P0720
DTC P0720 or P0722
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P0720
- Output Speed Sensor Circuit Performance
DTC P0722
- Output Speed Sensor Circuit No Signal
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The output shaft speed (OSS) sensor is a hall-effect type sensor. The sensor faces the output shaft machined teeth surface. As the output shaft rotates, the sensor produces a signal frequency based on the machined surface of the output shaft. This signal is transmitted to the Transmission Control Module (TCM). The TCM uses the OSS signal in connection with the input speed sensor signal to control engine torque, shift timing, and lock-up.
Conditions for Running the DTC
P0720
* The ignition voltage is 10.2-15.5 V.
* The engine speed is greater than 400 RPM for 2 s.
* The transmission is not in emergency mode.
* Driving in drive (D) range.
* TCM communication is normal.
* Vehicle speed by ABS is greater than 30 km/h (19 MPH).
P0722
* The ignition voltage is 10.2-15.5 V.
* The engine speed is greater than 400 RPM for 2 s.
* The transmission is not in emergency mode.
* TCM communication is normal.
* Driving in D range.
Conditions for Setting the DTC
P0720
Deviation from calculated output speed is more than 15% for 1 s over 10 times.
P0722
* Deviation from calculated output speed is more than 300 RPM.
* No output speed sensor pulse while receiving pulses on the input speed sensor.
* No output speed sensor pulse when vehicle speed from ABS is more than 20 km/h (12 MPH) for 300 ms.
Action Taken When the DTC Sets
* DTCs P0720 and P0722 are Type A DTCs.
* The TCM freezes transmission adaptive functions.
* The TCM turns OFF all solenoids.
* The TCM allows the vehicle after a stop to operate only in the second gear and reverse (R) range.
Conditions for Clearing the DTC
* DTCs P0720 and P0722 are Type A DTCs.
* Output speed is greater than 300 RPM for more than 70 s.
* Deviation from calculated output speed is less than 5% for more than 1 s.
Diagnostic Aids
* Damage or misalignment of the counter drive gear machined teeth surface may cause a speed sensor malfunction.
* Proper torque of the OSS mounting bolt is critical to proper OSS operation.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics AF40-6 (MDK) - Automatic Transmission
Connector End View Reference
Component Connector End Views Sunshade - Left
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Description and Operation
Transmission Component and System Description Transmission Component and System Description
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Operate the vehicle at 16-32 km/h (10-20 MPH) while observing the scan tool Transmission OSS parameter.
2. Verify the Transmission OSS parameter should vary with the vehicle speed and not drop out.
• If the OSS parameter does not change with the vehicle speed
Refer to Circuit/System Testing
• If the OSS parameter changes with the vehicle speed
3. Operate the vehicle within the Conditions for Running the DTC. It may be helpful to operate the vehicle within the conditions identified from the Freeze Frame/Failure Records data.
4. Verify the DTC do not set.
• If the DTC is set
Refer to Circuit/System Testing
• If the DTC is not set
5. All OK.
Circuit/System Testing
Note: Circuit/System Verification must be performed before proceeding with Circuit/System Testing.
1. Ignition OFF, and all vehicle systems OFF. Remove the K71 Transmission Control Module to disconnect the X2 harness connector. It may take up to 2 min for all vehicle systems to power down.
2. Test for infinite resistance between ground and the terminals listed below:
* Signal circuit terminal 19 at the X2 harness connector
* Signal circuit terminal 20 at the X2 harness connector
• If less than infinite resistance
1. Test for infinite resistance between the appropriate signal circuit and each terminal at the X2 harness connector.
• If less than infinite resistance, replace the wiring harness.
• If infinite resistance
2. Connect the positive lead of the DMM to the terminal 19 and the negative lead to the terminal 20 at the X2 harness connector.
3. Test for 4.5-5 Mohms.
• If not within 4.5-5 Mohms , replace the T12 Automatic Transmission Assembly
• If infinite resistance
3. Verify the DTC does not set while operating the vehicle under the Conditions for Running the DTC.
• If the DTC is set
Replace the K71 Transmission Control Module.
• If the DTC is not set
4. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Automatic transmission replacement, refer to Transmission Replacement Transmission Replacement.
* Wiring harness replacement, refer to Automatic Transmission Wiring Harness Replacement Service and Repair.
* Refer to Control Module References Control Module References for TCM replacement, programming and setup.
* Perform the Transmission Adaptive Functions Transmission Adaptive Functions.