Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSNISSAN-DATSUN2012SENTRA SE-RREPAIR AND DIAGNOSIS (SINGLE PAGE)BODY & FRAMEEXTERIOR BODY PANELSBODY, LOCK & SECURITY SYSTEMSERVICE INFORMATIONINTELLIGENT KEY SYSTEMKEY SWITCH (INTELLIGENT KEY UNIT INPUT) CHECK

2012 Nissan-Datsun Sentra SE-R

Key Switch (Intelligent Key Unit Input) Check

2012 Nissan-Datsun Sentra SE-RSECTION Key Switch (Intelligent Key Unit Input) Check

CHECK KEY SWITCH

With CONSULT

Check key switch ("KEY SW") in "DATA MONITOR" mode with CONSULT.

Monitor item	Condition
KEY SW	Insert mechanical key into ignition switch: ON
KEY SW	Remove mechanical key from ignition switch: OFF

Without CONSULT

Turn ignition switch OFF.
Disconnect Intelligent Key unit harness connector.

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

Connector	Terminals		Condition	Voltage (V) (Approx.)
Connector	(+)	(-)	Condition	Voltage (V) (Approx.)
M42	7	Ground	Insert mechanical key into ignition switch	Battery voltage
M42	7	Ground	Remove mechanical key from ignition switch	0

Fig 1: Checking Key Switch

Courtesy of NISSAN NORTH AMERICA, INC.

OK or NG

OK: Key switch is OK.

NG: GO TO 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
  
  Fig 2: Checking Key Switch Power Supply Circuit
  Courtesy of NISSAN NORTH AMERICA, INC.
  
  OK or NG
  
  OK: GO TO 3.
  
  NG: Repair or replace key switch and ignition knob switch power supply circuit.

CHECK KEY SWITCH OPERATION

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

Component	Terminals		Condition	Continuity
Key switch	1	2	Insert mechanical key into ignition switch.	Yes
Key switch	1	2	Remove mechanical key from ignition switch.	No

Fig 3: Checking Key Switch Operation

Courtesy of NISSAN NORTH AMERICA, INC.

OK or NG

OK: GO TO 4.

NG: Replace key cylinder assembly (built-in key switch).

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 .
  
  Fig 4: Checking Key Switch Circuit
  Courtesy of NISSAN NORTH AMERICA, INC.
  
  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:

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