Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC C0040-62 (2017 2018 2019)
DTC C0040-62 : Brake Light Switch Failure (Stuck)
NOTE:
- Before you troubleshoot, review the general troubleshooting information .
- Troubleshoot any PGM-FI DTCs first .
| DTC Description | DTC | Freeze Frame |
|---|---|---|
| C0040-62 Brake Light Switch Failure (Stuck) |
DTC (VSA)
- Problem verification
-1. Turn the vehicle to the ON mode.
-2. Clear the DTC with the HDS.
-3. Turn the vehicle to the OFF (LOCK) mode, then start the engine.
-4. Test-drive the vehicle at 13 mph (20 km/h) or more for more than 6 minutes.
-5. Drive immediately at speed of 25 mph (40 km/h) or more, then press the brake pedal and stop the vehicle.
NOTE: Drive the vehicle on the road, not on a lift.
-6. Repeat steps 1-4 through 1-5, 3 times.
-7. Check for DTCs with the HDS.
DTC Description DTC Freeze Frame C0040-62 Brake Light Switch Failure (Stuck) Is DTC C0040-62 indicated?
YES
The failure is duplicated. Go to step 2.
NO
Intermittent failure, the system is OK at this time. Refer to intermittent failures troubleshooting . If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.
- Brake pedal position switch signal check (VSA modulator-control unit)
-1. Check the parameter(s) below with the HDS.
Signal Current conditions Values Unit BRAKE SWITCH Does the signal change ON and OFF when the brake pedal is pressed and released?
YES
Check for loose terminals and poor connections in the VSA modulator-control unit 38P connector. If they are OK, replace the VSA modulator-control unit .
NO
Go to step 3.
- Brake pedal height check
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Check the brake pedal height .
Is the brake pedal height OK?
YES
Go to step 4.
NO
- Brake pedal position switch check
-1. Check the brake pedal position switch .
Is the brake pedal position switch OK?
YES
Go to step 5.
NO
- Brake light relay check
-1. Remove the brake light relay .
-2. Check the brake light relay .
Is the brake light relay OK?
YES
Go to step 6.
NO
- Brake pedal position switch signal check (PGM-FI system) 1
-1. Install the brake light relay .
-2. Check the parameter(s) below with the HDS while releasing the brake pedal.
Signal Current conditions Values Unit BRAKE SWITCH Does it indicate OFF when the pedal is released?
YES
Go to step 7.
NO
Go to step 14.
- Brake pedal position switch signal check (PGM-FI system) 2
-1. Check the parameter(s) below with the HDS while pressing the brake pedal.
Signal Current conditions Values Unit BRAKE SWITCH Does it indicate ON when the pedal is pressed?
YES
Check for loose terminals and poor connections in the VSA modulator-control unit 38P connector. If they are OK, replace the VSA modulator-control unit .
NO
Go to step 8.
- Fuse check
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Check the following fuse.
Fuse No. A4 (10 A) *1 No. A6 (10 A) *2 Location Under-hood fuse/relay box *1: With AC Power Outlet *2: Without AC Power Outlet Is the fuse OK?
YES
The fuse is OK. Reinstall the fuse, then go to step 9.
NO
Go to step 11.
- Open wire check (+B STOP HORN line)
-1. Disconnect the following connector.
Brake pedal position switch 4P connector -2. Measure the voltage between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Brake pedal position switch 4P connector: disconnected Test point 1 Brake pedal position switch 4P connector (female terminals) No. 2: Test point 2 Body ground Is there battery voltage?
YES
Go to step 10.
NO
Repair an open in the wire between the under-hood fuse/relay box and the brake pedal position switch.
- Open wire check (STOP SW line)
-1. Jump the SCS line with the HDS, and wait more than 1 minute.
-2. Disconnect the following connector.
PCM connector A (51P) -3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Brake pedal position switch 4P connector: disconnected PCM connector A (51P): disconnected Test point 1 Brake pedal position switch 4P connector (female terminals) No. 1: Test point 2 PCM connector A (51P) No. 25 Is there continuity?
