Refer to Engine Controls Schematic
Generator, Brake and Traction Controls, Oil level and BTSI Switches
for a wiring diagram.
Circuit Description
This diagnostic test functions on the assumption that a brake application causes a sudden decrease in non-drive wheel speed. The extended travel brake switch is normally closed. When the extended travel brake switch is closed, the powertrain control module (PCM) senses low voltage on the extended travel brake switch signal circuit. If the PCM senses low voltage on the extended travel brake switch signal circuit when the switch should be open, this DTC sets.
Conditions for Running the DTC
| • | The engine speed is more than 700 RPM. |
| • | The engine has been operating for more than 2 seconds. |
| • | The wheel speed must be more than 30 MPH in order to enable the diagnostic. The diagnostic will disable when the wheel speed is less than 10 MPH. |
| • | The vehicle speed is decreasing at a rate of more than 10.4 MPH over a one second period. |
Conditions for Setting the DTC
| • | The PCM detects voltage on the extended travel brake switch circuit when the switch should be open. |
| • | The above conditions are present for 1.5 seconds. |
Action Taken When the DTC Sets
The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.
Conditions for Clearing the MIL/DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction free warm-up cycles. |
| • | The PCM receives a clear code command from the scan tool. |
Diagnostic Aids
Important: Remove any debris from the component module connector surfaces before servicing the component module. Inspect the component module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the components modules.
In order to adjust the extended travel brake switch perform the following procedure:
- 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 the CKT 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 | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||
Does the display indicate Applied? | -- | Go to Diagnostic Aids | ||
3 | Check the adjustment of the extended travel brake switch. Refer to Diagnostic Aids . Was an adjustment necessary? | -- | ||
Does the display indicate Applied? | -- | |||
5 |
Is the voltage more than the specified value? | 0.5 V | ||
6 | Repair the short to voltage on the extended travel brake switch signal circuit. Refer to Wiring Repairs in Wiring Systems . Did you complete the repair? | -- | -- | |
7 | Replace the extended travel brake switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the repair? | -- | -- | |
8 |
Important:: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the repair? | -- | -- | |
Does the scan tool indicate that this test failed? | -- | |||
10 | Select the Capture Info option and the Review Info option on the scan tool. Are any DTCs displayed that you have not diagnosed? | -- | Go to applicable DTC table | System OK |
