Circuit Description
This circuit detects an open stoplamp/BTSI switch in the non-ABS mode. The EBCM/EBTCM looks for a deceleration rate that indicates braking action and requires several repeats of this detection method in order to verify this assumption. In each case, the TCS will not be available since the EBCM/EBTCM detects no stoplamp/BTSI switch voltage.
Conditions for Setting the DTC
The stoplamp switch remains open for 3 deceleration cycles.
Action Taken When the DTC Sets
| • | A malfunction DTC is stored. |
| • | The TCS is disabled. |
| • | The TRACTION OFF indicator is turned ON. |
| • | The ABS remains functional. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and you used the scan tool Clear DTC function. |
| • | The EBCM/EBTCM does not detect the DTC in 50 drive cycles. |
Diagnostic Aids
| • | If any wheel speed sensor DTCs are present, diagnose them first. Refer to Diagnostic Trouble Code (DTC) List . |
| • | 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 can be caused by a poor connection, broken insulation, or a wire that is broken inside the insulation. |
| • | If an intermittent malfunction exists, refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. |
| • | This DTC may be cause by one of the following: |
| - | An open stoplamp/BTSI switch. |
| - | An open brake fuse. |
| - | A misadjusted stoplamp/BTSI switch. |
| - | Erratic wheel speeds. |
| - | A wiring problem, terminal corrosion, or a poor connection in the circuit. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step checks if the stoplamp switch and power distribution are OK.
-
This step checks for voltage at the EBTCM.
-
This step checks the stoplamp switch.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |
2 | Are any wheel speed sensor DTCs present? | -- | Go to Step 3 | |
Press the brake pedal. Do the brake lights illuminate? | -- | Go to Step 4 | Go to Step 7 | |
Is the voltage within the specified range? | Battery Voltage | Go to Step 5 | Go to Step 6 | |
5 | Replace the EBCM/EBTCM. Refer to Electronic Brake Control Module Replacement . Did you complete the repair? | -- | -- | |
6 | Repair the open or high resistance in CKT 17 (WHT) or CKT 20 (LT BLU). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
7 | Inspect the BRK/HZRD LPS fuse in the IP fuse block. Is the fuse OK? | -- | Go to Step 8 | Go to Step 12 |
8 |
Is the voltage within the specified range? | Battery voltage | Go to Step 10 | Go to Step 9 |
9 | Repair the open in CKT 140 (ORN). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
Connect a fused jumper wire between the stoplamp/BTSI switch harness connector terminal A and terminal B. Do the brake lamps illuminate? | -- | Go to Step 11 | Go to Step 6 | |
11 | Adjust or repair the stoplamp/BTSI switch as needed. Refer to Stop Lamp Switch Adjustment or Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the repair? | -- | -- | |
12 |
Is the fuse OK? | -- | Go to Step 14 | Go to Step 13 |
13 | Repair the short to ground in CKT 140 (ORN). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
14 |
Is the fuse OK? | -- | Go to Step 15 | |
15 |
Is the fuse OK? | -- | Go to Step 5 | Go to Step 16 |
16 | Repair the short to ground in CKT 17 (WHT) or CKT 20 (LT BLU). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- |
