Infiniti F50. Manual - part 236

ELECTRONIC KEY SYSTEM

BL-191

C

D

E

F

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M

A

B

BL

Terminals and Reference Value for Steering Lock Control Unit

EIS003QI

Terminals and Reference Value for NATS IMMU

EIS003QJ

TERMINAL 

WIRE 

COLOR

ITEM

CONDITION

VOLTAGE

1

Y/G

Battery power supply

—

Battery voltage

2

PU/W

Key switch

Key inserted (ON) 

→

 Key removed from 

IGN key cylinder (OFF)

Battery voltage 

→

 0V

3

L

NATS IMMU

Key inserted (key switch OFF 

→

 ON)

Just after inserting electronic key to 
key cylinder: Point of tester should 
move

4

B

Ground

—

0V

TERMINAL 

WIRE 

COLOR

ITEM

CONDITION

VOLTAGE

1

W

Battery power supply

—

Battery voltage

2

PU/W

Key switch

Key inserted (ON) 

→

 Key removed from 

IGN key cylinder (OFF)

Battery voltage 

→

 0V

3

W/B

Ignition switch

Ignition switch ON or START position

Battery voltage

5

R

NATS antenna amp.

key inserted (key switch OFF 

→

 ON)

0V 

→

 Approx. 5V (for 3 seconds)

6

Y

NATS antenna amp.

Key inserted (key switch OFF 

→

 ON)

Just after inserting electronic key to 
key cylinder: Point of tester should 
move

7

Y/G

NATS antenna amp.

Key inserted (key switch OFF 

→

 ON)

Just after inserting electronic key to 
key cylinder: Point of tester should 
move

8

B/R

NATS antenna amp.

—

0V

9

B/W

Ground

—

0V

10

L

Steering lock control unit

Key inserted (key switch OFF 

→

 ON)

Just after inserting electronic key to 
key cylinder: Point of tester should 
move

11

G/W

ECM

—

—

15

G

Security indicator lamp

Goes OFF 

→

 illuminates (every 2.4 sec-

onds)

Battery voltage 

→

 0V

BL-192

ELECTRONIC KEY SYSTEM

Work Flow

EIS000O7

PIIA2862E

ELECTRONIC KEY SYSTEM

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Diagnostic System Diagram

EIS000O8

Symptom Chart 

EIS0012T

SYMPTOM 1: ELECTRONIC KEY DOES NOT TURN

*: If the ignition key cylinder cannot be turned by the emergency key, the ignition key cylinder is malfunctioning.

SYMPTOM 2: SECURITY INDICATOR DOES NOT FLASH

PIIA0378E

Symptom

Diagnostic Procedure

Possible malfunctioning 

part or status

Reference part in the 

trouble diagnostic 

system diagram

Reference 

page

Security indicator remains 
flashing with Electronic key 
inserted.

Diagnostic Procedure 1

Key switch

C5

BL-194

Security indicator turns OFF 
with Electronic key inserted.

Diagnostic Procedure 2

NATS IMMU

A

BL-195

Steering lock control unit

F

Harness system

C7

Ignition key cylinder*

—

—

Checking with the emergency 
key

Symptom

Diagnostic Procedure

Possible malfunctioning 

part or status

Reference part in the 

trouble diagnostic 

system diagram

Reference 

page

Security indicator does not turn 
ON.

Diagnostic Procedure 3

Security indicator

—

BL-196

Open circuit in the bat-
tery power supply line to 
the security indicator

—

NATS IMMU

A

Harness system

C6

BL-194

ELECTRONIC KEY SYSTEM

Diagnostic Procedure 1

EIS0012U

1. 

CHECK ELECTRONIC KEY INSERT SIGNAL

Check voltage between NATS IMMU connector M32 terminal 2 (PU/
W) and ground.

OK or NG

OK

>> Replace NATS IMMU.

NG

>> GO TO 2.

2. 

CHECK KEY SWITCH CIRCUIT

1.

Remove the key from the ignition key cylinder.

2.

Disconnect NATS IMMU and key switch and key lock solenoid (key switch) connector.

3.

Check continuity between NATS IMMU connector M32 terminal 2 (PU/W) and key switch and key lock
solenoid (key switch) connector M64 terminal 4 (PU/W).

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace harness.

3. 

CHECK KEY SWITCH

Check continuity key switch terminals.

OK or NG

OK

>> Check the following.

●

10A fuse [No. 8, located in fuse block (J/B) No.1]

●

Harness for open or short between key switch and
fuse

NG

>> Replace key switch.

Terminals

Condition

Voltage

2 (PU/W) 

−

 ground

Electronic key removed from 
ignition key cylinder

0V

Electronic key inserted in 
ignition cylinder

Battery voltage

PIIA3124E

Continuity should exist.

PIIA3138E

Terminal

Condition of key switch

Continuity

3 – 4

Key is inserted.

Yes

Key is removed.

No

PIIA3044E