Circuit Description
The Brake Lamp Switch is a normally open switch. When the Brake Lamp Switch is closed, the TAC senses ignition voltage on the Brake Lamp Switch signal circuit.
If the TAC senses a voltage on the Brake Lamp Switch signal circuit when the Brake Lamp Switch should be open, this DTC sets.
Conditions for Setting the DTC
| • | Engine speed is greater than 700 RPM. |
| • | Engine operates longer than 2.0 second. |
| • | Wheel speed must be greater than 30 MPH in order to enable the diagnostic. The diagnostic will disable when the wheel speed is below 10 MPH. |
| • | Vehicle speed is decreasing at a rate greater than 10.4 MPH over a one second period. |
| • | The TAC does not detect voltage on the Brake Lamp Switch circuit when the Brake Lamp Switch should be closed. |
| • | The above conditions present for 1.5 seconds. |
Action Taken When the DTC Sets
| • | The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | A last test failed, or the current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic. |
| • | Use a scan tool in order to clear the MIL/DTC. |
Diagnostic Aids
In order to adjust the Brake Lamp Switch perform the following:
- With the brake pedal depressed, insert the Brake Lamp Switch into the retainer until the switch body seats in the retainer. You can hear clicks as you push the threaded portion of the switch through the retainer.
- Slowly pull the brake pedal fully rearward against the stop until you can no longer hear the clicks.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step determines if the fault is present.
-
This step checks for a Stop Lamp Switch circuit for being shorted to B+.
-
This DTC will not report a pass. The scan tool status for this DTC will never report a pass. The scan tool will only display when the diagnostic fails. The repair is not complete if the scan tool indicates that the diagnostic ran and failed.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Does the display indicate Applied? | -- | Fault not present. Refer to Diagnostic Aids | ||
3 | Check the adjustment of the Stop Lamp switch. Refer to Diagnostic Aids . Was an adjustment necessary? | -- | ||
Does the display indicate Applied? | -- | |||
5 |
Is the voltage greater than the specified value? | 0.5V | ||
6 | Repair the short to voltage on the Stop Lamp signal circuit. Is the action complete? | -- | -- | |
7 | Replace the Stop Lamp switch. Is the action complete? | -- | -- | |
8 | Replace the TAC module. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement Is the action complete? | -- | -- | |
Does the scan tool indicate that this test failed? | -- | |||
10 | Select the Capture Info option and the Review Info option using the scan tool. Are any DTCs displayed that you have not diagnosed? | -- | Go to applicable DTC table | System OK |
