Reading Measuring Value Block
Scan Tool VAG 1551Connecting / reading measuring value block
Notes:
^ A display group with 8 measured values is provided.
^ If the printer is switched on, the readout on the display is printed out on the log.
^ Observe test requirements.
^ The DTC Memory has been read and all DTCs displayed have been traced and repaired.
V.A.G. 1551 Scan Tool Connections:
Connect Scan Tool VAG 1551 to Data Link Connectors (DLC's) in relay carrier on left side of plenum chamber using harness VAG 1551/1
- Connect black connector to black DLC.
Note:
If no display appears, check voltage supply for black DLC. Refer to Data Link Connectors, Checking Wiring
V.A.G. 1551 Scan Tool Display:
Framed text appears on display;
* appears alternately
- Connect white connector to white DLC.
Note:
The blue plug is not required.
- Switch on ignition or start engine.
Notes:
^ The HELP button on VAG 1551 can be used to call up additional operating instructions.
^ The -> button is used to advance to the next step in the program.
^ Press button 1 for "Rapid data transfer" mode
Display appears as shown:
Rapid data transfer HELP
Enter address word XX
- Press buttons 0 and 3.
(03 enters address word "Brake electronics").
Display appears as shown:
Rapid data transfer Q
03 - Brake Electronics
- Confirm input with button Q
Control Module identification appears on display.
Display appears as shown:
4A0 907 379 D Brake Electronics
Notes:
^ The "D"suffix in the Control Module identification indicates an ABS Control Module with wheel speed outputs (e.g. vehicles with automatic transmission); the absence of a suffix indicates no wheel speed outputs.
^ Also check parts list for identification of appropriate ABS Control Module - J104.
If Display appears as shown:
Control Module does not answer!
OR
K-wire not switching to Ground/positive
HELP
OR
No signal from Control Module
- Press HELP button to print out a list of possible causes.
- Check wiring connection of Data Link Connectors, Refer to Data Link Connectors, Checking Wiring.
- Check power supply and Ground connection to Control Module - J104 using wiring diagram
- After correcting possible malfunctions enter address word 03 for brake electronics once again and verify with Q button.
If Display appears as shown:
Fault in communication buildup
- Refer to Data Link Connectors, Checking Wiring, to correct possible malfunctions.
- Press -> button.
Display appears as shown:
Rapid data transfer HELP
Select function XX
- Press button 0 and 8. This selects the function "Read measuring value block"
Display appears as shown:
Rapid data transfer Q
08 - Read measuring value block
- Acknowledge input with Q button
Display appears as shown:
Read measuring value block HELP
Enter display group number XX
- Press 0 button twice.
- Acknowledge input with Q button
Display appears as shown:
Read measuring value block
1 2 3 4 5 6 7 8
Notes:
^ The channels 1 to 4 indicate the wheel speed in km/h. This is calculated by the ABS Control Module - J104 per input from wheel speed sensor pulses.
If the vehicle is accelerated or moved evenly on a dry surface, a deviation between the readouts 1 to 4 of up to +/- 1 km/h is permissible.
If the difference is greater, check wheel speed sensors and rotors (Check Repair Group 45).
^ To check whether the sensors are correctly connected, turn the wheels by hand (block the other wheel of the driven axle to prevent it also turning). If the readings obtained indicate a malfunction, perform function test with ABS tester VAG 1710.
� Measuring Block Values:
^ Test table - reading measuring value block