DTC C1784: Steering Sensor Signal Malfunction [08/2019 - ]: Procedure

1. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [08/2019 - ]

2. Perform a road test.
3. Check if DTCs C1784 and U0126 are output.

   Refer to DTC CHECK / CLEAR [08/2019 - ]

   Result

   Result	Proceed to
   DTC is not output or only DTC C1784 is output	A
   DTCs C1784 and U0126 are output	B

Result: 

B 

GO TO DTC U0126. Refer to  DTC U0100: Lost Communication with ECM / PCM "A"; DTC U0114: Lost Communication with Four-Wheel Drive Clutch Control Module; DTC U0122: Lost Communication with Vehicle Dynamics Control Module; DTC U0124: Lost Communication with Lateral Acceleration Sensor Module; DTC U0126: Lost Communication with Steering Angle Sensor Module; DTC U0140: Lost Communication with Body Control Module [08/2019 - ]  

Result: 

A 

See step  2

1. Check for steering sensor malfunction DTCs.

   Refer to DTC CHECK / CLEAR [08/2019 - ]

   Result

   Result	Proceed to
   DTC is not output	A
   DTC is output	B

Result: 

B 

GO TO VEHICLE STABILITY CONTROL SYSTEM (DIAGNOSTIC TROUBLE CODE CHART). Refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2019 - 08/2021]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2021 - ] 

Result: 

A 

See step  3

1. Disconnect the G104 steering sensor connector.
2. Measure the voltage and resistance according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   G104-4 (IG) - Body ground	Engine switch on (IG)	11 to 14 V
   G104-5 (BAT) - Body ground	Always	11 to 14 V

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G104-1 (ESS) - Body ground	Always	Below 1 Ω

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Steering Sensor)

3. Check that the steering sensor connector is not deformed or corroded.

   OK

   No deformation or corrosion.

   HINT: 

   If the steering sensor connector is defective, replace the spiral cable sub-assembly.

   Result

   Result
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  4

1. Turn the engine switch off.
2. Connect the Techstream to the DLC3.
3. Turn the engine switch on (IG).
4. Turn the Techstream on.
5. Enter the following menus: Chassis / Air suspension / Data List.
   AIR SUSPENSION
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Steering Angle	Steering angle/ Min.: -49152.0 deg Max.: 49150.5 deg	Actual steering angle Steering wheel turned left: reading increases Steering wheel turned right: reading decreases	-

   OK

   Steering wheel turning angle value changes when steering wheel is turned.

   Result

   Result
   OK
   NG

Result: 

OK 

REPLACE SUSPENSION CONTROL ECU. Refer to  REMOVAL [08/2015 - ] 

Result: 

NG 

REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  REMOVAL [08/2019 - ]