With Manufacturer's Scan Tool
Brake Light Switch and Brake Pedal Switch Signal, Checking
Special tools, workshop equipment, testers, measuring instruments and auxiliary items required
- VAG 1551 Scan tool (or VAG 1552) with VAG 1551/3 adapter cable
NOTE: All functions which could previously be performed with VAG 1551/1552 can also be performed with the VAS 5051.
- VAG 1526 Hand multimeter or VAG 1715 multimeter
- VAG 1594 Adapter set
- VAG 1598/31 test box
- Electrical Wiring Diagrams
Test prerequisites
- The fuses must be OK.
- The battery voltage must be at least 11.5 V.
- All electrical accessories, e.g. lights and rear window heating must be switched off.
- If the vehicle is equipped with air conditioning, it must be turned off.
- Selector lever must be in position "P" or "N" on vehicles with an automatic transmission.
Test sequence
- Connect VAG 1551 Scan tool (or VAG 1552). Then switch ignition on and select Motronic Engine Control Module (ECM) -J220- with the "Address word" 01. ((VAG 1551 and Motronic Engine Control Module (ECM) -J220-, connecting and selecting).
[1][2][3]Connecting VAG 1551 Scan Tool
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- for function "Read measured value (data) block" and confirm entry with -Q- button.
Indicated on display:
Read measured value block
Input display group number XXX
- Press buttons -0-, -6- and -6- for "Display group number 66" and confirm entry with -Q- button.
Indicated on display: (1 to 4 = display zones)
Read measured value block 66 ->
1 2 3 4
- Observe display in display zone 2: (7th and 8th positions from left)
Specification: xxxxxx00
- Depress brake pedal and observe display in display zone 2.
Specification: xxxxxx11
- Press the -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with the -Q- button.
- Switch off ignition.
If the specifications are not obtained:
- Remove cover in footwell (driver's side).
- Pull 4-pin connector off Brake Light Switch -F-and Brake Pedal Switch (cruise control/Diesel Direct Fuel Injection -F47-.
- Measure resistance between terminals 1 and 4 of switch.
Specification
Brake pedal not depressed: infinity ohms
Brake pedal depressed: max. 1.5 ohms
- Measure resistance between terminals 2 and 3 of switch.
Specification
Brake pedal not depressed: max. 1.5 ohms
Brake pedal depressed: infinity ohms
If the specifications are not obtained:
- Replace Brake Light Switch -F-and Brake Pedal Switch (cruise control/Diesel Direct Fuel Injection -F47-.
- Check DTC memory, repair malfunctions if necessary and then erase DTC memory.
Reading Diagnostic Trouble Codes
- Read readiness code. If the DTC memory has been erased or the Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive (B+), the readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes
If the specifications are obtained:
- Connect multimeter to measure voltage between terminal 1 and ground (GND).
Specification: at least 11.5 V
If the specification is not obtained:
- Check wiring connections to fuse holder for open circuit referring to Electrical Wiring Diagrams.
Wire resistance: max. 1.5 ohms
If the specification is obtained:
- Connect the multimeter to measure voltage between terminal 2 and ground (GND).
- Switch on ignition.
Specification: at least 11.5 V
- Switch off ignition.
If the specification is not obtained:
- Check wire for open circuit between 4-pin connector terminal 2 and Fuel Pump (FP) Relay -J17- referring to Electrical Wiring Diagrams.
Wire resistance: max. 1.5 ohms
If the specification is obtained:
- Remove wiper arms and cowl panel:
- Connect VAG 1598/31 test box to control module wiring harness. The Motronic Engine Control Module (ECM) -J220- remains disconnected.
- Check wiring for open circuit between test box and 4-pin connector referring to Electrical Wiring Diagrams.
Terminal 3 and socket 55
Terminal 4 and socket 56
Wire resistance: max. 1.5 ohms
- Additionally check wiring for short to one another, to vehicle ground (GND) and to battery positive.
Specification: infinity ohms
If there is no Diagnostic Trouble Code (DTC) in the wiring and the resistance measurement values are OK.:
- Replace Motronic Engine Control Module (ECM) -J220-.
- Check DTC memory, repair malfunctions if necessary and then erase DTC memory.
Reading Diagnostic Trouble Codes
- Erase learned values and adapt Motronic Engine Control Module (ECM) -J220- again.
- Read readiness code. If the DTC memory has been erased or the Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive (B+), the readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes