Code No. P0720: Output Shaft Speed Sensor System


DIAGNOSIS CODE SET CONDITIONS


When the vehicle speed changes by - 20 km/h or more in 0.05 seconds while driving at 20 km/h or more.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. Check the A/T-ECU terminal voltage and frequency.
[A/T-ECU connector (harness side, connected)]
Check that the voltage between PGB- terminal and GND1 or GND2 terminal is 0 V, and then check the frequency of PGB1 terminal.

  • At D range, vehicle speed is 30 km/h : Approx. 588 Hz

Q. Is the check result normal?
Go to Step 6.
Go to Step 2.

STEP 2. Check the power supply and sensor earth.
[output shaft speed sensor connector (harness side, disconnected)]

  • With the ignition switch ON: Power supply terminal to earth terminal → System voltage

Q. Is the check result normal?
Go to Step 3.
Go to Step 4.

STEP 3. Check for continuity in PGB1 line between the input shaft speed sensor connector and A/T-ECU connector.
When the continuity check result is OK, check that the wiring harness is not shorted to the body and other wiring harness.

Q. Is the check result normal?
Replace the output shaft speed sensor with the one of the same transmission of the same model. Then go to Step 7.
Repair the connector(s) or wiring harness, and then go to Step 6.

STEP 4. Check the path between the battery and the output shaft speed sensor.

  • Check the power supply line for an open/short circuit between the battery and output shaft speed sensor connector.
  • Check for a blown fuse.

Q. Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.

STEP 5. Check for continuity in PGB- line between the input shaft speed sensor connector and A/T-ECU connector.
When the continuity check result is OK, check that the wiring harness is not shorted to the body and other wiring harness.

Q. Is the check result normal?
Go to Step 8.
Repair the connector(s) or wiring harness.

STEP 6. Drive the vehicle for a while.
Check that the normal code is displayed.

Q. Is the check result normal?
The procedure is complete.
Replace the A/T-ECU.

STEP 7. After replacing the output shaft speed sensor, drive the vehicle for a while, and then check the diagnosis code again.

Q. Is the check result normal?
Replace the output shaft speed sensor.
Replace the A/T-ECU. Than go to Step 9.

STEP 8. Check the A/T-ECU connector pin terminal and the connection status.

Q. Is there a failure point?
Repair or replace the failure section.
Replace the A/T-ECU.

STEP 9. Diagnosis code recheck.

  1. Erase the diagnosis code.
  2. Drive the vehicle at 20 km/h or more.
  3. Check if the diagnosis code is set.

Q. Is the diagnosis code set?
Remove the A/T. Carry out the internal check and repair the defective part (the output shaft speed sensor rotor may be defective).
The procedure is complete.