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.
4-26 Powertrain DTC Charts and Descriptions
Diagnostic Trouble Code (DTC) Charts and Descriptions
P0125 - Insufficient Coolant Temperature For Closed Loop Fuel Control (Continued)
Possible Causes: • Insufficient warm up time
• Low engine coolant level
• Leaking or stuck open thermostat
• Damaged ECT sensor
• Damaged CHT sensor
Diagnostic Aids: Compare the thermostat specification to the actual engine coolant temperature using the engine temperature
PID (ECT or CHT). The temperature reading should be similar when the engine is at a normal operating temperature.
Application Key On Engine Off Key On Engine Running Continuous Memory
EcoSport, GO to Pinpoint Test DX. Edge 2.0L, Edge 2.7L, Escape/Kuga 2.0L, Explorer 2.3L, F-150 2.7L, Fiesta, Focus, Fusion 1.5L, Fusion 2.0L, KA, MKC, MKT 2.0L, MKX 2.0L, MKX 2.7L, MKZ 2.0L, Mustang 2.3L, Taurus 2.0L, Transit Connect 1.6L
All others GO to Pinpoint Test DL.
P0128 - Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
Description: This DTC sets when the thermostat monitor has not achieved the required engine operating temperature within
a specified amount of time.
Possible Causes: • Insufficient warm up time
• Low engine coolant level
• Leaking or stuck open thermostat
• Damaged engine coolant temperature (ECT) sensor
• Damaged cylinder head temperature (CHT) sensor
Diagnostic Aids: Refer to Section 1, Thermostat Monitor for system information.
Application Key On Engine Off Key On Engine Running Continuous Memory
EcoSport, GO to Pinpoint Test DX. Edge 2.0L, Edge 2.7L, Escape/Kuga 2.0L, Explorer 2.3L, F-150 2.7L, Fiesta, Focus, Fusion 1.5L, Fusion 2.0L, KA, MKC, MKT 2.0L, MKX 2.0L, MKX 2.7L, MKZ 2.0L, Mustang 2.3L, Taurus 2.0L, Transit Connect 1.6L
All others GO to Pinpoint Test DL.
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.