Circuit Description
This DTC is used in order to identify open stoplamp switch circuitry that prevents the stoplamp switch input from changing states when the brake is applied. This DTC is used in conjunction with DTC C1291 in order to determine the cause of an open stoplamp switch malfunction.
Conditions for Setting the DTC
This DTC sets after the following occur:
| • | Initialization is completed. |
| • | The stoplamp/BTSI switch input voltage is out of specification for 1 second (indicating an open circuit). |
Action Taken When the DTC Sets
| • | A malfunction DTC is stored. |
| • | The TCS is disabled. |
| • | The TRACTION CONTROL indicator is turned ON. |
| • | The ABS remains functional. |
Conditions for Clearing the DTC
| • | The condition for DTC is no longer present and you used scan tool Clear DTCs function. |
| • | The condition for DTC is no longer present and you used the On-Board Clear DTCs function. |
| • | The EBTCM does not detect the DTC in 50 drive cycles. |
Diagnostic Aids
| • | It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. |
| • | An intermittent malfunction can be caused by poor connections, broken insulation, or a wire that is broken inside the insulation. |
| • | If an intermittent malfunction exists, refer to Intermittents and Poor Connections . |
| • | This condition may be cause by the following: |
| - | The stoplamp/BTSI switch circuit is open. |
| - | All brake lamps are open. |
| - | The brake lamp switch is open or misadjusted. |
| - | The brake lamp ground is open. |
| - | The circuit has a wiring problem, terminal corrosion, or poor connections. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check |
2 | Press the brake pedal. Do the brake lights come on? | -- | Go to Step 3 | Go to Step 6 |
Is the voltage within the specified range? | Battery Voltage | Go to Step 4 | Go to Step 5 | |
4 | Replace the EBTCM. Refer to Electronic Brake Control Module Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check | -- |
5 | Repair the open or high resistance in CKT 20. Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | Go to Diagnostic System Check | -- |
6 | Inspect the STOP LP fuse in the underhood fuse block. Is the fuse OK? | -- | Go to Step 7 | Go to Step 11 |
7 |
Is the voltage within specifications? | Battery Voltage | Go to Step 9 | Go to Step 8 |
8 | Repair the open in CKT 1540. Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | Go to Diagnostic System Check | -- |
Connect a fused jumper wire between the stoplamp/BTSI switch harness connector terminal A and terminal B. Do the brake lamps turn on? | -- | Go to Step 10 | Go to Step 5 | |
10 | Adjust or repair the stoplamp/BTSI switch as necessary. Refer to Stop Lamp Switch Adjustment or Stop Lamp Switch Replacement in Hydraulic Brakes. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
11 |
Important: Do not press the brake pedal. Is the fuse OK? | -- | Go to Step 13 | Go to Step 12 |
12 | Repair the short to ground in CKT 1540. Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | Go to Diagnostic System Check | -- |
13 |
Is the fuse OK? | -- | Go to Diagnostic System Check | Go to Step 14 |
14 |
Is the fuse OK? | -- | Go to Step 4 | Go to Step 15 |
15 | Repair the short to ground in CKT 20. Refer to Wiring Repairs in Wiring Systems. Is the circuit repair complete? | -- | Go to Diagnostic System Check | -- |
