DTC 00741

DTC code 00741:
Brake Pedal Position Monitoring
Questionable Signal

For safety reasons, Throttle Position sensor G79 together with Brake Light Switch F and Brake Pedal Switch F47 signals are monitored by the Engine Control Module (ECM). If the Accelerator Pedal is held at a constant position and brakes are applied, engine rpm will immediately drop to an idle. Incorrectly adjusted switches can cause unrequired regulating action.

Special Tools, Testers And Auxiliary Items:
- VAG 1598/18 Test Box adaptor
- Fluke 83 Multimeter or equivalent
- VW 1594 Adaptor kit
- Wiring diagram

Work Sequence:
Display will appear as shown:

Rapid data transfer HELP
Select function XX

- Press 0 and 6 buttons to select Function 06 "End data transfer"
- Press Q button to enter input
- Switch OFF ignition
- Switch ignition back ON
- Press 0 and 1 buttons to select address word 01: "Engine electronics"
Display will appear as shown:

Rapid data transfer HELP
Select function XX

- Press 0 and 8 buttons to select Function 08 "Read measuring value block"
- Press Q button to enter input
Display will appear as shown:

Read measuring value block HELP
Input display group number XX

- Press 0 and 6 buttons to select "display group 06"
- Press Q button to enter input
- Observe display in channel 2
Display will appear as shown:

Read measuring value block 6 -->
0km/h 0 0 0 00000 255

Specification: 0 0 0

- Slowly operate brake pedal
Display will appear as shown:

Read measuring value block 6 -->
0km/h 0 1 1 00000 255

Specification: 0 1 1
(both displays must change from 0 to 1 simultaneously)
- Center display = Brake Pedal switch F47
- Right hand display = Brake Light switch F

If displays do not change together:
- Adjust contact point for Brake Pedal Switch F47 by turning switch
- Adjust contact point for Brake Light Switch F by moving plunger

If center display does not change:
- Press -> button
- Press 0 and 6 buttons to select Function 06 "End data transfer"
- Press Q button to enter input
- Switch OFF ignition





- Disconnect Brake Pedal Switch F47 -1- harness connector
- Measure resistance between switch terminals
Specification:
Brake pedal not depressed: less than 10 ohm
Brake pedal depressed: infinite ohm

If specified resistance not obtained:
- Replace Brake Pedal Switch F47





If specified resistance obtained:
- Connect VAG 1598/18 Test Box adaptor to ECM wiring harness





- Check wiring for open circuit between VAG 1598/18 Test Box adaptor and harness connector using wiring diagram:
Terminal 1 + socket 20
Terminal 2 + socket 33
Wire resistance: 1.5 ohm maximum

- Check for shorting between wires
Specification: infinite ohm

If right-hand display does not change:
- Press -> button
- Press 0 and 6 buttons to select Function 06 "End data transfer"
- Press Q button to enter input
- Switch OFF ignition
- Switch multimeter to voltage range and connect between VAG 1598/18 Test Box adaptor sockets 44 + 1
- Observe voltage indicated
Specification:
Brake pedal not depressed: 0 Volts.
Brake pedal depressed: approx. battery voltage.

If no voltage displayed:
- Check brake light function

If brake light OK:
- Check wiring for open or short circuit to Brake Light Switch F using wiring diagram

If brake light not OK:
- Replace Brake Light Switch F