P1576

BRAKE LIGHT SWITCH





Symptom Of Fault.
The CHECK ENGINE lamp (MIL) is on.
Only basic boost pressure.

Conditions.
Engine running
Braking 6 times from 35 km/h to 0 km/h.
Each braking manoeuvre shorter than 10 seconds.
No status change on the input from the brake light switch.
P1576: Short circuit to battery positive (B+).
P1577: short circuit to ground/open circuit

Diagnostic Help.
The status ("ON/OFF") of the brake light switch can be ascertained by means of the ISAT scan tool.
- Select "ON/OFF".
- Select "BRAKE LIGHT SWITCH".

Checking The Wiring
Intermittent faults may occur as a result of occasional short circuits and breaks in the wiring. Jiggle the leads and in-line connectors at several places and in different directions to reveal faults in the wiring harness. Observe the multimeter, ISAT scan tool or test lamp while carrying out this check.





Diagnostic Procedure.
1. Check the brake lights

- Check whether the brake lights come on when the brake pedal is depressed.

Do the brake lights work?
YES: Check the lead between pin 15 of the control module and crimped connection J32. Repair or replace the lead if necessary. Continue with point 2.
NO: Continue fault diagnosis in the electrical system, brake lights. Then carry out a final check in accordance with point 2.

2. Final check:

- Clear the diagnostic trouble code.
- Implementation of driving cycle: Drive the car at varying engine loads and rpm for 5 minutes.- Evaluation of driving cycle:
- Connect an ISAT scan tool.
- Select "READ ON/OFF".
- Select "BRAKE LIGHT SWITCH". The ISAT scan tool display should read "ON" when the brake pedal is depressed.

Does the display read "OFF"?
YES: Continue at "Before Replacing a Control Module". Component Tests and General Diagnostics
NO: The remedial measure taken was correct.