Pinpoint Test C: OSS Sensor

WARNING: This page is about a different car, the 2010 Mercury Milan and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Refer to the transaxle connector illustrations and solenoid body leadframe internal wiring diagram TRANSAXLE CONNECTOR LAYOUTS .

NOTE: Output Shaft Speed (OSS) codes may be a result of a bad common power or ground shared between the Transmission Range (TR) sensor, OSS sensor and Turbine Shaft Speed (TSS) sensor.

C1 ELECTRONIC DIAGNOSTICS
- Check to make sure the transaxle vehicle harness C168a is fully seated, terminals are engaged in connector and in good condition before proceeding.
- Have the items above been checked?
- Yes : GO to C2 .
- No : CARRY OUT the checks. ERASE the codes. RERUN the On-Board Diagnostic (OBD) tests.
C2 ELECTRONIC DIAGNOSTICS
- Connect the scan tool.
- Monitor the OSS sensor PIDs while test driving the vehicle.
- Is the OSS sensor signal present and consistent?
- Yes : The condition that set the DTC is intermittent and is not currently present. ERASE the codes. RERUN the OBD tests.
- No : GO to C3 .

C3 CHECK THE VEHICLE HARNESS FOR AN OPEN CIRCUIT

Disconnect: Transaxle Vehicle Harness C168a.
Disconnect: PCM Transaxle Harness C175T.
Use a mirror to inspect both ends of the connectors for damage or pushed-out pins, corrosion, loose wires and missing or damaged seals.

Measure the resistance for the OSS sensor circuit, between the transaxle vehicle harness C168a and the PCM transaxle harness C175T, harness using the following chart.

TRANSAXLE VEHICLE HARNESS CHART

Output Shaft Speed Sensor Circuit	Transaxle Vehicle Harness	PCM
Output Shaft Speed (OSS) power supply LE111 (VT/GN)	C168a-18	C175T-1
OSS ground RET24 (BN/BU)	C168a-20	C175T-36
OSS sensor signal VET26 (BN/GN)	C168a-19	C175T-25

Is the resistance less than 5 ohms?

Yes : GO to C4 .
No : REPAIR the circuit(s) for an open. CONNECT all components. TEST the system for normal operation.

C4 CHECK THE VEHICLE HARNESS FOR A SHORT TO GROUND

Disconnect: Transaxle Vehicle Harness C168b.

Measure the resistance for the OSS sensor circuit between the transaxle vehicle harness C168a and ground using the following chart.

TRANSAXLE VEHICLE HARNESS CHART

Output Shaft Speed Sensor Circuit	Transaxle Vehicle Harness	Ground
Transmission Range (TR)/OSS power supply LE111 (VT/GN)	C168a-18	Ground
TR /OSS ground RET24 (BN/BU)	C168a-20	Ground
OSS sensor signal VET26 (BN/GN)	C168a-19	Ground

Is the resistance greater than 10,000 ohms?

Yes : GO to C5 .
No : REPAIR the circuit(s) for a short to ground. CONNECT all components. TEST the system for normal operation.

C5 CHECK THE VEHICLE HARNESS FOR A SHORT TO VPWR

Check for voltage between the OSS sensor circuits and the transaxle vehicle harness C168a using the following chart.

TRANSAXLE VEHICLE HARNESS CHART

Output Shaft Speed Sensor Circuit	Transaxle Vehicle Harness	Ground
Transmission Range (TR)/OSS power supply LE111 (VT/GN)	C168a-18	Ground
TR /OSS ground RET24 (BN/BU)	C168a-20	Ground
OSS sensor signal VET26 (BN/GN)	C168a-19	Ground

Is any voltage present?

Yes : REPAIR the circuit(s) for a short to voltage. CONNECT all components. TEST the system for normal operation.
No : GO to C6 .

C6 CHECK THE SOLENOID BODY FOR AN INTERNAL OPEN CIRCUIT
- Remove the main control cover. Refer to MAIN CONTROL COVER .
- Disconnect: TR Sensor.
- Disconnect: OSS Sensor.
- Use a mirror to inspect both ends of the connectors for damage or pushed-out pins, corrosion, loose wires and missing or damaged seals.
- Measure the resistance of the solenoid body internal sensor power circuit between the main solenoid body leadframe connector pin 18, leadframe side and the OSS sensor connector pin 4, leadframe side.
  
  Fig 1: Measuring Resistance Between Main Solenoid Body Leadframe Connector Pin 18 And OSS Sensor Connector Pin 4
  Courtesy of FORD MOTOR CO.
- Measure the resistance of the solenoid body internal sensor signal circuit between the main solenoid body leadframe connector pin 19, leadframe side and the OSS sensor connector pin 3, leadframe side.
  
  Fig 2: Measuring Resistance Between Main Solenoid Body Leadframe Connector Pin 19 And OSS Sensor Connector Pin 3
  Courtesy of FORD MOTOR CO.
- Measure the resistance of the solenoid body internal sensor ground circuit between the main solenoid body leadframe connector pin 20, leadframe side and the OSS sensor connector pin 1, leadframe side.
  
  Fig 3: Measuring Resistance Between Main Solenoid Body Leadframe Connector Pin 20 And OSS Sensor Connector Pin 1
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to C7 .
- No : INSTALL a new solenoid body leadframe. REFER to SOLENOID BODY LEADFRAME . CONNECT all components. TEST the system for normal operation.
C7 CHECK FOR VOLTAGE AND GROUND AT THE OSS SENSOR CONNECTOR
- Connect: PCM C175T.
- Connect: Transaxle Vehicle Harness C168a.
- Ignition ON.
- Measure the voltage on the solenoid body leadframe between OSS sensor connector pins 1 and 4.
  
  Fig 4: Measuring Voltage Between OSS Sensor Connector Pins 1 And 4
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : INSTALL a new speed sensor. REFER to OUTPUT SHAFT SPEED (OSS) SENSOR . TEST the system for normal operation. If the condition is still present, INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS - 2.5L or ELECTRONIC ENGINE CONTROLS - 3.0L (4V) .
- No : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS - 2.5L or ELECTRONIC ENGINE CONTROLS - 3.0L (4V) . CONNECT all components. TEST the system for normal operation.