Nissan Sentra B18 (2020-2025) Service Manual: Primary Speed Sensor Circuit

Diagnosis Procedure

1. CHECK HARNESS CONNECTOR - 1

   1. Ignition switch OFF.

   2. Check the mating condition of TCM harness connector and primary speed sensor harness connector.

   Is the inspection result normal?

   YES >>

   GO TO 2.

   NO >>

   Repair or replace damaged parts.

2. CHECK CONNECTOR TERMINAL - 1

   1. Disconnect TCM harness connector and primary speed sensor harness connector.

   2. Check the connectors of TCM and primary speed sensor for water intrusion, or damage or corrosion of the terminals.

   Is the inspection result normal?

   YES >>

   GO TO 3.

   NO >>

   Repair or replace damaged parts.

3. CHECK DETECTED DTC

   Are secondary speed sensor malfunction detected in addition to primary speed sensor?

   YES >>

   GO TO 4.

   NO >>

   GO TO 10.

4. CHECK SENSOR GROUND CIRCUIT - 1

   1. Connect TCM harness connector.

   2. Check continuity (resistance) between primary speed sensor harness connector terminal and ground.

      Primary speed sensor		—	Continuity (Resistance)
      Connector	Terminal
      F55	2	Ground	Existed (1 Ω or less)

   Is the inspection result normal?

   YES >>

   GO TO 6.

   NO >>

   GO TO 5.

5. CHECK SENSOR GROUND CIRCUIT - 2

   1. Disconnect TCM harness connector.

   2. Check continuity (resistance) between TCM harness connector terminal and primary speed sensor harness connector terminal.

      TCM		Primary speed sensor		Continuity (Resistance)
      Connector	Terminal	Connector	Terminal
      F23	11	F55	2	Existed (1 Ω or less)

   Is the inspection result normal?

   YES >>

   GO TO 6.

   NO >>

   Repair harness or connector.

6. CHECK SENSOR POWER SUPPLY CIRCUIT - 1

   1. Connect TCM harness connector.

   2. Ignition switch ON.

   3. Check voltage between primary speed sensor harness connector terminal and ground.

      +		−	Voltage (Approx.)
      Primary speed sensor
      Connector	Terminal
      F55	3	Ground	5 V

   Is the inspection result normal?

   YES >>

   GO TO 10.

   NO >>

   GO TO 7.

7. CHECK SENSOR POWER SUPPLY CIRCUIT - 2

   1. Ignition switch OFF.

   2. Disconnect TCM harness connector.

   3. Check continuity (resistance) between TCM harness connector terminal and primary speed sensor harness connector terminal.

      TCM		Primary speed sensor		Continuity (Resistance)
      Connector	Terminal	Connector	Terminal
      F23	36	F55	3	Existed (1 Ω or less)

   Is the inspection result normal?

   YES >>

   GO TO 8.

   NO >>

   Repair harness or connector.

8. CHECK SENSOR POWER SUPPLY CIRCUIT - 3

   1. Ignition switch ON.

   2. Check voltage between TCM harness connector terminal and ground.

      +		−	Voltage (Approx.)
      TCM
      Connector	Terminal
      F23	36	Ground	0 V

   Is the inspection result normal?

   YES >>

   GO TO 9.

   NO >>

   Repair harness.

9. CHECK TCM POWER SUPPLY AND GROUND CIRCUITS

   Check TCM power supply and ground circuits. Refer to Diagnosis Procedure.

   Is the inspection result normal?

   YES >>

   INSPECTION END

   NO >>

   Repair or replace damaged parts.

10. CHECK PRIMARY SPEED SENSOR SIGNAL CIRCUIT

    Check continuity (resistance) between TCM harness connector terminal and primary speed sensor harness connector terminal.

    TCM		Primary speed sensor		Continuity (Resistance)
    Connector	Terminal	Connector	Terminal
    F23	35	F55	1	Existed (1 Ω or less)

    Is the inspection result normal?

    YES >>

    GO TO 11.

    NO >>

    Repair harness or connector.

11. CHECK TCM INPUT SIGNAL (PRIMARY SPEED SENSOR SIGNAL)

    1. Connect TCM harness connector and primary speed sensor harness connector.

    2. Start the engine.

    3. Check frequency between TCM harness connector terminal and ground.

       TCM		—	Test condition	Frequency
       Connector	Terminal
       F23	35	Ground	Accelerator pedal position: 0.5/8 Shift position: “L” position Nissan Sentra Vehicle speed: 20 km/h (12 MPH)	1050 Hz

    Is the inspection result normal?

    YES >>

    INSPECTION END

    NO >>

    Replace primary speed sensor. Refer to Removal and Installation.

© 2014-2026 Copyright www.nisentra.com