DTC C1294 Brake Lamp Switch Circuit Always Active w/NW9
Circuit Description
The EBCM uses this stoplamp switch circuit for various performance measures within DRP/ABS/TCS/VSES. This DTC is set if the EBCM has determined that the stoplamp switch is continously ON. TCS cannot be activated when the stoplamp switch is ON
Conditions for Running the DTC
The vehicle speed is greater than 40 km/h (25 mph).
Conditions for Setting the DTC
The stop lamp switch input was active for 2 consecutive ignition cycles.
Action Taken When the DTC Sets
| • | The EBCM disables the TCS for the duration of the ignition cycle. |
| • | The TRACTION OFF indicator turns ON. |
| • | The ABS remains functional. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and the DTC is cleared with a scan tool. |
| • | The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
Diagnostic Aids
Possible causes of this DTC are the following conditions:
| • | The stop lamp switch circuit is shorted to voltage. |
| • | The stop lamp switch is misadjusted. |
| • | The stop lamp switch is stuck closed. |
| • | A brake pedal that is binding. |
| • | Both brake light bulbs are burned out. |
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |||||||
Does the scan tool display Released? | -- | Go to Step 3 | Go to Step 4 | |||||||
3 |
Does the Brake Switch - ABS Input parameter change state? | -- | Go to Diagnostic Aids | Go to Step 4 | ||||||
4 |
Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 5 | ||||||
5 |
Does the scan tool display Released? | -- | Go to Step 8 | Go to Step 6 | ||||||
6 | Test the stop lamp input circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 7 | ||||||
7 | Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 9 | ||||||
8 | Inspect for poor connections at the harness connector of the stoplamp/auto trans shift lock control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 | ||||||
9 |
Important: Perform the setup procedure for the EBCM. An unprogrammed EBCM will
result in the following conditions:
Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | Go to Step 11 | -- | ||||||
10 | Replace the stoplamp/auto trans shift lock control switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the replacement? | -- | Go to Step 11 | -- | ||||||
11 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
