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Home >> Volkswagen >> 1999 >> Passat Syncro Sedan (3B2) V6-2.8L (AHA) >> Repair and Diagnosis >> Brakes and Traction Control >> Antilock Brakes / Traction Control Systems >> Testing and Inspection >> Scan Tool Testing and Procedures >> On Board Diagnostics >> Output Diagnostic Test Mode

Output Diagnostic Test Mode



Output Diagnostic Test Mode (DTM) (VAG 1551 scan tool function 03)
The output diagnostic test mode is a part of the ABS electrical test. The ABS pump motor and the correct functioning of the hydraulic circuits (assignment of brake lines to wheel brake calipers; valve functions) can be checked for leaks or incorrect connections using the output diagnostic test mode.

Note:
- The vehicle must be raised until all wheels are free to turn. (2nd technician required to rotate wheels)
- The -C- button can be used to exit the test sequence at any time.
- The control period of the control elements is limited to 60 or 90 seconds. If the "=>" button is not operated within this time the output test will be terminated.
- 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 vacuum in 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:
Indicated on VAG 1551 scan tool display during the output diagnostic test mode:
(Example: left front wheel, FL)





IFL = Inlet valve Front Left
VBAT = Voltage Battery; Voltage at valve
OFL = Outlet valve Front Left
0V = 0 Volt; No voltage at valve
Locked/free = Wheel condition; must be checked by 2nd mechanic





Hydr-P = Hydraulic Pump
- Correct VAG 1551 scan tool.
- Switch on ignition.
- Press button -1- for "Rapid data transfer" operating mode.
- Select "Brake Electronics" address word 03. VAG 1551 Scan Tool Connecting and Selecting Function





Indicated on display
- Confirm input with -Q- button.

Note: Three warning tones are audible during the interrogation of the control module identification.

- Read control module version in VAG 1551 display.
- Press => button.





Indicated on display
- Press buttons -0- and -3- to select "Output diagnostic test mode" function 03.





Indicated on display
- Confirm entry with -Q- button.

Note:
- During the next work sequence the ABS warning light -K47- flashes 4 times per second and the warning light for brake system -K118- flashes 3 times per second.
- Vehicles with a navigation system: only the ABS warning light -K47- flashes 4 times per second.





Indicated on display

Note: The designation "ABS hydraulic pump -V64-" refers to the described "ABS return flow pump -V39-" Both designations refer to the same component.
- ABS return flow pump -N39- must run.

- Press => button.





Indicated on display
- Operate brake pedal.
- Press => button.





Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel does not lock, there is a possibility that there is a malfunction in the mechanical/hydraulic part of the brake system.

- Press => button.





Indicated on display
- Press => button.
- ABS return flow pump -V39- must run.
- Brake pedal must not give.
If the brake pedal gives, there is a malfunction in the hydraulic unit. In this case the hydraulic unit with control module must be replaced,





Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel locks there is a possibility that the brake lines to the wheel calipers/cylinders have been interchanged.

- Press => button.
- ABS return flow pump -V39- must no longer run.





Indicated on display
- Press => button.
- Brake pedal must give noticeably
If the brake pedal does not give, there is a malfunction in the hydraulic unit. In this case the hydraulic unit with control module must be replaced.





Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel does not lock, there is a possibility that there is a malfunction in the mechanical/hydraulic part of the brake system.

- Press => button.





Indicated on display
- Remove foot from brake pedal,
- Press => button.





Indicated on display
- Operate brake pedal.
- Press => button.





Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel does not lock, there is a possibility that there is a malfunction in the mechanical/hydraulic part of the brake system.

- Press => button.





Indicated on display
- Press => button.
- ABS return flow pump -V39- must run.
- Brake pedal must not give
If the brake pedal gives, there is a malfunction in the hydraulic unit. In this case the hydraulic unit with control module must be replaced.






Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel locks there is a possibility that the brake lines to the wheel calipers/cylinders have been interchanged.

- Press => button.
- ABS return flow pump -V39- must no longer run.





Indicated on display
- Press => button.
- Brake pedal must give perceptibly
If the brake pedal does not give, there is a malfunction in the hydraulic unit. In this case the hydraulic unit with the control module must be replaced.





Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel does not lock, there is a possibility that there is a malfunction in the mechanical/hydraulic part of the brake system.

- Press => button.





Indicated on display
- Remove foot from brake pedal.
- Press => button.





Indicated on display
- Operate brake pedal.
- Press => button.





Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel does not lock, there is a possibility that there is a malfunction in the mechanical/hydraulic part of the brake system.

- Press => button.





Indicated on display
- Press => button.
- ABS return flow pump -V39- must run.
- Brake pedal must not give
If the brake pedal gives, there is a malfunction in the hydraulic unit. In this case the hydraulic unit with control module must be replaced.





Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel locks there is a possibility that the brake lines to the wheel calipers/cylinders have been interchanged.

- Press => button.
- ABS return flow pump -V39- must no longer run.





Indicated on display
- Press => button.
- Brake pedal must give perceptibly
If the brake pedal does not give, there is a malfunction in the hydraulic unit. In this case the hydraulic unit with the control module must be replaced.





Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel does not lock, there is a possibility that there is a malfunction in the mechanical/hydraulic part of the brake system.

- Press => button.





Indicated on display
- Remove foot from brake pedal.
- Press => button.





Indicated on display
- Operate brake pedal.
- Press => button.





Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel does not lock, there is a possibility that there is a malfunction in the mechanical/hydraulic part of the brake system.

- Press => button.





Indicated on display
- Press => button.
- ABS return flow pump -V39- must run.
- Brake pedal must not give
If the brake pedal gives, there is a malfunction in the hydraulic unit. In this case the hydraulic unit with control module must be replaced.





Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel locks there is a possibility that the brake lines to the wheel calipers/cylinders have been interchanged.

- Press => button.
- ABS return flow pump -V39- must no longer run.





Indicated on display
- Press => button.
- Brake pedal must give perceptibly
If the brake pedal does not give, there is a malfunction in the hydraulic unit. In this case the hydraulic unit with the control module must be replaced.





Indicated on display
- Indicate to 2nd technician which wheel requires turning by hand.

Note: If the wheel does not lock, there is a possibility that there is a malfunction in the mechanical/hydraulic part of the brake system.

- Press => button.





Indicated on display
- Remove foot from brake pedal.
- Press => button.





Indicated on display (vehicles with EDL)
- Press => button.





Indicated on display
- Press => button.

Note:
- The ABS warning light -K47- and the warning light for brake system K118- go out and the Output Diagnostic Test Mode is completed.
- Only the ABS warning light -K47- goes out on vehicles with a navigation system.

- Press => button.





Indicated on display

Note:
- If the ABS warning light does not go out then there is a malfunction in the system
- Adhere exactly to test sequence: First interrogate the Diagnostic Trouble Code (DTC) memory, then erase

- End output (Function 06). DTC Memory, Erasing and Ending Output

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