Output Diagnostic Test Mode (DTM) (Function 03)
Output Diagnostic Test Mode (DTM) (function 03)
The pump motor can be checked via output Diagnostic Test Mode (DTM), and the correct function of the hydraulic circuit (allocation of brake pressure lines to wheel brakes and function of valves) can be checked for mix-ups and leaks.
Note:
^ The vehicle must be raised until all wheels are free to turn. ( 2. technician required for turning wheels)
^ Test sequence can always be exited via the -C- button on the tester.
^ Activation time of actuators is limited to 60 or 90 seconds. The actuator test will be terminated if the " (arrow) button" is not pressed within this period.
^ Pressing the brake pedal repeatedly relieves the vacuum in the brake booster. This means that more pressure must be applied to the brake pedal in order to achieve the same fluid pressure in the brake system as is achieved with vacuum.
^ With the vacuum released from the brake booster, it is possible that the wheels will not lock Refer to start engine in order to build up vacuum in the brake booster.
Example:
VAG1551 Display during output Diagnostic Test Mode (DTM)
(e.g. front left wheels fl)
IfI = Inlet valve, front left
B+ = Battery Positive Voltage (B+), there is voltage at valve
0fl = Outlet valve, front left
0V = 0 volts; no voltage at valve
locked/ free = wheel condition, must be checked by 2nd technician
^ Connect VAG 1 551 Scan Tool (ST).
^ Switch on ignition.
^ Press button -1- to select "Rapid data transfer" operating mode 01.
^ Select control module for brake electronics (address word 03), Refer to VAG1551 Scan Tool (ST), Connecting and Selecting Functions
Indicated on display
^ Press -Q- button to confirm input.
Note: Three warning tones will sound while the control module identification is checked.
^ The control module version is shown on the display of the VAG1551 Scan Tool (ST).
^ Press (arrow) button.
Indicated on display
^ Press buttons -0- and -3-.
Indicated on display
^ Press -Q- button to confirm input.
Note: During the next few work steps, the ABS warning light -K47- will blink 4 times per second and the warning light for brake system -K118- will blink 3 times per second.
For vehicles with navigation system, only the ABS warning light -K47- 4- will blink, 4 times per second.
Indicated on display
Note: "ABS hydraulic pump -V64-" is used to refer to "ABS return flow pump -V39-". Both terms refer to the same component.
ABS return flow pump -V39- should start running.
^ Press (arrow) button.
Indicated on display
^ Operate brake pedal.
^ Press (arrow) button.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel does not lock, it is possible that there is a malfunction in the mechanical/hydraulic part of the brake system.
^ Press (arrow) button.
Indicated on display
^ Press (arrow) button.
ABS return flow pump -V39- should start running.
Brake pedal must not give.
If brake pedal gives, there is a malfunction in the hydraulic unit. If this is the case, the hydraulic unit with the control module must be replaced.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel locks, it is possible that the brake pressure lines to the wheel brakes have been mixed up.
^ Press (arrow) button.
ABS return flow pump -V39- will stop running.
Indicated on display
^ Press (arrow) button.
Brake pedal must give noticeably.
If brake pedal does not give, there is a malfunction in the hydraulic unit. If this is the case, the hydraulic unit with the control module must be replaced.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel does not lock, it is possible that there is a malfunction in the mechanical/hydraulic part of the brake system.
^ Press (arrow) button.
Indicated on display
^ Remove foot from brake pedal.
^ Press (arrow) button.
Indicated on display
^ Operate brake pedal.
^ Press (arrow) button.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel does not lock, it is possible that there is a malfunction in the mechanical/hydraulic part of the brake system.
^ Press (arrow) button.
Indicated on display
^ Press (arrow) button.
ABS return flow pump -V39- should start running.
Brake pedal must not give.
If brake pedal gives, there is a malfunction in the hydraulic unit. If this is the case, the hydraulic unit with the control module must be replaced.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel locks, it is possible that the brake pressure lines to the wheel brakes have been mixed up.
^ Press (arrow) button.
ABS return flow pump -V39- will stop running.
Indicated on display
^ Press (arrow) button.
Brake pedal must give noticeably.
If brake pedal does not give, there is a malfunction in the hydraulic unit. If this is the case, the hydraulic unit with the control module must be replaced.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel does not lock, it is possible that there is a malfunction in the mechanical/hydraulic part of the brake system.
^ Press (arrow) button.
Indicated on display
^ Remove foot from brake pedal.
^ Press (arrow) button.
Indicated on display
^ Operate brake pedal.
^ Press (arrow) button.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel does not lock, it is possible that there is a malfunction in the mechanical/hydraulic part of the brake system.
^ Press (arrow) button.
Indicated on display
^ Press (arrow) button.
ABS return flow pump -V39- should start running.
Brake pedal must not give.
If brake pedal gives, there is a malfunction in the hydraulic unit. If this is the case, the hydraulic unit with the control module must be replaced.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel locks, it is possible that the brake pressure lines to the wheel brakes have been mixed up.
^ Press (arrow) button.
ABS return flow pump -V39- will stop running.
Indicated on display
^ Press (arrow) button.
Brake pedal must give noticeably.
If brake pedal does not give, there is a malfunction in the hydraulic unit. If this is the case, the hydraulic unit with the control module must be replaced.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel does not lock, it is possible that there is a malfunction in the mechanical/hydraulic part of the brake system.
^ Press (arrow) button.
Indicated on display
^ Remove foot from brake pedal.
^ Press (arrow) button.
Indicated on display
^ Operate brake pedal.
^ Press (arrow) button.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel does not lock, it is possible that there is a malfunction in the mechanical/hydraulic part of the brake system.
^ Press (arrow) button.
Indicated on display
^ Press (arrow) button.
ABS return flow pump -V39- should start running.
Brake pedal must not give.
If brake pedal gives, there is a malfunction in the hydraulic unit. If this is the case, the hydraulic unit with the control module must be replaced.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel locks, it is possible that the brake pressure lines to the wheel brakes have been mixed up.
^ Press (arrow) button.
ABS return flow pump -V39- will stop running.
Indicated on display
^ Press (arrow) button.
Brake pedal must give noticeably.
If brake pedal does not give, there is a malfunction in the hydraulic unit. If this is the case, the hydraulic unit with the control module must be replaced.
Indicated on display
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel does not lock, it is possible that there is a malfunction in the mechanical/hydraulic part of the brake system.
^ Press (arrow) button.
Indicated on display
^ Remove foot from brake pedal.
^ Press (arrow) button.
Indicated on display: (for vehicles with EDL)
^ Instruct 2nd technician to turn the affected wheel by hand.
Note: If wheel does not lock, it is possible that there is a malfunction in the mechanical/hydraulic part of the brake system.
^ Press (arrow) button.
Indicated on display
^ Press (arrow) button.
Note: The ABS warning light -K47- and the warning light for brake system -K118- switch off. The output Diagnostic Test Mode is completed.
For vehicles with navigation system, only the ABS warning light -K47- switches off.
^ Press (arrow) button.
Indicated on display
Note:
^ If the ABS warning light does not go out, there is a malfunction in the system.
^ Follow test sequence exactly: First Check DTC Memory, then erase it.
^ End Output (function 06), Refer to Erase DTC Memory (Function 05), End Output (Function 06)