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DTC P0720: Malfunction of Output Speed Sensor
 
 
 
 
DIAGNOSTIC FUNCTION
The TCM determines whether the system is faulty by monitoring the output speed sensor.
 
 
DESCRIPTIONS OF MONITOR METHODS
  • The status with the secondary pulley speed of 1,500 r/min or more and with the output shaft speed of 150 r/min or less continues for 10 seconds.
  • When the output shaft speed has dropped abruptly from 730 r/min or more to 90 r/min or less, and then it keeps 90 r/min or less for 0.5 second continuously.
 
 
MONITOR EXECUTION
Transmission range: "D", "R" or "L"
 
 
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
  • P0705: Malfunction of transmission range switch
  • P0791: Malfunction of secondary pulley speed sensor
Sensor (The sensor below is determined to be normal)
  • Transmission range switch
  • Secondary pulley speed sensor
 
 
LOGIC FLOW CHARTS [Monitor Sequence-Input Rationality Low (Open/Low revolution)]
 
 
LOGIC FLOW CHARTS (Monitor Sequence-Input Open Circuit)
 
 
DTC SET CONDITIONS
Check Conditions
  • Transmission range switch position: "D", "R" or "L"
  • Voltage of battery: 10 volts or more
  • Voltage of battery: 16.5 volts or less
Judgment Criteria
  • The status with the secondary pulley speed of 1,500 r/min or more and with the output speed of less than 150 r/min continues for 10 seconds.
  • The output speed has dropped abruptly from 730 r/min or more to 90 r/min or less. Then at least 0.5 second have passed with the reduced speed.
 
 
OBD-II DRIVE CYCLE PATTERN
The vehicle is driven for at least 20 seconds with the engine speed at 3,500 r/min or more.
 
 
PROBABLE CAUSES
  • Malfunction of output speed sensor
  • Damaged wiring harness and connectors
  • Malfunction of TCM
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
  • MB991958: Scan Tool (M.U.T.-III Sub Assembly)
    • MB991824: Vehicles Communication Interface (V.C.I.)
    • MB991827: M.U.T.-III USB Cable
    • MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
STEP 1. Check the following connector.
  • Output speed sensor connector
Check the terminals for a contact status problem and internal short circuit.
Is the check result normal?
Go to Step 2.
Repair the faulty connector.
 
STEP 2. Check for open circuit in SGN2 line between the output speed sensor connector and the TCM connector.
Is the check result normal?
Go to Step 3.
Repair the connector(s) or the wiring harness.
 
STEP 3. Voltage measurement at output speed sensor connector (terminal number 1).
(1) Disconnect the output speed sensor connector, and measure at the wiring harness side.
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between the output speed sensor connector (terminal number 1) and body ground.
OK: 10 volts or more
Is the check result normal?
Go to Step 4.
Repair the connector(s) or the wiring harness (power supply line between the output speed sensor connector terminal number 1 and the J/B connector).
 
STEP 4. Check the following connector.
  • TCM connector
Check the terminals for a contact status problem and internal short circuit.
Is the check result normal?
Go to Step 5.
Repair the faulty connector.
 
STEP 5. Check for open circuit or short to ground in OUTS line between the output speed sensor connector and the TCM connector.
Is the check result normal?
Go to Step 6.
Repair the wiring harness.
 
STEP 6. Measure the output wave pattern of the output speed sensor at TCM connector (OUTS terminal).
(1) Connect the output speed sensor connector and TCM connector.
(2) Connect an oscilloscope between TCM connector OUTS terminal and body ground (Refer to ).
(3) Transmission range: "D" range
(4) Drive at a constant speed of approximately 20 km/h (12.4 mph).
(5) Use an oscilloscope, measure the voltage between TCM connector OUTS terminal and body ground.
OK: A wave pattern such as the one shown on (Check Procedure Using an Oscilloscope) should be output, and the maximum value should be 11 volts or more and the minimum value should be 1 volt or less. There should be no noise in the output wave pattern.
Is the check result normal?
Go to Step 7.
Replace the output speed sensor (Refer to GROUP 23B, Transaxle ).
 
STEP 7. Using scan tool (M.U.T.-III), recheck the DTC.
Check again if the DTC is stored.
(1) Erase the DTC.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Carry out a test drive with the OBD-II drive cycle pattern.
(4) Recheck the DTC.
Is DTC P0720 stored?
Replace the TCM (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).