Pinpoint Test P: DTC P271A

Normal Operation and Fault Conditions

The park pawl motor moves a park pawl rod when energized, moving the park pawl out of the Park position. When the park pawl is in the out of park position, the park pawl motor turns off and a hold out of park (HOOP) solenoid energizes and holds the park pawl out of Park. When power is turned off to the HOOP solenoid a spring returns the park pawl to the Park position. The park pawl actuator uses dual PWM output (at 1000 Hz) park pawl position sensors where sensor A increases as the park pawl moves out of Park and sensor B decreases. Together the sum of the two PWM signal duty cycles should add up to approximately 100%. A rotary sensor measures the position of a cam actuator that moves the linear park pawl rod and determines whether the park pawl actuator is in the "Stay out of Park" mode.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
SOBDMC P271A:00	Park Pawl Position Sensor "A" Circuit Low: No Sub Type Information	This DTC indicates a short to ground or an open in rotary position sensor "A" circuit.

Possible Sources

Connectors damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals
Circuit open or shorted
Park lock actuator
SOBDMC

P1 RETRIEVE AND RECORD ALL DTCS

Using the diagnostic scan tool, retrieve all diagnostic trouble codes (DTCs).

Is DTC P271A present?

Yes

GO to P2

No	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or terminal issues.

P2 CHECK THE ROTARY SENSOR VREF CIRCUIT FOR VOLTAGE

Ignition OFF.

Disconnect Rear electric drive assembly C400.

Inspect the connector for damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C400-39	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage between 4.8 and 5.2 volts?

Yes

GO to P7

GO to P3

P3 CHECK THE ROTARY SENSOR VREF CIRCUIT FOR AN OPEN

Ignition OFF.

Disconnect SOBDMC C3471D.

Inspect the connector for damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C400-39	Courtesy of FORD MOTOR COMPANY	C3471D-36

Is the resistance less than 3 ohms?

Yes

GO to P4

No	REPAIR the open circuit.

P4 CHECK THE ROTARY SENSOR VREF CIRCUIT FOR A SHORT TO GROUND

Measure:

Positive Lead	Measurement / Action	Negative Lead
C400-39	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to P5

No	REPAIR the short to ground.

P5 CHECK THE ROTARY SENSOR VREF CIRCUIT FOR A SHORT TOGETHER WITH THE POWER CIRCUITS

Measure:

Positive Lead	Measurement / Action	Negative Lead
C400-39	Courtesy of FORD MOTOR COMPANY	C400-1
C400-39	Courtesy of FORD MOTOR COMPANY	C400-8
C400-39	Courtesy of FORD MOTOR COMPANY	C400-11
C400-39	Courtesy of FORD MOTOR COMPANY	C400-14
C400-39	Courtesy of FORD MOTOR COMPANY	C400-15
C400-39	Courtesy of FORD MOTOR COMPANY	C400-18
C400-39	Courtesy of FORD MOTOR COMPANY	C400-21
C400-39	Courtesy of FORD MOTOR COMPANY	C400-28
C400-39	Courtesy of FORD MOTOR COMPANY	C400-29
C400-39	Courtesy of FORD MOTOR COMPANY	C400-31
C400-39	Courtesy of FORD MOTOR COMPANY	C400-31
C400-39	Courtesy of FORD MOTOR COMPANY	C400-34
C400-39	Courtesy of FORD MOTOR COMPANY	C400-35
C400-39	Courtesy of FORD MOTOR COMPANY	C400-38
C400-39	Courtesy of FORD MOTOR COMPANY	C400-40

Are the resistances all greater than 10, 000 ohms?

Yes

GO to P6

No	REPAIR the shorted circuits.

P6 RECHECK THE ROTARY SENSOR VREF CIRCUIT FOR VOLTAGE

Connect SOBDMC C3471D.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C400-39	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage between 4.8 and 5.2 volts?

Yes	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or terminal issues.

No	INSTALL a new SOBDMC. REFER to: Inverter System Controller [SOBDMC] .

P7 CHECK THE ROTARY SENSOR SIGNAL CIRCUIT FOR AN OPEN

Ignition OFF.

Disconnect SOBDMC C3471D.

Inspect the connector for damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C400-28	Courtesy of FORD MOTOR COMPANY	C3471D-15

Is the resistance less than 3 ohms?

Yes

GO to P8

No	REPAIR the open circuit.

P8 CHECK THE ROTARY SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND

Measure:

Positive Lead	Measurement / Action	Negative Lead
C400-28	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to P9

No	REPAIR the short to ground.

P9 CHECK THE ROTARY SENSOR SIGNAL CIRCUIT FOR A SHORT TOGETHER WITH THE POWER CIRCUITS

Measure:

Positive Lead	Measurement / Action	Negative Lead
C400-28	Courtesy of FORD MOTOR COMPANY	C400-1
C400-28	Courtesy of FORD MOTOR COMPANY	C400-8
C400-28	Courtesy of FORD MOTOR COMPANY	C400-11
C400-28	Courtesy of FORD MOTOR COMPANY	C400-14
C400-28	Courtesy of FORD MOTOR COMPANY	C400-15
C400-28	Courtesy of FORD MOTOR COMPANY	C400-18
C400-28	Courtesy of FORD MOTOR COMPANY	C400-21
C400-28	Courtesy of FORD MOTOR COMPANY	C400-29
C400-28	Courtesy of FORD MOTOR COMPANY	C400-31
C400-28	Courtesy of FORD MOTOR COMPANY	C400-31
C400-28	Courtesy of FORD MOTOR COMPANY	C400-34
C400-28	Courtesy of FORD MOTOR COMPANY	C400-35
C400-28	Courtesy of FORD MOTOR COMPANY	C400-38
C400-28	Courtesy of FORD MOTOR COMPANY	C400-39
C400-28	Courtesy of FORD MOTOR COMPANY	C400-40

Are the resistances all greater than 10, 000 ohms?

