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.
4-114 Powertrain DTC Charts and Descriptions
Diagnostic Trouble Code (DTC) Charts and Descriptions
P164B - O2 Sensor Positive Current Trim Circuit Performance (Bank 2 Sensor 1)
Description: A resistor is installed in the universal heated oxygen sensor bank 2, sensor 1 (HO2S21) connector for part to
part variance. The PCM determines the value of this resistor by taking multiple measurements of the resistor during each ignition ON event. The PCM uses this value to compensate for the variance in the pumping current signal. This DTC sets when the PCM receives an inconsistent or erratic measurement of the resistor.
Possible Causes: • Corrosion
• Incorrect connections
• Damaged universal HO2S21
Diagnostic Aids:
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test DZ.
P164C - Internal Control Module Start-Stop Performance
Description: This DTC sets when an error occurs in the PCM.
Possible Causes: • Module programming error
• Aftermarket performance products
• Damaged PCM
Diagnostic Aids: This DTC may be accompanied by other DTCs. Check for other DTCs and diagnose those first. If no DTCs are
present, continue to follow diagnosis for this DTC.
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test AA.
P166A - Restraints Deployment Communication Circuit
Description: This DTC sets when the PCM detects an open or short in the IES circuit.
Possible Causes: • IES circuit open
• IES circuit short to ground
• IES circuit short to voltage
Diagnostic Aids:
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test KC.
P1674 - Control Module Software Corrupted
Description: This DTC sets when an error occurs in the PCM.
Possible Causes: • Software incompatibility issue
• Damaged PCM
Diagnostic Aids: Verify the PCM is at the latest calibration level.
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test QE.
P1698 - Cold Start Fuel Pump Primary Circuit/Open
Description: This DTC sets when the cold start relay control circuit indicates the expected voltage value is less than the
calibrated threshold.
Possible Causes: • Cold start fuel relay
• CSRC circuit open
• CSRC circuit short to ground
• B+ circuit open
• B+ circuit short to ground
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.