Vehicle applicability: This diagnostic supplement covers multiple Ford vehicles and engines. Follow the application named in the source below. Some references apply to vehicles other than Mustang.
Powertrain DTC Charts and Descriptions 4-143
Diagnostic Trouble Code (DTC) Charts and Descriptions
U0121 - Lost Communication With Anti-lock Brake System (ABS) Control Module
Description: The PCM continuously monitors the controller area network (CAN) for messages from the ABS. This DTC sets
when the PCM fails to receive the ABS message within the defined amount of time.
Possible Causes: • Communication error
Diagnostic Aids: Check for other PCM DTCs or PCM related symptoms. Diagnose all other PCM DTCs or PCM related
symptoms first.
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test QA.
U0138 - Lost Communication With All Terrain Control Module
Description: The PCM continuously monitors the controller area network (CAN) for messages from the all terrain control
module (ATCM). This DTC sets when the PCM does not receive the ATCM message within the defined amount of time.
Possible Causes: • Communication error
Diagnostic Aids: Check for other PCM DTCs or PCM related symptoms. Diagnose all other PCM DTCs or PCM related
symptoms first.
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test QA.
U0140 - Lost Communication With Body Control Module
Description: The PCM continuously monitors controller area network (CAN) for messages from body control module (BCM).
This DTC sets when the PCM does not receive the BCM message within the defined amount of time.
Possible Causes: • Communication error
Diagnostic Aids: Check for other PCM DTCs or PCM related symptoms. Diagnose all other PCM DTCs or PCM related
symptoms first.
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test QA.
U0155 - Lost Communication With Instrument Panel Cluster Control Module
Description: The PCM continuously monitors the controller area network (CAN) for messages from the instrument panel
cluster (IPC) module. This DTC sets when the PCM does not receive the IPC message within the defined amount of time.
Possible Causes: • Communication error
Diagnostic Aids: Check for other PCM DTCs or PCM related symptoms. Diagnose all other PCM DTCs or PCM related
symptoms first.
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test QA.
U016C - Lost Communication With Fuel Pump Control Module B
Description: The PCM monitors the FPM2 circuit for the presence of a duty cycled signal. If the FPM2 circuit is fixed at a low
or high voltage, the PCM begins to increment a counter. This DTC sets when the PCM is still not detecting a duty cycled signal on the FPM2 circuit after a calibrated amount of time.
Possible Causes: • FPM2 circuit open or short to ground
• FPM2 circuit short to voltage
• VPWR fuel circuit open
• GND circuit open
• Damaged fuel pump control module relay 2
Diagnostic Aids:
Application Key On Engine Off Key On Engine Running Continuous Memory
2016 Powertrain Control/Emissions Diagnosis, Gasoline Engines, 3/2015
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.