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Function 03-Output Diagnostic Test Mode



Output Diagnostic Test Mode (DTM) (VAG 1551 Scan Tool Function 03)

The output diagnostic test mode is part of the ABS electrical test. The ABS pump motor and the functioning of the hydraulic circuits (brake line connections to wheel brake calipers; valve functions) can be checked for leaks or for incorrect connections using the output diagnostic test mode.

NOTE:
^ The vehicle must be raised until all wheels are free to turn. (second technician required to rotate wheels).
^ The -C- button can be used to exit the test sequence at any time.
^ After depressing the brake pedal several times the vacuum in the brake servo will be exhausted, therefore more pressure must be applied to the brake pedal in order to attain the same fluid pressure in brake system as that attained with vacuum.
^ When the vacuum for the brake servo is exhausted it can lead to a situation in which the wheels do not lock; start the engine and build-up vacuum in the brake servo.

EXAMPLE (left-front wheel, FL):

- Indicated on display.

Output diagnostic test mode
IFL:VBAT OFL:OV Wheel FL locked

WHERE;
- IFL = IInlet valve Front Left
- VBAT = Voltage BATtery; voltage at valve.
- 0FL = 0utlet valve Front Left
- 0V = 0 Volts; no voltage at valve.
- Locked/free = Wheel condition.

Caution! Wheel condition (locked or free) must be checked and verified by a second technician.

- Indicated on display:

Output diagnostic test mode
EDL valves/Hyd-P:VBAT Wheel FL/FR locked

WHERE;
- Hydr-P = Hydraulic Pump

EXAMPLE ENDS

1. Release parking brake.
2. Connect VAG 1551 scan tool, switch ignition on, and select "Brake Electronics" address word 03.

- Indicated on display:

Rapid data transfer HELP
Select function XX

3. Press buttons -O- and -3- to select "Output Diagnostic Test Mode" function 03.

- Indicated on display:

Rapid data transfer Q
03-Output Diagnostic Test Mode

4. Press -Q- button to confirm input.
^ ABS hydraulic pump -V64- must run.

NOTE: During the work sequence that follows, the ABS warning light flashes 2 times per second and the brake system warning flashes 4 times per second.

- Indicated on display:

Output diagnostic test mode
ABS hydraulic pump -V64

5. Press right ARROW button within next 60 seconds.

- Indicated on display:

Diagnostic test mode
Operate brakes

6. Press brake pedal and hold.
7. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
IFL:0V OFL:OV Wheel FL locked

8. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
IFL:VBAT OFL:0V Wheel FL locked

9. Press right ARROW button.
^ ABS hydraulic pump -V64- must run.
^ Brake pedal must not give.

- Indicated on display:

Output diagnostic test mode
IFL:VBAT OFL:VBAT Wheel FL free

10. Press right ARROW button.
^ ABS hydraulic Pump -V64- stops running.

- Indicated on display:

Output diagnostic test mode
IFL:VBAT OFL:0V Wheel FL free

11. Press right ARROW button.
^ Brake pedal must give perceptibly.

- Indicated on display:

Output diagnostic test mode
IFL:0V OFL:0V Wheel FL locked

12. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
Release brakes

13. Release brake pedal.
14. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
Operate brakes

15. Press brake pedal and hold.
16. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
IFL:0V OFL:0V Wheel FR locked

17. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
IFL:VBAT OFL:0V Wheel FR locked

^ ABS hydraulic pump -V64- must run.
^ Brake pedal must not give.

- Indicated on display:

Output diagnostic test mode
IFR:VBAT OFR:VBAT Wheel FR free

18 Press right ARROW button.
^ ABS hydraulic pump -V64- stops running.

Indicated on display:

Output diagnostic test mode
IFR:VBAT OFR:0V Wheel FR free

19. Press right ARROW button.
^ Brake pedal must give perceptibly.

- Indicated on display:

Output diagnostic test mode
IFR:0V OFR:0V Wheel FR locked

20. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
Release brakes

21. Release brake pedal.
22. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
Operate brakes

23. Press brake pedal and hold.
24. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
IRL:0V ORL:0V Wheel RL locked

25. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
IRL:VBAT ORL:0V Wheel RL locked

26. Press right ARROW button.
^ ABS hydraulic pump -V64- must run.
^ Brake pedal must not give.

- Indicated on display:

Output diagnostic test mode
IRL:VBAT ORL:VBAT Wheel RL free

27. Press right ARROW button.
^ ABS hydraulic pump -V64- stops running.

Indicated on display:

Output diagnostic test mode
IRL:VBAT ORL:0V Wheel RL free

28. Press right ARROW button.
^ Brake pedal must give perceptibly.

- Indicated on display:

Output diagnostic test mode
IRL:0V ORL:0V Wheel RL locked

29. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
Release brakes

30. Release brake pedal.
31. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
Operate brakes

32. Press brake pedal and hold.
33. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
IRR:0V ORR:0V Wheel RR locked

34. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
IRR:VBAT ORR:0V Wheel RR locked

35. Press right ARROW button.
^ ABS hydraulic pump -V64- must run
^ Brake pedal must not give.

- Indicated on display:

Output diagnostic test mode
IRR:VBAT ORR:VBAT Wheel RR free


36. Press right ARROW button.
^ ABS hydraulic Dump -V64- stops running.

- Indicated on display:

Output diagnostic test mode
IRR:VBAT ORR:OV Wheel RR free

37. Press right ARROW button.
^ Brake pedal must give perceptibly.

- Indicated on display:

Output diagnostic test mode
IRR:0V ORR:0V Wheel RR locked

38. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
Release brakes

39. Release brake pedal.
40. Press right ARROW button.

- Indicated on display:

Output diagnostic test mode
EDL valves/Hyd-P:VBAT Wheel FL/FR locked

41. Press right ARROW button.
^ ABS warning light and brake system warning light go out.

- Indicated on display:

Function is unknown or
cannot be carried out at the moment

42. The output diagnostic test mode is completed.
43. Press right ARROW button.

- Indicated on display:

Rapid data transfer HELP
Select function XX

NOTE:
^ If the ABS warning light does not go out then there is a malfunction in the system.
^ Adhere exactly to the test sequence: First check DTC memory then erase.
44. Select function 06-End Output. Function 06-End Output
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