DTC C1784: Steering Angle Sensor Communication Error: Procedure

1. Clear the DTC. Refer to DTC CHECK / CLEAR .
2. Perform a road test.
3. Check for DTC. Refer to DTC CHECK / CLEAR . Check if DTC C1784 and U0126 are output.

   Result

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

B → See step   5 

A: Go to next step 

1. Check for DTC. Refer to DTC CHECK / CLEAR . Check if DTC C1231/31 is output.

   Result

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

B → See step   6 

A: Go to next step 

1. Disconnect the L21 sensor connector.
   Fig 1: Identifying L21 Sensor Connector

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage and resistance according to the value(s) in the table below.

   Standard voltage

   Tester Connection	Switch Condition	Specified Condition
   L21-1 (IG) - Body ground	Engine switch on (IG)	11 to 14 V

   Standard resistance

   Tester Connection	Condition	Specified Condition
   L21-2 (ESS) - Body ground	Always	Below 1 Ω

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

   OK

   No deformation or corrosion.

   HINT: 

   If the steering angle sensor's connector is defective, replace the sensor.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

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

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Steering Angle	Steering angle sensor reading/ min.: -49152.0 deg max.: 49150.5 deg	Actual steering angle Left turn: reading increases Right turn: reading decreases	-

   OK

   Steering wheel turning angle value changes.

NG → See step   7 

OK → See step   8