Nissan Sentra B18 (2020-2025) Service Manual: Ignition Signal

Component Function Check

1. INSPECTION START

   Turn ignition switch OFF, and restart engine.

   Does the engine start?

   YES-1 >>

   With CONSULT: GO TO 2.

   YES-2 >>

   Without CONSULT: GO TO 3.

   NO >>

   Refer to Diagnosis Procedure.

2. CHECK IGNITION SIGNAL FUNCTION-1

   With CONSULT

   1. Perform “POWER BALANCE” in “ACTIVE TEST” mode of “ENGINE” with CONSULT.

   2. Check that each circuit produces a momentary engine speed drop.

   Is the inspection result normal?

   YES >>

   INSPECTION END

   NO >>

   Refer to Diagnosis Procedure.

3. CHECK IGNITION SIGNAL FUNCTION-2

   Without CONSULT

   1. Let engine idle.

   2. Read the voltage signal between ECM harness connector terminals with an oscilloscope.

      ECM				Voltage signal
      +		−
      Connector	Terminal	Connector	Terminal
      F25	109	E16	162
      	106
      	105
      	103

      Note:

      The pulse cycle changes depending on rpm at idle.

   Is the inspection result normal?

   YES >>

   INSPECTION END

   NO >>

   Refer to Diagnosis Procedure.

Diagnosis Procedure

1. CHECK IGNITION COIL POWER SUPPLY

   1. Turn ignition switch OFF.

   2. Disconnect ignition coil harness connector.

   3. Turn ignition switch ON.

   4. Check the voltage between ignition coil harness connector and ground.

      +			−	Voltage
      Ignition coil
      Cylinder	Connector	Terminal
      1	F34	3	Ground	Battery voltage
      2	F35	3
      3	F36	3
      4	F37	3

   Is the inspection result normal?

   YES >>

   GO TO 5.

   NO >>

   GO TO 2.

2. CHECK FUSE

   1. Turn ignition switch OFF.

   2. Pull out No. 80fuse (15 A) and check that the fuse is not blowing.

   Is the inspection result normal?

   YES >>

   GO TO 3.

   NO >>

   Replace the fuse after repairing the applicable circuit.

3. CHECK IGNITION COIL POWER SUPPLY CIRCUIT

   1. Turn ignition switch OFF.

   2. Disconnect IPDM E/R harness connector.

   3. Check the continuity between IPDM E/R harness connector and condenser harness connector.

      IPDM E/R		Condenser		Continuity
      Connector	Terminal	Connector	Terminal
      F96	66	F8	1	Existed

   4. Check harness for short to ground and to power.

   Is the inspection result normal?

   YES >>

   GO TO 4.

   NO >>

   Repair or replace error-detected parts.

4. CHECK IPDM E/R POWER SUPPLY AND GROUND CIRCUIT

   Check IPDM E/R power supply and ground circuit. Refer to Diagnosis Procedure(with I-key) Refer to Diagnosis Procedure(with out I-key). Diagnosis Procedure.

   Is the inspection result normal?

   YES >>

   Replace IPDM E/R. Refer to Removal and Installation(with I-key) Refer to Removal and Installation(with out I-key).

   NO >>

   Repair or replace error-detected parts.

5. CHECK IGNITION COIL GROUND

   1. Turn ignition switch OFF.

   2. Check the continuity between ignition coil harness connector and ground.

      +			−	Continuity
      Ignition coil
      Cylinder	Connector	Terminal
      1	F34	2	Ground	Existed
      2	F35	2
      3	F36	2
      4	F37	2

   Is the inspection result normal?

   YES >>

   GO TO 6.

   NO >>

   Repair or replace error-detected parts.

6. CHECK IGNITION SIGNAL CIRCUIT

   1. Disconnect ECM harness connector.

   2. Check the continuity between ignition coil harness connector and ECM harness connector.

      Ignition coil			ECM		Continuity
      Cylinder	Connector	Terminal	Connector	Terminal
      1	F34	1	F25	109	Existed
      2	F35	1		106
      3	F36	1		105
      4	F37	1		103

   3. Also check harness for short to ground and to power.

   Is the inspection result normal?

   YES >>

   GO TO 7.

   NO >>

   Repair or replace error-detected parts.

7. CHECK IGNITION COIL WITH POWER TRANSISTOR

   Check ignition coil with power transistor. Refer to Component Inspection.

   Is the inspection result normal?

   YES >>

   INSPECTION END

   NO >>

   Replace malfunctioning ignition coil with power transistor. Refer to Removal and Installation.

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