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