Fault Conditions

P1577

Brake Light Switch Circuit. Short to Ground.







Fault symptoms
- CHECK ENGINE.
- Cruise control not working.

On-Board Diagnostics

Type of diagnosis:
- Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.

Enable criteria:
- Engine running. Vehicle speed has dropped from 40 km/h to 3 km/h in 2 to 12 s on 5 occasions.

Fault criteria:
- No battery voltage on control module input on any occasion.

Dependents:
- None.

System reaction to a fault:
- Cruise control blocked.

OK report:
- Brake pedal depressed and then released on one occasion.

Fault handling: (For more information, Fault Handling III, Other Emission-Related Components and Function)

- Type III.

Diagnostic help
Fault diagnosis concerns an electrical fault in the connecting leads.

Functions in the diagnostic tool related to the fault:
- Diagnostic status for the diagnosis.
- Brake light, unit ON/OFF.

For more information, refer to scan tool testing. Menu Read Values

Checking the wiring
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.

Proceed to Diagnostic Procedures Checking Brake-Lights Functionality