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.
4-126 Powertrain DTC Charts and Descriptions
Diagnostic Trouble Code (DTC) Charts and Descriptions
P2197 - O2 Sensor Signal Biased/Stuck Lean - Bank 2, Sensor 1 (Continued)
• Damaged universal HO2S21
• Damaged PCM
Diagnostic Aids:
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test H.
P2198 - O2 Sensor Signal Biased/Stuck Rich - Bank 2, Sensor 1
Description: A universal heated oxygen sensor bank 2, sensor 1 (HO2S21) indicating rich at the end of a test is trying to
correct for an over rich condition. This DTC sets when the fuel control system no longer detects switching for a calibrated amount of time.
Possible Causes: • Water in the harness connector
• UO2SPC21 circuit open
• Corrosion
• Incorrect connections
• Excessive fuel pressure
• Leaking or contaminated fuel injectors
• EVAP purge valve stuck open
• Biased MAP sensor signal
• Incorrect learned ethanol content
• Contaminated MAF sensor (if equipped)
• Positive crankcase ventilation (PCV) system
• Contaminated oil
• Oil overfill
• Camshaft timing
• Damaged universal HO2S21
• Damaged PCM
Diagnostic Aids:
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test H.
P219A - Bank 1 Air/Fuel Ratio Imbalance
Description: The air to fuel imbalance monitor is designed to detect large differences in the air to fuel ratio between cylinders
per engine bank. This DTC sets when the air to fuel ratio difference per cylinder is greater than a calculated amount.
Possible Causes: • Leaking or contaminated fuel injectors
• Low fuel pressure or running out of fuel
• Leaking EVAP purge valve
• Exhaust or intake air system leaks
• Exhaust gas recirculation (EGR) system
• Positive crankcase ventilation (PCV) system is leaking
• Ignition system
• Incorrectly seated engine oil dipstick, tube or oil fill cap
• Base engine concerns
• Damaged universal heated oxygen sensor bank 1, sensor 1 (HO2S11)
Diagnostic Aids: The EGR port is restricted.
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test H.
P219B - Bank 2 Air/Fuel Ratio Imbalance
Description: The air to fuel imbalance monitor is designed to detect large differences in the air to fuel ratio between cylinders
per engine bank. This DTC sets when the air to fuel ratio difference per cylinder is greater than a calculated amount.
Possible Causes: • Leaking or contaminated fuel injectors
• Low fuel pressure or running out of fuel
• Leaking EVAP purge valve
• Exhaust or intake air system leaks
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.