YES
Go to step 16.
NO
Repair an open in the wire between the brake pedal position switch and the PCM.
- Shorted wire check (+B STOP HORN line)
-1. Disconnect the following connector.
Brake pedal position switch 4P connector -2. Remove the brake light relay .
-3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Brake pedal position switch 4P connector: disconnected Brake light relay: removed Test point 1 Brake pedal position switch 4P connector (female terminals) No. 2: Test point 2 Body ground Is there continuity?
YES
Repair a short to ground in the wire between the under-hood fuse/relay box and the brake pedal position switch.
NO
Go to step 12.
- Shorted wire check (STOP SW line)
-1. Jump the SCS line with the HDS, and wait more than 1 minute.
-2. Disconnect the following connector.
PCM connector A (51P) -3. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Brake pedal position switch 4P connector: disconnected Brake light relay: removed PCM connector A (51P): disconnected Test point 1 PCM connector A (51P) No. 25 Test point 2 Body ground Is there continuity?
YES
Repair a short to ground in the wire between the brake pedal position switch and the PCM.
NO
Go to step 13.
- Shorted wire check (BRAKE DIAG line)
-1. Disconnect the following connector.
VSA modulator-control unit 38P connector -2. Check for continuity between test points 1 and 2.
Test condition Vehicle OFF (LOCK) mode Brake pedal position switch 4P connector: disconnected Brake light relay: removed PCM connector A (51P): disconnected VSA modulator-control unit 38P connector: disconnected Test point 1 VSA modulator-control unit 38P connector No. 5 Test point 2 Body ground Is there continuity?
YES
Repair a short to ground in the wire between the brake light relay and the VSA modulator-control unit.
NO
Go to step 16.
- Shorted wire check (STOP SW line to power)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Jump the SCS line with the HDS, and wait more than 1 minute.
-3. Disconnect the following connectors.
PCM connector A (51P) Brake pedal position switch 4P connector -4. Remove the brake light relay .
-5. Turn the vehicle to the ON mode.
-6. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode PCM connector A (51P): disconnected Brake pedal position switch 4P connector: disconnected Brake light relay: removed Test point 1 PCM connector A (51P) No. 25 Test point 2 Body ground Is there 0.1 V or more?
YES
Repair a short to power in the wire between the brake pedal position switch and the PCM.
NO
Go to step 15.
- Shorted wire check (BRAKE DIAG line to power)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Disconnect the following connector.
VSA modulator-control unit 38P connector -3. Turn the vehicle to the ON mode.
-4. Measure the voltage between test points 1 and 2.
Test condition Vehicle ON mode PCM connector A (51P): disconnected Brake pedal position switch 4P connector: disconnected Brake light relay: removed VSA modulator-control unit 38P connector: disconnected Test point 1 VSA modulator-control unit 38P connector No. 5 Test point 2 Body ground Is there 0.1 V or more?
YES
Repair a short to power in the wire between the brake light relay and the VSA modulator-control unit.
NO
Go to step 16.
- PCM check (substitution)
-1. Turn the vehicle to the OFF (LOCK) mode.
-2. Substitute a known-good PCM .
-3. Reconnect all connectors.
-4. Turn the vehicle to the ON mode.
-5. Clear the DTC with the HDS.
-6. Turn the vehicle to the OFF (LOCK) mode, then start the engine.
-7. Test-drive the vehicle at 13 mph (20 km/h) or more for more than 6 minutes.
-8. Drive immediately at speed of 25 mph (40 km/h) or more, then press the brake pedal and stop the vehicle.
NOTE: Drive the vehicle on the road, not on a lift.
-9. Repeat steps 16-7 through 16-8, 3 times.
-10. Check for DTCs with the HDS.
DTC Description DTC Freeze Frame C0040-62 Brake Light Switch Failure (Stuck) Is DTC C0040-62 indicated?
YES
Check for loose terminals and poor connections in the VSA modulator-control unit 38P connector. If they are OK, replace the VSA modulator-control unit .
NO
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.