Brake Light Switch and Brake Pedal Switch Signal, Checking
Signal From Brake Light Switch and Brake Pedal Switch
Special tools equipment
- V.A.G 1551 Scan Tool or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
- Test box V.A.G 1598/31
- Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
- Adapter set V.A.G 1594
- Wiring diagram
Check conditions
- All fuses must be OK.
- Battery voltage must be at least 11.5 V.
- All electrical consumers, e.g. lights and rear window defroster must be switched off
Test sequence
- Connect V.A.G 1551 Scan Tool ((V.A.G 1552). Switch ignition on and select engine control module with "Address word" 01. (Connecting scan tool and selecting engine control module). Refer to "VAG1551 Scan Tool Tools and Equipment
Indicated on display
Rapid data transfer HELP
Select function XX
- Press keys 0 and 8 for function "Read measured value block" and confirm entry with Q key.
Indicated on display
Read measured value block HELP
Input display group number XXX
- Press keys 0, 6 and 6 for "display group 66" and confirm with Q key.
Indicated on display
Read measured value block 66 ->
1 2 3 4
Only engine code AWP
- Observe display in display zone 2: (1st and 2nd positions from right) Specification: x x x x x x 0 0
- Depress brake pedal fully and observe display in display zone 2. Specification: x x x x x x 1 1
Only engine code AWW
- Observe display in display zone 2: (3rd and 4th positions from left) Specification: x x 0 0
- Depress brake pedal fully and observe display in display zone 2. Specification: x x 1 1
Continuation for all engines
- Press -> key.
- Press keys 0 and 6 for "End output" function and confirm input with Q key.
- Switch ignition off.
If the specification is not obtained:
- Remove shelf on driver's side:
- Pull connector off brake light/brake pedal switch
- Connect multimeter to measure resistance between contacts 1 and 4.
Specification: infinity Ohm (no continuity)
- Depress brake pedal.
Specification: approx. 0 Ohm
- Connect multimeter to measure resistance between contacts 2 and 3.
Specification: approx. 0 Ohm
- Depress brake pedal.
Specification: infinity Ohm (no continuity)
If the specifications are not attained:
- Replace brake light/brake pedal switch.
- Check DTC Memory, if necessary, repair any malfunctions and then Erase DTC Memory, Checking and Erasing DTC Memory. Refer to "Displaying and Reading Trouble Codes/With Manufacture Scan Tool/Check DTC Memory (Function 02)" Testing and Inspection
- Read readiness code. If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again: Refer to "Monitors, Trips and/or Drive Cycle/ Reading Readiness Code" Testing and Inspection
Engine code AWW, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code" Testing and Inspection
Engine code AWP, Refer to "Monitors, Trips and/or Drive Cycle/Generating Readiness Code" Testing and Inspection
If the specifications are obtained:
- Connect multimeter to measure voltage between contact 1 and earth.
Specification: at least 11.5 V
- Switch ignition on.
- Connect multimeter to measure voltage between contact 2 and earth.
Specification: at least 11.5 V
If the specifications are not obtained:
- Check wire between 4-pin connector contact 1 and main fuse/contact 2 and central electrics using wiring diagram.
If the specification is obtained:
- Connect test box V.A.G 1598/31 to control module wiring harness. Engine control module remains disconnected.
- Check wiring for open circuit between test box and 4-pin connector using wiring diagram.
Contact 3+socket 55
Contact 4+socket 56
Wire resistance: Max. 1.5 Ohm
- Additionally check wires for short to one another.
- Additionally check wiring for short to battery positive or Ground.
If no malfunction is detected in the wiring:
- Replace engine control module.