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.
4-142 Powertrain DTC Charts and Descriptions
Diagnostic Trouble Code (DTC) Charts and Descriptions
Pxxxx -
Description:
Possible Causes:
Diagnostic Aids: For Pxxxx DTCs not listed in this chart, refer to the customer's symptom to determine the applicable Workshop
Manual section for diagnosis.
Application Key On Engine Off Key On Engine Running Continuous Memory
All Refer to the Description, Possible Causes and Diagnostic Aids for the DTC.
U0046 - Vehicle Communication Bus C
Description:
Possible Causes:
Diagnostic Aids: Refer to the Workshop Manual Section 303-14, Electronic Engine Controls, PCM DTC Chart, to continue
diagnosis.
Application Key On Engine Off Key On Engine Running Continuous Memory
All Refer to the Description, Possible Causes and Diagnostic Aids for the DTC.
U0101 - Lost Communication With TCM
Description: The PCM continuously monitors the controller area network (CAN) for messages from the transmission control
module (TCM). This DTC sets when the PCM does not receive the TCM 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.
U0104 - Lost Communication With Cruise Control Module
Description: The PCM continuously monitors for messages from the cruise control module. This DTC sets when the PCM
does not receive the cruise control module 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.
U0109 - Lost Communication With Fuel Pump Control Module A
Description: The PCM monitors the fuel pump monitor (FPM) circuit for the presence of a duty cycled signal. If the FPM
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 FPM circuit after a calibrated amount of time.
Possible Causes: • FPM circuit open or short to ground
• FPM circuit short to voltage
• VPWR fuel circuit open
• GND circuit open
• Damaged inertia fuel shutoff (IFS) switch (if equipped)
• Damaged fuel pump control module relay
Diagnostic Aids: Check if the inertia fuel shutoff (IFS) switch is tripped.
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test KC.
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.