DTC C1595/55: Lost Communication with Steering Angle Sensor Module; DTC C15C4/68: Steering Angle Signal (Test Mode DTC): Procedure

1. Check for DTCs in the CAN communication system. Refer to DIAGNOSIS SYSTEM .
   RESULT
   
   

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

B → See step   7 

A: Go to next step 

1. Check if a steering angle sensor that complies with the vehicle specifications is installed.

   OK

   A steering angle sensor that complies with the vehicle specifications is installed.

NG → See step   6 

OK: Go to next step 

Fig 1: Checking Harness And Connector (Steering Control ECU - Steering Angle Sensor)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the A41 steering control ECU connector.
2. Disconnect the L21 steering angle sensor connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   A41-10 (SS1-) - L21-7 (SS1-)	Always	Below 1 Ω
   A41-19 (SS1+) - L21-8 (SS1+)	Always	Below 1 Ω
   A41-19 (SS1+) - Body ground	Always	10 kΩ or higher
   A41-10 (SS1-) - Body ground	Always	10 kΩ or higher
   A41-19 (SS1+) - A41-10 (SS1-)	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the A41 steering control ECU connector.
   Fig 2: Identifying A41 Steering Control ECU Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT: 

   The resistance must be measured after the steering angle sensor connector is connected.

2. Adjust the shift lever to neutral.
3. Jack up the vehicle.
4. Turn the engine switch on (IG).
5. Check the waveform of the steering angle sensor using an oscilloscope.

   Standard voltage

   Tester Connection	Switch Condition	Specified Condition
   A41-19 (SS1+) - A41-10 (SS1-)	Engine switch on (IG), rotate steering wheel slowly	Pulse generation (0 to 5 V)

   HINT: 

   The output voltage should fluctuate up and down similarly to the diagram when the wheel is turned slowly.

NG → See step   6 

OK → See step   5