect the wiring and connectors for damage or shorted circuits. If ok, replace the Front Control Module in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
(D55) CAN B BUS (+) CIRCUIT SHORTED TO VOLTAGE

Fig 2: Checking CAN B BUS (+) Circuit
Courtesy of CHRYSLER LLC
1. Measure the voltage between the (D55) CAN B Bus (+) circuit and ground.
2. While monitoring the voltmeter, disconnect each CAN B Bus module one at a time.
  NOTE: When performing the above step, turn the ignition off (wait one minute) before disconnecting any module. When the module is disconnected, turn the ignition on to check for a short to voltage.
  
  NOTE: This is to determine if the short to voltage is internal within a module or if the circuit is shorted.
  
  NOTE: Disconnecting an in-line connector can eliminate a module or group of modules from the list of possible causes for this fault. Refer to the wiring diagrams to assist in diagnosis.
  
  Is the voltage above 10.0 volts with all the CAN B Bus modules disconnected?
  
  Yes
  - Repair the (D55) CAN B Bus (+) circuit for a short to voltage.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
  No
  - Replace the module that when disconnected, the short to voltage was eliminated, in accordance with the Service Information.
  - Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .