The Stoplamps Are On Continuously
Normal Operation and Fault Conditions
REFER to: Exterior Lighting - System Operation and Component Description (417-01 Exterior Lighting, Description and Operation).
DTC Fault Trigger Conditions
DTC | Description | Fault Trigger Conditions |
|---|---|---|
C0040:12 Brake Pedal Switch "A": Circuit Short To Battery | An on-demand DTC that sets when the BCM detects a short to voltage from the stoplamp switch input circuit during the on-demand self-test. |
Possible Sources
Wiring, terminals or connectors Stoplamp switch PCM BCM
PINPOINT TEST D : THE STOPLAMPS ARE ON CONTINUOUSLY
D1 CHECK THE STOPLAMP SWITCH
Ignition OFF. Disconnect: Stoplamp Switch C278. Ignition ON.
Do the stoplamps continue to illuminate?
Yes | GO to D2 |
|---|---|
No | INSTALL a new brake pedal position (stoplamp) switch. REFER to: Stoplamp Switch (417-01 Exterior Lighting, Removal and Installation). |
D2 CHECK THE PCM (POWERTRAIN CONTROL MODULE)
Ignition OFF. Disconnect: PCM C1551B (2.3L). Disconnect: PCM C1381B (3.7L). Disconnect: PCM C175B (5.0L). Ignition ON.
Do the stoplamps continue to illuminate?
Yes | GO to D3 |
|---|---|
No | GO to D4 |
D3 CHECK THE STOPLAMP SWITCH INPUT CIRCUIT FOR A SHORT TO VOLTAGE
2016 Mustang workshop publication supplied to Mustang Atlas. Original technical text and illustrations; HTML formatting by Mustang Atlas. Source page numbering is retained for traceability. Follow the configuration, revision, warnings, and cross-references in the material. About this edition.