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.
[C-137 A/T-ECU connector (vehicle side, connected)]
Check that the voltage between C-137 terminal No. 48 and C-138 terminal No. 13 or C-138 terminal No. 26 is 0 V, and then check the frequency of C-137 terminal No. 37.

  • 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.
[B-130 output shaft speed sensor connector (vehicle side, disconnected)]

  • With the ignition switch ON: Terminal No. 1 to No. 3 → System voltage

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

STEP 3. Check the wiring harness between the output shaft speed sensor and A/T-ECU.
Check for continuity between B-130 output shaft speed sensor terminals and C-137 A/T-ECU terminals.

  • Between B-130 terminal No. 2 and C-137 terminal No. 37: Continuity exists.
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 or replace the failure section, and then go to Step 6.

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

  • Check the wiring harness for an open/short circuit between the ignition switch and B-130 output shaft speed sensor connector terminal No. 1.
  • Check for a blown fuse.

Q. Is the check result normal?
Go to Step 5.
Repair or replace the failure section.

STEP 5. Check the wiring harness between the output shaft speed sensor and A/T-ECU.
Check for continuity between B-130 output shaft speed sensor terminals and C-137 A/T-ECU terminals.

  • Between B-130 terminal No. 1 and C-137 terminal No. 48: Continuity exists.
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 or replace the failure section.

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.

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.