SAAB WIS ONLINE

P1577

Read the instructions below then start the fault diagnostic procedure.

Symptom: CHECK ENGINE. Cruise control not working.

P1577


Brake Light Switch Circuit. Short to Ground.


Fault symptoms


CHECK ENGINE.

Cruise control not working.


On-Board Diagnostics

Type of diagnosis:


- Continuous. However, it is interrupted once the fault criteria have been fulfilled and does not restart until the next driving cycle.


Enable criteria: (Conditions that must be fulfilled for diagnostics to be performed.)


- Global conditions for this diagnostic trouble code: When starting the engine, the atmospheric pressure must exceed 78 kPa and the temperature of the coolant and the intake air must exceed -7°C.

- Engine running. The vehicle speed has dropped from 40 km/h to 0 km/h in 2 to 12s on 5 occasions.


Fault criteria: (When enable criteria have been fulfilled, diagnostics will check if the fault criteria have been fulfilled.)


- No battery voltage applied to the control module input on any occasion.


Dependents: (Once fault criteria have been fulfilled, a number of other diagnostics must report OK before the diagnostic trouble code can finally be generated.)


- None.


System reaction to a fault: (Once the fault criteria have been fulfilled, certain measures will sometimes be taken.)


- Cruise control is blocked.


OK report: (This diagnosis may be included as a dependent to another diagnosis and must therefore report OK even if it is continuous. The OK report is also used in fault handling to count down the fault counter.)


- Brake pedal depressed and then released on one occasion.


Fault handling: (Refer to section “Fault diagnosis, general” for more information.)


- Type III.


Diagnostic help

Fault diagnosis concerns an electrical fault in the connecting lead.

Diagnostic tool functions related to this fault:


Diagnostic status for the diagnosis.

Brake lights, unit ON/OFF.


Refer also to the description of readings under ”Fault diagnosis, general” for more information

Check the wiring

Jiggle the wiring harness at several points and in different directions to check if there are intermittent breaks and short-circuits in the leads. Observe the multimeter, test lamp or diagnostic instrument during the test.

See .