Pinpoint Test L : DTCS P0720, P0721, P0722
WARNING: This page is about a different variant/trim than selected.
- Refer to Transmission Controls - 6F15
for schematic and connector information.
Normal Operation and Fault Conditions
The OSS sensor is a Hall-effect sensor that sends a signal to the PCM that indicates transmission output shaft speed. The OSS sensor is used for TCC control and shift scheduling.
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition PCM P0720:00 Output Shaft Speed Sensor Circuit: No Sub Type Information P0720 sets when output speed signal failed to 0 speed and vehicle conditions (mainly turbine speed) indicate OSS output should be present. Electrical failures (open, short) of the OSS wiring or a failure of the sensor itself will cause this failure. Hydraulic / Mechanical failure of the transmission that results in excessive slip in Reverse or 1st gear may also cause P0720 to set. Verify transmission function before starting this pinpoint test. PCM P0721:00 Output Shaft Speed Sensor Circuit Range/Performance: No Sub Type Information Unrealistic change in the OSS sensor signal, erratic or intermittently no input. PCM P0722:00 Output Shaft Speed Sensor Circuit No Signal: No Sub Type Information No input from the OSS sensor. Possible Sources
- Connectors damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals
- OSS sensor
- PCM
- Excessive transmission slippage (no vehicle movement in Drive and/or Reverse).
- L1 RETRIEVE AND RECORD ALL DTCS
- Using the diagnostic scan tool, retrieve all DTCs.
Are DTCs P0720, P0721, P0722 and/or P0715, present?
Yes GO to L2 No REFER to: Diagnosis By Symptom . - L2 CHECK THE OSS (OUTPUT SHAFT SPEED) SENSOR VEHICLE POWER CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect Transmission Harness C1520A.
- 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 C1520A-18 Ground
Is the voltage greater than 11 volts?
Yes GO to L3 No REPAIR the open circuit, if an open circuit is not found, Refer to PCM Guided Routine Testing . CARRY OUT the Transmission Strategy Download, REFER to: Transmission Strategy Download . - L3 CHECK THE OSS (OUTPUT SHAFT SPEED) SENSOR GROUND CIRCUIT
- Ignition ON.
Is the voltage greater than 11 volts?
Yes GO to L4 No REPAIR the circuit. - L4 CHECK THE OSS (OUTPUT SHAFT SPEED) SENSOR SIGNAL CIRCUIT FOR AN OPEN
- Ignition ON.
Is the voltage greater than 4.5 volts?
Yes GO to L5 No INSPECT and REPAIR the circuit. If an open circuit is not found, Refer to PCM Guided Routine Testing . CARRY OUT the Transmission Strategy Download, REFER to: Transmission Strategy Download . - L5 CHECK THE OSS (OUTPUT SHAFT SPEED) SENSOR CIRCUITS IN THE TRANSMISSION INTERNAL WIRING HARNESS FRAME FOR AN OPEN
- Remove the main control cover. REFER to: Main Control Cover .
- Disconnect OSS Sensor.
- Inspect the connector for damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals.
- Measure:
Positive Lead Measurement / Action Negative Lead Transmission, component side pin 19 OSS sensor internal harness, pin 3 Transmission, component side pin 18 OSS sensor internal harness, pin 4 Transmission, component side pin 20 OSS sensor internal harness, pin 1
Are the resistances less than 3 ohms?
Yes GO to L6 No INSTALL a new transmission internal wiring harness frame. REFER to: Transmission Internal Wiring Harness Frame . - L6 CHECK THE OSS (OUTPUT SHAFT SPEED) SENSOR CIRCUITS IN THE TRANSMISSION INTERNAL WIRING HARNESS FRAME FOR A SHORT TO GROUND
- Measure:
Positive Lead Measurement / Action Negative Lead Transmission, component side pin 19 Ground Transmission, component side pin 18 Ground Transmission, component side pin 20 Ground
Are the resistances greater than 10, 000 ohms?
Yes INSTALL a new OSS sensor. REFER to: Output Shaft Speed (OSS) Sensor . No INSTALL a new transmission internal wiring harness frame. REFER to: Transmission Internal Wiring Harness Frame . - Measure: