Pinpoint Test E : OSS (Output Shaft Speed) Sensor

WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

Refer to Transmission Controls - 6R80 for schematic and connector information.

Normal Operation and Fault Conditions

The OSS sensor is a Hall-effect type sensor that provides a signal to the PCM that changes in frequency as the rotating speed of the output shaft ring gear varies. The PCM also compares the OSS sensor signal with the TSS sensor signal to determine the gear ratio provided by the rear planetary gearset. The PCM uses the OSS sensor signal as an input for its strategies for shifts and TCC operation. The PCM also uses the OSS sensor signal for transmission fault detection and diagnostics.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
PCM P0720:00	Output Shaft Speed Sensor Circuit: No Sub Type Information	This DTC indicates the OSS sensor failed to 0 speed when vehicle operating conditions indicate the output shaft should be rotating.
PCM P0721:00	Output Shaft Speed Sensor Circuit Range/Performance: No Sub Type Information	This DTC indicates an intermittent or noisy OSS sensor signal, or an unrealistic change in output shaft speed.
PCM P0722:00	Output Shaft Speed Sensor Circuit No Signal: No Sub Type Information	This DTC illuminates the wrench light in conjunction with DTC P0720. Resolve the more specific DTC first.

Possible Sources

Connectors damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals
Transmission internal wiring harness molded leadframe
PCM

E1 DRIVE CYCLE TEST

NOTE: Read and record all DTCs.

NOTE: If DTCs P0705, P0706, P0707, P0708, P0709, P1702, P1705 and/or P1921 are set, diagnose those DTCs first.
- Using the diagnostic scan tool, monitor the OSS sensor PID OSS_SRC while road testing the vehicle. Drive the vehicle so the transmission upshifts and downshifts through all the gears.
Does the OSS sensor rpm steadily increase and decrease with vehicle speed?

Yes The OSS sensor is working correctly at this time.

No GO to E2

E2 CHECK OSS SENSOR SIGNAL CIRCUIT FOR POWER

Ignition OFF.

Disconnect Transmission vehicle harness C1575.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1575-15	Courtesy of FORD MOTOR COMPANY	Ground

Is voltage present?

Yes

GO to E5

GO to E3

E3 CHECK THE OSS SENSOR SIGNAL CIRCUIT FOR AN OPEN

Ignition OFF.

Disconnect: PCM C1551T

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

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1575-15	Courtesy of FORD MOTOR COMPANY	C1551T-51

Is the resistance less than 3 ohms?

Yes

GO to E4

No	REPAIR the circuit.

E4 CHECK THE OSS SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1575-15	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes	Refer to PCM Guided Routine Testing . After installing a new PCM, CARRY OUT the transmission strategy download. REFER to: Transmission Strategy Download .

No	REPAIR the circuit.

E5 CHECK THE OSS SENSOR VPWR AND TR GND GROUND CIRCUITS

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C1575-12	Courtesy of FORD MOTOR COMPANY	C1575-11

Is voltage greater than 11 volts?

Yes	INSTALL a new molded leadframe. REFER to: Shift Solenoids (SS) .

No	INSPECT and REPAIR transmission vehicle harness OSS sensor power and ground circuits for an open. If an open circuit is not found, Refer to PCM Guided Routine Testing . After installing a new PCM, CARRY OUT the transmission strategy download. REFER to: Transmission Strategy Download .