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Code No. C1340 Stoplight switch
 
 
caution
  • When more than one stop light do not illuminate due to a blown bulb, this diagnostic trouble code may be set. Diagnose the rear combination lights (Refer to GROUP 54A, Rear Combination light, Troubleshooting, The Stop lights do not Illuminate or go out Normally ).
  • If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C, CAN Bus Diagnostics Table ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.
  • When the hydraulic unit (integrated with ASC-ECU) is replaced, always carry out the calibration of the steering wheel sensor and the G and yaw rate sensor (Refer to and ).
 
 
OPERATION
The ASC-ECU monitors the ON/OFF signals from the stop light switch and the pressure sensor (incorporated in the hydraulic unit).
 
 
DIAGNOSTIC TROUBLE CODE SET CONDITIONS
This diagnostic trouble code is set in the following case.
  • When the vehicle has been driven for a long time with the stop light switch turned ON.
  • The vehicle is being stopped although the stop light switch remains off.
 
 
PROBABLE CAUSES
  • The CAN bus line is defective.
  • Blown stop light bulbs.
  • Improper adjustment of stop light switch installation position.
  • Malfunction of stop light switch.
  • Malfunction of ETACS-ECU.
  • Damaged harness wires and connectors.
  • Malfunction of the hydraulic unit assembly (integrated with ASC-ECU).
 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-III), diagnose the CAN bus lines.
Use scan tool (M.U.T.-III) to diagnose the CAN bus lines.
Is the check result normal?
Go to Step 3.
Repair the CAN bus lines. (Refer to GROUP 54C, Troubleshooting ). On completion, go to Step 2.
 
STEP 2. Diagnostic trouble code recheck after resetting CAN bus lines
Is the check result normal?
Go to Step 3.
This diagnosis is complete.
 
STEP 3. Check the stop light and the high-mounted stop light for proper function.
Check the stop light and the high-mounted stop light for proper operation when the brake pedal is depressed. Check that the stop light illuminates when the brake pedal is depressed and that it goes out when the brake pedal is released.
OK:
  • When the brake pedal is released: OFF
  • When the brake pedal is depressed: ON
Is the check result normal?
Go to Step 6.
Go to Step 4.
 
STEP 4. Check for stop light switch installation
Refer to GROUP 35A, On-vehicle Service, Brake Pedal Check and Adjustment .
Is the check result normal?
Go to Step 5.
Install the stop light switch correctly (Refer to GROUP 35A, On-vehicle Service, Brake Pedal Check and Adjustment ). Then go to Step 9.
 
STEP 5. Check the stop light switch continuity.
Refer to GROUP 35A, Brake Pedal and Stop light Switch Check .
Is the check result normal?
Go to Step 6.
Replace the stop light switch (Refer to GROUP 35A, Brake Pedal <LHD>, <RHD>). Then go to Step 9.
 
STEP 6. Voltage measurement at the ETACS-ECU connector
(1) Connector check: ETACS-ECU connector, stop light switch connector
(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between the stop light switch terminal and body ground.
OK:
  • When the brake pedal is released: 1V or less
  • When the brake pedal is depressed: Approx. system voltage
Is the check result normal?
Go to Step 7.
The power supply circuit may be open or short. Repair the connectors or the wiring harness wires between the ETACS-ECU connector and the stop light switch connector. Then go to Step 9.
 
STEP 7. Diagnostic trouble code recheck.
Check again if the diagnostic trouble code is set.
(1) Erase the set diagnostic trouble code.
(2) Ignition switch: "LOCK" (OFF).
(3) Ignition switch: "ON".
Is diagnostic trouble code No. C1340 set?
Replace the ETACS-ECU. (Refer to GROUP 54A, ETACS-ECU ). Then go to Step 8.
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
 
STEP 8. Diagnostic trouble code recheck
Check again if the diagnostic trouble code is set.
(1) Erase the set diagnostic trouble code.
(2) Ignition switch: "LOCK" (OFF).
(3) Ignition switch: "ON".
Is diagnostic trouble code No. C1340 set?
Replace the hydraulic unit assembly (integrated with ASC-ECU) (Refer to ). Then go to Step 9.
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).
 
STEP 9. Diagnostic trouble code recheck
Check again if the diagnostic trouble code is set.
(1) Erase the set diagnostic trouble code.
(2) Ignition switch: "LOCK" (OFF).
(3) Ignition switch: "ON".
Is diagnostic trouble code No. C1340 set?
Return to Step 3.
The procedure is complete.