Infiniti Q45 (FY33). Manual — part 437

SFA936B

SFA937B

Diagnostic Procedure 1 (Vehicle speed sensor)

Code No. 11

Disconnect control unit connector, then
re-connect it securely. Perform self-diag-
nosis to check that proper test results are
obtained.

NG

E

OK

INSPECTION END

CHECK CONTROL UNIT INPUT SIG-
NAL.
1. Use a jack to raise the vehicle.
2. With vehicle operating at extremely low

speeds, measure vehicle speed sensor
input signal voltage between control
unit connector terminals

q

22

and

q

24

.

Voltage:

Varies from 0V to 5V.

NG

E

OK

Replace control unit.

Speedometer is operating properly.

OK

E

NG

Faulty speedometer circuit
(Refer to “Inspection/
Vehicle Speed Sensor Sig-
nal Circuit” of “METER
AND GAUGES” in EL sec-
tion.)

Faulty vehicle speed sensor or vehicle
speed sensor-to-control unit harness

GI

MA

EM

LC

EC

FE

AT

PD

RA

BR

ST

RS

BT

HA

EL

IDX

TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMS

H

H

H

FA-47

SFA938B

Diagnostic Procedure 2 (Steering angle sensor)

SFA939B

SFA940B

SFA941B

SFA942B

Code No. 12, 13

Disconnect control unit connector and
steering angle sensor connector, then re-
connect them securely. Perform self-diag-
nosis to check that proper test results are
obtained.

NG

E

OK

INSPECTION END

CHECK CONTROL UNIT INPUT SIG-
NAL.
1. Turn ignition switch to “ON”.
2. Slowly turn steering wheel at least 90°

to left or right from neutral. Measure
voltage between control unit connector
terminals

q

1

and

q

24

,

q

2

and

q

24

, and

q

20

and

q

24

.

Voltage:

Varies from 0V to 5V.

NG

E

OK

Replace control unit.

CHECK STEERING ANGLE SENSOR
OUTPUT SIGNAL.
1. Turn ignition switch to “ON”.
2. Slowly turn steering wheel at least 90°

to left or right from neutral. Measure
voltage between control unit connector
terminals

q

81

and

q

75

,

q

82

and

q

75

, and

q

83

and

q

75

.

Voltage:

Varies from 0V to 5V.

NG

E

OK

Faulty control unit-to-steer-
ing angle sensor harness

CHECK STEERING ANGLE SENSOR
POWER CIRCUIT.
1. Turn ignition switch to “ON”.
2. Slowly turn steering wheel at least 90°

to left or right from neutral. Measure
voltage between steering angle sensor
connector terminal

q

80

and body ground.

Voltage:

Battery voltage

OK

E

NG

Faulty power circuit.
Replace steering angle
sensor and repair faulty
power circuit. Perform self-
diagnosis again.

CHECK STEERING ANGLE SENSOR
GROUND CIRCUIT.
Check continuity between steering angle
sensor connector terminal

q

75

and body

ground.
Continuity should exist.

NG

E

OK

Replace steering angle
sensor.

Faulty ground harness.

TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMS

H

H

H

H

H

FA-48

SFA936B

Diagnostic Procedure 3 (Stop lamp switch)

SFA943B

Code No. 14

Disconnect control unit connector, then
re-connect it securely. Perform self-diag-
nosis to check that proper test results are
obtained.

NG

E

OK

INSPECTION END

CHECK CONTROL UNIT INPUT SIG-
NAL.
1. Turn ignition switch to “ON”.
2. Measure voltage between control unit

connector terminals

q

11

and

q

24

.

Voltage:

Brake pedal depressed:

Approx. 12V

Brake pedal released:

0V

OK

E

NG

Faulty control unit-to-stop
lamp switch harness.

Check that stop lamps illuminate when
brake pedal is depressed.

NG

E

OK

Faulty control unit or con-
trol unit ground circuit.

Faulty battery-to-stop lamp switch harness
or stop lamp switch

GI

MA

EM

LC

EC

FE

AT

PD

RA

BR

ST

RS

BT

HA

EL

IDX

TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMS

H

H

H

FA-49

SFA944B

Diagnostic Procedure 4 (Vertical G sensor)

SFA945B

SFA005C

SFA006C

SFA947BA

Code No. 22, 23

Disconnect control unit connector and ver-
tical G sensor connector, then re-connect
them securely. Perform self-diagnosis to
check that proper test results are
obtained.

NG

E

OK

INSPECTION END

CHECK CONTROL UNIT VERTICAL G
SENSOR POWER CIRCUIT.
1. Turn ignition switch to “ON”.
2. Measure voltage between control unit

connector terminals

q

3

and

q

7

.

Voltage:

Approx. 5V

OK

E

NG

Faulty control unit or con-
trol unit ground circuit.

CHECK CONTROL UNIT VERTICAL G
SENSOR INPUT SIGNAL.
Measure voltage between control unit con-
nector terminals

q

4

and

q

24

,

q

5

and

q

24

,

and

q

24

.

Voltage:

Approx. 2.5V

NG

E

OK

Replace control unit.

CHECK CONTROL UNIT VERTICAL G
SENSOR INPUT SIGNAL CIRCUIT.
Check continuity between control unit con-
nector terminals

q

4

,

q

5

and

q

24

.

Continuity should not exist.

OK

E

NG

Faulty control unit-to-verti-
cal G sensor harness.

CHECK VERTICAL G SENSOR OUTPUT
SIGNAL.
1. Turn ignition switch to “ON”.
2. Measure voltage between vertical G

sensor connector terminals

q

1

and

q

3

and

q

2

and

q

3

.

Voltage:

q

1

—

q

3

Approx. 5V

q

2

—

q

3

Approx. 2.5V

OK

E

NG

Replace vertical G sensor.

Faulty control unit-to-vertical G sensor
harness.

Note: The front vertical G sensor is installed on the rear of the inner pil-

lar and the rear vertical G sensor is located on the rear of the outer
wheelhouse. To check each vertical G sensor output signal,
remove the vertical G sensor, set it vertical, then measure voltage
between terminals.
Be careful not to drop or bump the vertical G sensor as it is easy
to break. If dropped or bumped, replace with a new one.

TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMS

H

H

H

H

H

FA-50