P21A1 - Cylinder 6 Air Fuel Ratio Imbalance

Powertrain DTC Charts and Descriptions 4-129

Diagnostic Trouble Code (DTC) Charts and Descriptions

P21A1 - Cylinder 6 Air Fuel Ratio Imbalance

Description: The air to fuel ratio imbalance torque monitor is designed to detect minimal differences in the air to fuel ratio

between cylinders. This DTC sets when the minimal air to fuel ratio difference in cylinder 6 is greater than a calculated amount.

Possible Causes: • Leaking or contaminated cylinder 6 fuel injector

• External noise sources on the CKP circuit such as the charging circuit or aftermarket equipment

• Electrical noise on the CKP circuit from radio frequency interference or electro magnetic interference

• 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

• Incorrectly seated engine oil dipstick, tube or oil fill cap

• Base engine concerns

Diagnostic Aids: This DTC may be caused by other systems related to cylinder 6. Diagnose any other cylinder 6 related DTCs

first. The crankshaft position (CKP) sensor signal is very sensitive to electrical noise. Check the routing of the CKP sensor wiring harness.

Application Key On Engine Off Key On Engine Running Continuous Memory

All GO to Pinpoint Test H.

P2227 - Barometric Pressure Sensor A Circuit Range/Performance

For Fiesta

Description: This DTC sets when there is an out of range condition in the BARO circuit.

Possible Causes: • Damaged barometric pressure (BARO) sensor

• Damaged PCM

Diagnostic Aids: The BARO sensor is integral to the PCM. A BARO reading less than 50 kPa (7.25 psi) indicates a concern.

Clear the PCM DTCs. Repeat the self-test. If the DTC is retrieved again, install a new PCM. Refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM).

For KA

Description: This DTC sets when there is an out of range condition in the BARO circuit.

Possible Causes: • Damaged barometric pressure (BARO) sensor

• Damaged PCM

Diagnostic Aids: The BARO sensor is integral to the PCM. A BARO reading less than 50 kPa (7.25 psi) indicates a concern.

Clear the PCM DTCs. Repeat the self-test. If the DTC is retrieved again, install a new PCM. Refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM).

For Vehicles With 2.7L And 3.5L GTDI Engines

Description: This DTC sets when either of the following conditions are present.

When the BARO PID does not correlate with the TCBP and the MAP PIDs at ignition ON, engine OFF. When the MAP and TCBP PIDs correlate with the engine running, but the TCBP PID does not correlate with the BARO PID at idle.

Possible Causes: • Damaged BARO sensor

• Damaged PCM

Diagnostic Aids: This DTC is only operational between 1,000 feet below sea level to 15,000 feet above sea level, it should be

disregarded if set outside the operational range.

For All Others

Description: This DTC sets when the BARO does not correlate with an inferred barometric pressure calculation based on the

MAP or mass airflow (MAF) value.

Possible Causes: • Damaged BARO sensor

• Damaged PCM

Diagnostic Aids: This DTC is only operational between 1,000 feet below sea level to 15,000 feet above sea level, it should be

disregarded if set outside the operational range.

Application Key On Engine Off Key On Engine Running Continuous Memory

Fiesta Refer to the Description, Possible Causes and Diagnostic Aids for the DTC.

2016 Powertrain Control/Emissions Diagnosis, Gasoline Engines, 3/2015