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Home >> Infiniti >> 2013 >> M56 x >> Repair and Diagnosis >> Steering >> Power Steering >> Steering Control System (With 4WAS) >> System Description >> System >> 4WAS System >> 4WAS SYSTEM: Fail-safe (4WAS Main Control Unit)
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4WAS SYSTEM: Fail-safe (4WAS Main Control Unit)

4WAS system enters in the fail-safe mode (4WAS system stopped) and 4WAS warning lamp turns ON if an error is detected in 4WAS system (4WAS main control unit) component part.

DTC Error area and root cause Contents of fail-safe
C1900 An error is detected inside 4WAS main control unit. 4WAS system stopped.
C1901 An error is detected inside 4WAS main control unit.
C1902 4WAS rear motor current error is detected. (4WAS rear motor current output direction differs.)
C1903 4WAS rear motor current error is detected. (Current is input to 4WAS main control unit if 4WAS main control unit output is "OFF".)
C1904 4WAS rear motor current error is detected. (4WAS rear motor output is overcurrent.)
C1905 An error is detected inside 4WAS main control unit.
C1906 An error is detected inside 4WAS main control unit.
C1907 An error is detected inside 4WAS main control unit.
C1908 An error is detected inside 4WAS main control unit.
C1909 An error is detected inside 4WAS main control unit.
C1910 4WAS rear motor inside error is detected. (4WAS rear motor does not move or the rear wheel angle sensor does not change if 4WAS main control unit output is 14 A or more.)
C1911 4WAS rear motor voltage error is detected. (4WAS rear motor voltage is low.)
C1912 4WAS rear motor voltage error is detected. (Voltage is applied to 4WAS main motor when 4WAS main control unit output is "OFF".)
C1913 4WAS rear motor current error is detected. (4WAS rear motor does not move or the rear wheel angle sensor output does not change when 4WAS main control unit output is 18 A or more, and 4WAS main motor output is low.)
C1914 The rear wheel angle sensor power supply error is detected.
C1915 The rear wheel angle sensor signal (main) error is detected.
C1916 If the rear wheel angle sensor signal (sub) error is detected.
C1917 The rear wheel angle sensor signal (main and sub) error is detected. (The output signal value differs temporarily between main and sub.)
C1918 The rear wheel angle sensor signal (main and sub) error is detected. (The output signal value differs between main and sub.)
C1919 Malfunction is detected in vehicle speed signal that is output from ABS actuator and electric unit (control unit) via CAN communication. (Improper signal inputs while driving.)
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)
C1921 Malfunction is detected in engine speed signal that is output from ECM via CAN communication. (Improper signal is input engine speed.) When DTC "C1921" is detected before starting the engine.
When DTC "C1921" is detected after starting the engine. -
C1922 An error is detected inside 4WAS main control unit. 4WAS system stopped.
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.]
C1924 Driving continuously at 10 km (6 mile) or more while the steering angle sensor value is not L10° - R10°. (Not detected in 4WAS front control unit fail-safe mode)
C1925 An error is detected inside 4WAS main control unit.
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)
C1927 An error is detected inside 4WAS main control unit.
C1928 An error is detected inside 4WAS main control unit.
C1930 An error is detected on 4WAS front control unit side. (4WAS front control unit fail-safe mode)
C1931 4WAS communication line(1) data communication error is detected. (An error signal is detected from 4WAS front control unit.)
C1932 If the steering angle sensor error is detected. (Steering angle sensor output value is abnormal.)
C1933 An error is detected inside 4WAS main control unit.
U1000 When 4WAS main control unit is not transmitting or receiving CAN communication signal for 2 seconds or more. When 4WAS main control unit is not receiving following CAN communication signal.
  • Drive mode select switch signal
Mode is fixed to the mode when a malfunction of drive mode selector occurs. The mode is fixed to STANDARD mode after ignition switch OFF→ ON.
When 4WAS main control unit is not receiving following CAN communication signal or 4WAS communication signal.
  • Steering angle sensor
  • Vehicle speed signal
  • Engine speed signal
  • 4WAS system control signal
4WAS system stopped.
U1010 When detecting error during the initial diagnosis of CAN controller of 4WAS main control unit.
(1) Communication line between 4WAS front control unit and 4WAS main control unit