Reading Measured Value Block
Measured value block, reading
Note: All functions, which could previously be performed V.A.G 1551 can also be performed with the tester VAS 5051.
The control module can transfer a considerable amount of test data. This test data delivers information on the operational condition of the system and/or sensors connected to it. In many cases the transferred test data supports troubleshooting and repair. The test data has been summarized into single display groups because all the information cannot be evaluated at the same time. The information can be selected via display group numbers.
Safety precautions
Observe following if test and measuring instruments are required during a test drive:
^ Test and measuring instruments must be secured to rear seat and operated by a 2nd person from this location.
WARNING! When test and measuring instruments are operated from the front passenger seat there is a danger that the person sitting there could be injured in an accident when the airbag is triggered.
^ Connect V.A.G 1551 Scan Tool and select brake electronics with ignition switched on (address word 03).
Indicated on display
^ Press keys O and 8. (The function "Read measured value block" is initiated with 08.)
Indicated on display:
^ Confirm entry with key Q.
Indicated on display
^ Enter display group number = List of selectable display group numbers.
List of selectable display group numbers
1) Vehicles with automatic transmission only.
Test sequence and test tables with measured values
Checking speed sensor allocation
Display group number 001
Press keys 0, 0 and 1.
^ Confirm entry with key Q.
There are always 4 display zones -arrows- in the measured value block. Decoding the individual values in display zones 1 to 4 can be read from the following tables.
Indicated on display (vehicle stationary)
Press C key for the next display group number entry.
If the (arrow) key is pressed, keys O and 8 for work sequence "Read measured value block" must be pressed again afterwards to regain entry.
Note: For display group number 001 remember:
The actual wheel speeds are displayed. They serve to check the speed sensor allocation to the wheel. (The vehicle must be raised and the wheel must be rotated by hand by a 2nd mechanic).
Checking speed sensor
Display group number 002
^ Press keys 0, 0 and 2.
^ Confirm entry with key Q.
There are always 4 display zones -arrows- in the measured value block. Decoding the individual values in display zones 1 to 4 can be read from the following tables.
Indicated on display (Vehicle stationary)
Press C key for the next display group number entry.
If the (arrow) key is pressed, keys O and 8 for work sequence "Read measured value block" must be pressed again afterwards to regain entry.
Note: For display group number 002 remember:
^ The reading of measured value blocks in display group number 002 must be undertaken when driving off slowly. Then the control module -J104- will store the first usable voltage signals provided by the speed sensors and display these as a fixed value in the measured value block.
1) If the deviations in display zones 1 and 2 are greater than 6 km/h (approximately 3.75 mph), the following malfunctions may be present:
2) If the deviations in display zones 3 and 4 are greater than 2 km/h (approximately 1.25 mph), the following malfunctions may be present:
^ Air gap between speed sensor and rotor may be too big.
^ Check that speed sensor is screwed correctly to wheel bearing housing.
^ Speed sensor or rotor exterior damaged.
^ Change damaged component.
Checking brake light switches
Display group number 003
^ Press keys 0, 0 and 3
^ Confirm entry with key Q.
There are always 4 display zones -arrows- in the measured value block. Decoding the individual values in display zones 1 to 4 can be read from the following tables.
Indicated on display (vehicle stationary)
Press C key for the next display group number entry.
If the (arrow) key is pressed, keys O and 8 for work sequence "Read measured value block" must be pressed again afterwards to regain entry.
Checking data bus wiring
Display group number 125
^ Press keys 1, 2 and 5
^ Confirm entry with key Q.
There are always 4 display zones -arrows- in the measured value block. Decoding the individual values in display zones 1 to 4 can be read from the following tables.
Indicated on display (vehicle stationary)
Press C key for the next display group number entry.
If the (arrow) key is pressed, keys 0 and 8 for work sequence "Read measured value block" must be pressed again afterwards to regain entry.
^ 1) Only for vehicles with automatic transmission
1) Vehicles with automatic transmission only.
^ Incorrect transmission control module or incorrect transmission control module coding.
^ Transmission control module faulty.
2) Data bus connection is interrupted or data bus wires are interchanged.