Read Measuring Value Block (Function 08)

Read Measuring Value Block (function 08)
The control module can transmit numerous measured values. These measured values provide information about the operational status of the system and the sensors connected to it. In many cases the data supplied can be used to troubleshoot and repair malfunctions. Because these measured values cannot all be evaluated simultaneously, they are organized into individual display groups that can be selected via display group numbers.
^ Connect VAG1551 Scan Tool (ST), enter address word "03 Brake Electronics" and continue until "Select function XX" is indicated on display.

Indicated on display:
^ Press buttons -0- and -8-. This selects "Read Measuring Value Block" function 08.

Indicated on display:
^ Press -Q- button to confirm input.

Indicated on display:
^ Enter display group number, Overview of selectable display group numbers.

Overview of selectable display group numbers

Test sequence and test tables with measured values
Display group number 001
^ Press buttons -0-, -0- and -1-.
^ Press -Q- button to confirm input.

^ Measuring value block always has 4 display fields (arrows). Values 1 to 4 in the individual display fields can be interpreted according to the following test table.

Use button -1- to select the next lower display group number in sequence; use button -3- to select the next higher display group number.
Press the (arrow) button to manually enter the next display group number. After this, the work sequence "Read Measuring Value Block" must be re-initiated using buttons -0- and -8-.

Notes:
For display group number 001:
The current wheel speeds are indicated. This is useful for checking wheel speed sensor allocation by wheel. (Vehicle must be raised and a second technician must turn wheel by hand)

1) On Board Diagnostic (OBD) will be terminated by the ABS control module -J104- if road speed exceeds 19 km/h.

Display group number 002

Indicated on display:
^ Press buttons -0-, -0- and -2-.
^ Press -Q- button to confirm input.

Display group number 003
Measuring value block display group 003 should be read with engine running

Indicated on display:
^ Press buttons -0-, -0- and -3-.
^ Press -Q- button to confirm input.

^ Measuring value block always has 4 display fields (arrows). Values 1 to 4 in the individual display fields can be interpreted according to the following test table.

Use button -1- to select the next lower display group number in sequence; use button -3- to select the next higher display group number.
Press the (arrow) button to manually enter the next display group number. After this, the work sequence "Read Measuring Value Block" must be re-initiated using buttons -0- and -8-.

Notes:
For display group number 003:
Measuring value block display group 003 should be read with engine running.

Display group number 004

Indicated on display:
^ Press buttons -0-, -0- and -4-.
^ Press -Q- button to confirm input.

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.

Notes:
^ 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 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 wheel, fl)

Ifl = 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

Hydr-P = Hydraulic pump

^ Connect VAG1551 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).

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
^ Remove foot from brake pedal.
^ Press (arrow) button.

Indicated on display
^ Operate brake pedal.
^ Press (arrow) button.

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

Indicated on display
^ Operate brake pedal.
^ 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
^ 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.

Notes: 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

Notes:
^ 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).