Infiniti G37 Coupe. Manual - part 1248

DIAGNOSIS SYSTEM (4WAS MAIN CONTROL UNIT)

STC-43

< FUNCTION DIAGNOSIS >

[WITH 4WAS]

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DIAGNOSIS SYSTEM (4WAS MAIN CONTROL UNIT)

CONSULT-III Function [4WAS(MAIN)/RAS/HICAS]

INFOID:0000000001666305

FUNCTION

CONSULT-III can display each diagnostic item using the diagnostic test modes shown below.

SELF-DIAG RESULT MODE

Display Item List

Diagnostic test mode

Function

Self-diagnostic results

• Self-diagnostic results can be read and erased quickly.

Data monitor

• Input/Output data in the 4WAS main control unit can be read.

CAN diagnostic support monitor

• The results of transmit/receive diagnosis of CAN communication can be read.

Active test

• Diagnostic Test Mode in which CONSULT-III drives some actuators apart from the 4WAS main 

control unit and also shifts some parameters in a specified range.

ECU part number

• 4WAS main control unit part number can be read.

Items 

(CONSULT-III screen terms)

Diagnostic item is detected when...

Possible cause

CONTROL UNIT
[ABNORMAL1]
[C1900]

An error is detected inside 4WAS main control unit.

4WAS main control unit error

CONTROL UNIT
[ABNORMAL2]
[C1901]

An error is detected inside 4WAS main control unit.

4WAS main control unit error

MOTOR OUTPUT
[REV CURRENT]
[C1902]

4WAS rear motor current error is detected.
(4WAS rear motor current output direction differs.)

4WAS rear motor error

MOTOR OUTPUT
[NO CURRENT]
[C1903]

4WAS rear motor current error is detected.
(Current is input to 4WAS main control unit if 4WAS main control unit 
output is “OFF”.)

4WAS rear motor error

MOTOR OUTPUT
[OVERCURRENT]
[C1904]

4WAS rear motor current error is detected.
(4WAS rear motor output current is large.)

4WAS rear motor error

CONTROL UNIT
[ABNORMAL3]
[C1905]

An error is detected inside 4WAS main control unit.

4WAS main control unit error

CONTROL UNIT
[ABNORMAL5]
[C1906]

An error is detected inside 4WAS main control unit.

4WAS main control unit error

CONTROL UNIT
[ABNORMAL4]
[C1907]

An error is detected inside 4WAS main control unit.

4WAS main control unit error

CONTROL UNIT
[ABNORMAL7]
[C1908]

An error is detected inside 4WAS main control unit.

4WAS main control unit error

CONTROL UNIT
[ABNORMAL6]
[C1909]

An error is detected inside 4WAS main control unit.

4WAS main control unit

MOTOR OUTPUT
[MOTOR LOCK]
[C1910]

Inside 4WAS rear motor error is detected.
(4WAS main motor does not move or the rear wheel angle sensor 
value does not change if 4WAS main control unit output is 14A or 
more.)

4WAS rear motor error

STC-44

< FUNCTION DIAGNOSIS >

[WITH 4WAS]

DIAGNOSIS SYSTEM (4WAS MAIN CONTROL UNIT)

MOTOR VOLTAGE
[LOW VOLTAGE]
[C1911]

4WAS rear motor voltage error is detected.
(4WAS rear motor voltage is low.)

4WAS rear motor power supply 
error

MOTOR VOLTAGE
[BAD OBSTRCT]
[C1912]

4WAS rear motor voltage error is detected.
(Voltage is applied to 4WAS main motor if 4WAS main control unit 
output is “OFF”.)

4WAS rear motor power supply 
error

MOTOR OUTPUT
[ABNORML SIG]
[C1913]

4WAS rear motor current error is detected.
(4WAS main motor does not move or the rear wheel angle sensor 
output does not change when 4WAS main control unit output is 18A 
or more and 4WAS main motor output is low.)

4WAS rear motor error

RR ST ANGLE SENSOR
[ABNORML VOL]
[C1914]

The rear wheel angle sensor power supply error is detected.

Rear wheel steering sensor 
power supply error

RR ST ANGLE SENSOR
[MAIN SIGNAL]
[C1915]

The rear wheel angle sensor signal (main) output voltage value error 
is detected.

