LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Nissan-Datsun >> 2012 >> Sentra Base, Standard Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Component Testing (MR20DE) (CALIFORNIA) >> Ignition Signal >> Diagnosis Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis Procedure

  1. CHECK ENGINE START

    Turn ignition switch OFF, and restart engine.

    Is engine running? 

    YES ( With CONSULT) >> GO TO 2.

    YES ( Without CONSULT) >> GO TO  3.

    NO: GO TO  4.

  2. CHECK OVERALL FUNCTION

    With CONSULT

    1. Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT.
    2. Make sure that each circuit produces a momentary engine speed drop.

    OK or NG 

    OK: INSPECTION END 

    NG: GO TO  10.

  3. CHECK OVERALL FUNCTION

    Without CONSULT

    1. Let engine idle.
    2. Read the voltage signal between ECM terminals 17, 18, 21, 22 and ground with an oscilloscope.
    3. Verify that the oscilloscope screen shows the signal wave as shown in the figure.
    NOTE: The pulse cycle changes depending on rpm at idle.
    Fig 1: Signal Waveform Graph (Signal Between ECM Terminals 17, 18, 21, 22 And Ground)
    G04925642Courtesy of NISSAN NORTH AMERICA, INC.
    Fig 2: Checking Overall Function
    G04925643Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: INSPECTION END 

    NG: GO TO  10.

  4. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-I
    1. Turn ignition switch OFF, wait at least 10 seconds and then turn ON.
    2. Check voltage between ECM terminal 105 and ground with CONSULT or tester.

    Voltage: Battery voltage 

    Fig 3: Checking Ignition Coil Power Supply Circuit-I
    G04925644Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO 5.

    NG: Go to POWER SUPPLY AND GROUND CIRCUIT .

  5. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-II
    1. Turn ignition switch OFF.
    2. Disconnect condenser-2 (1) harness connector.
    3. Turn ignition switch ON.
      Fig 4: Identifying Condenser-2 Harness Connector
      G04925645Courtesy of NISSAN NORTH AMERICA, INC.
    4. Check voltage between condenser-2 terminal 1 and ground with CONSULT or tester.

    Voltage: Battery voltage 

    Fig 5: Checking Ignition Coil Power Supply Circuit-II
    G04875485Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO  8.

    NG: GO TO 6.

  6. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-III
    1. Turn ignition switch OFF.
    2. Disconnect IPDM E/R harness connector E43.
    3. Check harness continuity between IPDM E/R terminal 3 and condenser-2 terminal 1.

      Refer to Wiring Diagram .

      Continuity should exist  .

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

    OK or NG 

    OK: Go to POWER SUPPLY AND GROUND CIRCUIT .

    NG: GO TO 7.

  7. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors E17, F10
    • Harness for open or short between IPDM E/R and condenser-2

    Repair open circuit or short to ground or short to power in harness or connectors.

  8. CHECK CONDENSER-2 GROUND CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Check harness continuity between condenser-2 terminal 2 and ground.

      Refer to Wiring Diagram .

      Continuity should exist  .

    3. Also check harness for short to power.

    OK or NG 

    OK: GO TO 9.

    NG: Repair open circuit or short to power in harness or connectors.

  9. CHECK CONDENSER-2

    Refer to "COMPONENT INSPECTION "

    OK or NG 

    OK: GO TO 10.

    NG: Replace condenser-2.

  10. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-IV
    1. Turn ignition switch OFF.
    2. Reconnect all harness connectors disconnected.
    3. Disconnect ignition coil (1) harness connector.
    4. Turn ignition switch ON.
      Fig 6: Identifying Ignition Coil Connectors
      G04925637Courtesy of NISSAN NORTH AMERICA, INC.
    5. Check voltage between ignition coil terminal 3 and ground with CONSULT or tester.

    Voltage: Battery voltage 

    Fig 7: Checking Ignition Coil Power Supply Circuit-IV
    G04875257Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO  12.

    NG: GO TO 11.

  11. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connector F10
    • Harness for open or short between ignition coil and harness connector F10

    Repair or replace harness or connectors.

  12. CHECK IGNITION COIL GROUND CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Check harness continuity between ignition coil terminal 2 and ground.

      Refer to Wiring Diagram .

      Continuity should exist  .

    3. Also check harness for short to power.

    OK or NG 

    OK: GO TO 13.

    NG: Repair open circuit or short to power in harness or connectors.

  13. CHECK IGNITION COIL OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminals 17, 18, 21, 22 and ignition coil terminal 1.

      Refer to Wiring Diagram .

      Continuity should exist  .

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

    OK or NG 

    OK: GO TO 14.

    NG: Repair open circuit or short to ground or short to power in harness or connectors.

  14. CHECK IGNITION COIL WITH POWER TRANSISTOR

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 15.

    NG: Replace ignition coil with power transistor. Refer to , "COMPONENT ".

  15. CHECK INTERMITTENT INCIDENT

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    INSPECTION END 

scientia non olet · About LEMON Manuals