Code No. P0720: Malfunction of Secondary Pulley Speed Sensor














DIAGNOSTIC FUNCTION



JUDGMENT CRITERIA



  • The status with the primary pulley speed of 1,000 r/min or more and with the secondary pulley speed of 150 r/min or less continues for five seconds.
  • 0.1 seconds after the vehicle speed computed by CVT has dropped abruptly from 20 km/h or more to 5 km/h or less
  • When the secondary pulley speed sensor is found abnormal by comparing the engine speed, primary pulley speed, and vehicle speed

PROBABLE CAUSES



  • Malfunction of secondary pulley speed sensor
  • Damaged wiring harness and connectors
  • Malfunction of CVT-ECU

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III data list
Item 02: Secondary speed sensor signal (Refer to Service Data Table .)

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

STEP 2. Check the following connector:

  • C-135 CVT-ECU connector
  • B-118 Secondary pulley speed sensor connector
  • A-63 Intermediate connector
Check the terminals for a contact status problem and internal short circuit.

Q. Is the check result normal?
Go to Step 3.
Repair the defective connector.

STEP 3. Check for open circuit in the wiring harness between the secondary pulley speed sensor connector and the CVT-ECU connector.
Between B-118 secondary pulley speed sensor connector (terminal No. 3) and C-135 CVT-ECU connector (terminal No. 48)

Q. Is the check result normal?
Go to Step 4.
Repair the wiring harness.

STEP 4. Check for open circuit and short to earth in the wiring harness between the secondary pulley speed sensor connector and the CVT-ECU connector
Between B-118 secondary pulley speed sensor connector (terminal No. 2) and C-135 CVT-ECU connector (terminal No. 36)

Q. Is the check result normal?
Go to Step 5.
Repair the wiring harness.

STEP 5. Check for open circuit in the wiring harness between the CVT control relay and the secondary pulley speed sensor connector.
Between A-18X CVT control relay (terminal No. 3) and B-118 secondary pulley speed sensor connector (terminal No. 1)

Q. Is the check result normal?
Go to Step 6.
Repair the wiring harness.

STEP 6. Secondary pulley speed sensor check
Visually check the tip of the sensor for foreign materials or damage.

Q. Is the check result normal?
Go to Step 7.
Repair.

STEP 7. Diagnosis code recheck after replacing the secondary pulley speed sensor

Q. Is the check result normal?
The inspection is complete.
Replace CVT-ECU.