Rear wheel steering sensor out-
put voltage error

RR ST ANGLE SENSOR
[SUB SIGNAL]
[C1916]

The rear wheel angle sensor signal (sub) output voltage value error 
is detected.

Rear wheel steering sensor out-
put voltage error

RR ST ANGLE SENSOR
[OFFSET SIG1]
[C1917]

The rear wheel angle sensor signal (main and sub) error is detected.
(The output signal value differs temporarily between main and sub.)

Rear wheel steering sensor 
(main and sub) output signal val-
ue error signal

RR ST ANGLE SENSOR
[OFFSET SIG2]
[C1918]

The rear wheel angle sensor signal (main and sub) error is detected.
(The output signal value differs between main and sub.)

Rear wheel steering sensor 
(main and sub) output signal er-
ror

VEHICLE SPEED SEN
[NO SIGNAL]
[C1919]

Malfunction is detected in vehicle speed signal that is output from 
ABS actuator and electric unit (control unit) via CAN communication.
(Improper signal is input while driving.)

Vehicle speed signal error

STEERING ANGLE SEN
[NO SIGNAL]
[C1920]

Malfunction is detected in steering angle sensor signal that is output 
from steering angle sensor via CAN communication.
(No transmission from the steering angle sensor)

Steering angle sensor input sig-
nal error

ENG REV SIGNAL
[C1921]

Malfunction is detected in engine speed signal that is output from 
ECM via CAN communication.
(Improper signal is input to the engine speed.)

Engine speed signal error

CONTROL UNIT
[ABNORMAL8]
[C1922]

An error is detected inside 4WAS main control unit.

4WAS main control unit error

STEERING ANGLE SEN
[NO CHANGE]
[C1923]

Malfunction is detected in steering angle sensor signal that is output 
from steering angle sensor via CAN communication.
[Steering angle sensor input signal error is detected when driving at 
60 km/h (37MPH) or more.]

Steering angle sensor input sig-
nal error

STEERING ANGLE SEN
[NO NEUT STATE]
[C1924]

Driving continuously at 10 km (6 mile) while the steering angle sen-
sor value is other than L10

°

 – R10

°

.

(Not detected in 4WAS front control unit fail-safe mode)

Steering angle sensor input sig-
nal error

AD CONVERTER
[C1925]

An error is detected inside 4WAS main control unit.

4WAS main control unit error

STEERING ANGLE SEN
[C1926]

Malfunction is detected in steering angle sensor signal that is output 
from steering angle sensor via CAN communication.
(When improper signal inputs to steering angle sensor and steering 
angle sensor itself detects the malfunction)

Steering angle sensor error

CONTROL UNIT
[ABNORMAL5]
[C1927]

An error is detected inside 4WAS main control unit.

4WAS main control unit error

CONTROL UNIT
[ABNORMAL9]
[C1928]

An error is detected inside 4WAS main control unit.

4WAS main control unit error

Items 

(CONSULT-III screen terms)

Diagnostic item is detected when...

Possible cause

DIAGNOSIS SYSTEM (4WAS MAIN CONTROL UNIT)

STC-45

< FUNCTION DIAGNOSIS >

[WITH 4WAS]

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*: Communication line between 4WAS front control unit and 4WAS main control unit

DATA MONITOR MODE

Display Item List

*: Communication line between 4WAS front control unit and 4WAS main control unit

CAN DIAGNOSTIC SUPPORT MONITOR

4WAS FRONT ECU
[C1930]

An error is detected on 4WAS front control unit side.
(4WAS front control unit fail safe mode)

4WAS front control unit fail-safe 
mode

4WAS FRONT ECU COMM
[C1931]

4WAS communication line* data communication error is detected.
(An error signal is detected from 4WAS front control unit.)

4WAS communication line/
4WAS front control unit/4WAS 
main control unit error

STEERING ANGLE SEN
[C1932]

If the steering angle sensor error is detected.
(Steering angle sensor output value is abnormal.)

Steering angle sensor input sig-
nal error

CONTROL UNIT
[C1933]

An error is detected inside 4WAS main control unit.

4WAS main control unit error

CAN COMM
[U1000]

When 4WAS main control unit is not transmitting or receiving CAN 
communication signal for 2 seconds or more.

CAN communication error

CONTROL UNIT (CAN)
[U1010]

When detecting error during the initial diagnosis of CAN controller of 
4WAS main control unit.

