Brake Signal: Testing and Inspection

Brake Light Switch And Brake Pedal Switch Signals, Checking

For vehicles with cruise control system only!

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required
- VAG 1551/1552 Scan Tool using VAG 1551/3 Adaptor cable
- VAG 1598/22 Test Box
- Fluke 83 multimeter
- VW 1594 Adaptor kit
- Wiring diagram

- Connect VAG 1551/1552 Scan Tool. Refer to "Scan Tool Testing/VAG 1551 Scan Tool/Test Requirements and Work Procedures" Testing and Inspection
- Start engine and let idle
- Press 0 and 1 buttons to select "Engine Electronics" address word 01.

Indicated on display (example only)


06A906018AB Motronic M5.9.2 HS V06 ->
Coding 00000 WSC 00000


- Press -> button.

Indicated on display


Rapid data transfer HELP
Select function XX


- Press 0 and 8 buttons to select "Read Measuring Value Block" function 08.
- Press Q button to enter input.

Indicated on display


Read measuring value block HELP
Input Display group number XXX


- Press 0, 6 and 6 buttons to select "Display group 66"
- Press Q button to enter input.

Indicated on display


Read measuring value block 66 ->
1 2 3 4


- Observe value in Display field 2 (3rd and 4th digits from left)
- Specification: x x 0 0
- Fully depress brake pedal, observe values in Display field 2
- Specification: x x 1 1
- Press -> button.

Indicated on display


Rapid data transfer HELP
Select function XX


- Press 0 and 6 buttons to select "End output" function 06.
- Press Q button to enter input.
- Switch OFF ignition.







If specification not obtained
- Connect VAG 1598/22 Test Box to ECM harness connector.
- Check wiring for open circuit between Test Box and 4-pin harness connector using Wiring diagram.
- Terminal 3 + socket 48
- Terminal 4 + socket 47
Wire resistance: 1.5 Ohms maximum

If specification obtained
- Check wiring for open circuit between 4-pin harness connector terminals 1 + 2 and fuel pump relay using Wiring diagram.