Yes

GO to P10

No	REPAIR the shorted circuits.

P10 CHECK THE ROTARY SENSOR GROUND CIRCUIT FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C400-20	Courtesy of FORD MOTOR COMPANY	C3471D-19

Is the resistance less than 3 ohms?

Yes

GO to P11

No	REPAIR the open circuit.

P11 CHECK THE ROTARY SENSOR GROUND CIRCUIT FOR A SHORT TOGETHER WITH THE POWER CIRCUITS

Measure:

Positive Lead	Measurement / Action	Negative Lead
C400-20	Courtesy of FORD MOTOR COMPANY	C400-1
C400-20	Courtesy of FORD MOTOR COMPANY	C400-8
C400-20	Courtesy of FORD MOTOR COMPANY	C400-11
C400-20	Courtesy of FORD MOTOR COMPANY	C400-14
C400-20	Courtesy of FORD MOTOR COMPANY	C400-15
C400-20	Courtesy of FORD MOTOR COMPANY	C400-18
C400-20	Courtesy of FORD MOTOR COMPANY	C400-21
C400-20	Courtesy of FORD MOTOR COMPANY	C400-28
C400-20	Courtesy of FORD MOTOR COMPANY	C400-29
C400-20	Courtesy of FORD MOTOR COMPANY	C400-31
C400-20	Courtesy of FORD MOTOR COMPANY	C400-31
C400-20	Courtesy of FORD MOTOR COMPANY	C400-34
C400-20	Courtesy of FORD MOTOR COMPANY	C400-35
C400-20	Courtesy of FORD MOTOR COMPANY	C400-38
C400-20	Courtesy of FORD MOTOR COMPANY	C400-39
C400-20	Courtesy of FORD MOTOR COMPANY	C400-40

Are the resistances all greater than 10, 000 ohms?

Yes

GO to P12

No	REPAIR the circuit.

P12 CHECK THE REAR ELECTRIC DRIVE ASSEMBLY INTERNAL WIRING HARNESS ROTARY SENSOR VREF CIRCUIT FOR AN OPEN

Remove the transmission case end cover. REFER to: Park Lock Actuator .

Disconnect Park lock actuator C1015A.

Measure:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY Rear electric drive assembly connector, component side pin 39	Courtesy of FORD MOTOR COMPANY

Is the resistance less than 3 ohms?

Yes

GO to P13

No	INSTALL a new rear electric drive assembly. REFER to: Rear Electric Drive Assembly .

P13 CHECK THE REAR ELECTRIC DRIVE ASSEMBLY INTERNAL WIRING HARNESS ROTARY SENSOR VREF CIRCUIT FOR A SHORT TO GROUND

Measure:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY Rear electric drive assembly connector, component side pin 39	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to P14

No	INSTALL a new rear electric drive assembly. REFER to: Rear Electric Drive Assembly .

P14 CHECK THE REAR ELECTRIC DRIVE ASSEMBLY INTERNAL WIRING HARNESS ROTARY SENSOR VREF CIRCUIT FOR A SHORT TOGETHER WITH THE POWER CIRCUITS

Measure:

Are the resistances all greater than 10, 000 ohms?

Yes

GO to P15

No	INSTALL a new rear electric drive assembly. REFER to: Rear Electric Drive Assembly .

P15 CHECK THE REAR ELECTRIC DRIVE ASSEMBLY INTERNAL WIRING HARNESS ROTARY SENSOR SIGNAL CIRCUIT FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
Rear electric drive assembly connector, component side pin 28	Courtesy of FORD MOTOR COMPANY

Is the resistance less than 3 ohms?

Yes

GO to P16

No	INSTALL a new rear electric drive assembly. REFER to: Rear Electric Drive Assembly .

P16 CHECK THE REAR ELECTRIC DRIVE ASSEMBLY INTERNAL WIRING HARNESS ROTARY SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND

Measure:

Positive Lead	Measurement / Action	Negative Lead
Rear electric drive assembly connector, component side pin 28	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to P17

No	INSTALL a new rear electric drive assembly. REFER to: Rear Electric Drive Assembly .

P17 CHECK THE REAR ELECTRIC DRIVE ASSEMBLY INTERNAL WIRING HARNESS ROTARY SENSOR SIGNAL CIRCUIT FOR A SHORT TOGETHER WITH THE POWER CIRCUITS

Measure:

Are the resistances all greater than 10, 000 ohms?

Yes

GO to P18

No	INSTALL a new rear electric drive assembly. REFER to: Rear Electric Drive Assembly .

P18 CHECK THE REAR ELECTRIC DRIVE ASSEMBLY INTERNAL WIRING HARNESS ROTARY SENSOR GROUND CIRCUIT FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
Rear electric drive assembly connector, component side pin 20	Courtesy of FORD MOTOR COMPANY

Is the resistance less than 3 ohms?

Yes

GO to P19

No	INSTALL a new rear electric drive assembly. REFER to: Rear Electric Drive Assembly .

P19 CHECK THE REAR ELECTRIC DRIVE ASSEMBLY INTERNAL WIRING HARNESS ROTARY SENSOR GROUND CIRCUIT FOR A SHORT TOGETHER WITH THE POWER CIRCUITS

Measure:

Are the resistances all greater than 10, 000 ohms?

Yes	INSTALL a new park lock actuator. REFER to: Park Lock Actuator .

No	INSTALL a new rear electric drive assembly. REFER to: Rear Electric Drive Assembly .