CAN communication line and 
4WAS main control unit/ECM/
ABS actuator and electric unit 
(control unit) error

Items 

(CONSULT-III screen terms)

Diagnostic item is detected when...

Possible cause

Monitor item (Unit)

Remarks

VHCL SPEED SE [km/h] or [mph]

The vehicle speed signal from ABS actuator and electric unit (control unit) is indicated with 
CAN communication line.

STEERING ANG [

°

]

The steering angle sensor signal from the steering angle sensor is indicated with CAN com-
munication line.

ENGINE SPEED [rpm]

The engine speed signal from ECM is indicated with CAN communication line.

STR ANGL SPD [deg/s]

The steering angle speed signal from the steering angle sensor is indicated with CAN com-
munication line.

POWER STR SOL [A]

The current value of the power steering solenoid valve is indicated.

RR ST ANG-MAI [V]

The voltage of the rear wheel steering angle sensor (main) is indicated.

RR ST ANG-SUB [V]

The voltage of the rear wheel steering angle sensor (sub) is indicated.

RR ST ANG-VOL [V]

The power supply voltage of the rear wheel steering angle sensor is indicated.

C/U VOLTAGE [V]

The power supply voltage value of 4WAS main control unit is indicated.

MOTOR VOLTAGE [V]

The voltage value of 4WAS rear motor is indicated.

MOTOR CURRENT [A]

The current value of 4WAS rear motor is indicated.

MTR CRNT OPE [A]

The current value input to 4WAS rear motor is indicated.

RR ANG OPE [deg]

The angle command value is indicated for activating 4WAS rear motor.

FR ANGLE OPE [

°

]

The front wheel angle value transmitted from 4WAS main control unit to 4WAS front control 
unit is indicated.

STOP LAMP SW [On/Off]

The stop lamp switch status is indicated.

HICAS RELAY [On/Off]

4WAS rear motor relay condition is indicated.

FAIL SAFE [On/Off]

The fail-safe mode status of 4WAS main control unit is indicated.

WARNING LAMP [On/Off]

4WAS warning lamp ON/OFF condition is indicated.

FRONT ECU FAIL [On/Off]

The fail-safe mode status of 4WAS main control unit transmitted from 4WAS front control unit 
via 4WAS communication line* is indicated.

FRONT ECU EX [On/Off]

The protection function mode status of 4WAS front control unit transmitted from 4WAS front 
control unit via 4WAS communication line* is indicated.

STC-46

< FUNCTION DIAGNOSIS >

[WITH 4WAS]

DIAGNOSIS SYSTEM (4WAS MAIN CONTROL UNIT)

Description

• The communication status and the number of errors of 4WAS main control unit, ECM, ABS actuator and

electric unit (control unit), 4WAS front control unit and the steering angle sensor are indicated.

• Error counter displays OK if any malfunction is not detected in the past. If the malfunction is detected, it dis-

plays 0. The upper limit of the counters is 39.

ACTIVE TEST MODE

Description

• 4WAS rear actuator assembly activation is checked according to the control signal from CONSULT-III.
• The control signal forcibly activates (ON/OFF) 4WAS rear assembly, performs the self-diagnosis and checks

each sensor in “SELF DIAGNOSTIC MODE”.

CAUTION:

Perform the active test while the vehicle is stopped.

Standard value

Item

PRSNT

PAST

TRANSMIT DIAG

OK / UNKWN

OK / 0 – 39 

ECM

OK / UNKWN

OK / 0 – 39 

VDC/TCS/ABS

OK / UNKWN

OK / 0 – 39 

STRG

OK / UNKWN

OK / 0 – 39 

4WAS

OK / UNKWN

OK / 0 – 39 

Select test item

Control signal

Remarks

SELF DIAGNOSTIC MODE

ON

CAUTION:

Perform the active test while the vehicle 
is stopped.

4WAS rear actuator assembly activates. It 
activates in the same direction as the steer-
ing angle by inputting the steering angle.

OFF

4WAS rear actuator assembly stops the ac-
tivation.

Monitor item

Active test “ON”

STEERING ANG

0

°

 (Neutral)

R 90

°

L 90

°

RR ST ANG-MAI

2.4 V

Approx. 4.4 V

Approx. 0.4 V

RR ST ANG-SUB

2.4 V

Approx. 4.4 V

Approx. 0.4 V

MOTOR CURRENT

No output (Approx. 0 A)

Output (change)