Key Switch (Intelligent Key Unit Input) Check

2009 Nissan-Datsun Sentra L4-2.0L (MR20DE)SECTION Key Switch (Intelligent Key Unit Input) Check




INTELLIGENT KEY SYSTEM


Key Switch (Intelligent Key Unit Input) Check

1. CHECK KEY SWITCH
With CONSULT-III
Check key switch ("KEY SW") in "DATA MONITOR" mode with CONSULT-III.





Without CONSULT-III
1. Turn ignition switch OFF.
2. Disconnect Intelligent Key unit harness connector.





3. Check voltage between Intelligent Key unit harness connector
M42 terminal 7 and ground.





OK or NG
OK >> Key switch is OK.
NG >> GO TO 2.
2. CHECK KEY SWITCH POWER SUPPLY CIRCUIT
1. Remove mechanical key from ignition switch.
2. Disconnect key switch and ignition knob switch connector.
3. Check voltage between key switch and ignition knob switch harness connector M49 terminal 2 and ground.






2 - Ground : Battery voltage

OK or NG
OK >> GO TO 3.
NG >> Repair or replace key switch and ignition knob switch power supply circuit.
3. CHECK KEY SWITCH OPERATION





Check continuity between key switch and ignition knob switch terminals 1 and 2.





OK or NG
OK >> GO TO 4.
NG >> Replace key cylinder assembly (built-in key switch).
4. CHECK KEY SWITCH CIRCUIT
1. Check continuity between Intelligent Key unit harness connector M42 (A) terminal 7 and key switch and ignition knob switch harness connector M49 (B) terminal 1.






7 - 1 : Continuity should exist.

2. Check continuity between Intelligent Key unit harness connector M42 (A) terminal 7 and ground.

7 - Ground : Continuity should not exist.

OK or NG
OK >> Check the condition of harness and harness connector.
NG >> Repair or replace harness between Intelligent Key unit and key switch and ignition knob switch.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.