Preliminary Information
The input and output signals of the convertible top control module -J256- can be checked using "Read Measuring Value Block" function 08 on the VAG1551 Scan Tool (ST). All input and output signals of the convertible top control module -J256- are scanned during convertible top movement.NOTES:
- If the convertible top cannot be unlocked at the center roof latch, open the convertible top using emergency activation of the convertible top unlatching lock. See "Unlocking Convertable Top" Unlocking Convertible Top From Front Roof Frame In an Emergency
- If the convertible top does not move automatically the input signals can still be checked using the scan tool Remove hydraulic pump fuse -S24- and load reduction relay -J59- (to deactivate the solenoid valves). Have a second person move the convertible top by hand. During top movement, input signals can be checked.
- The specified values are valid only during convertible top movement. If the movement is interrupted by releasing the operating switch, "0" is displayed for the convertible top operation switch -E137- and for the convertible top hydraulic pump -V118-.
- When checking output signals, check for the specified values only during top movement. When top movement is interrupted, additional solenoid valves for the holding function are triggered.
- If an actuator is not connected, a "1" is always displayed.
- Display values that change from the previous display are identified and explained alphabetically
- Pressing the -> button will exit the "Read Measuring Value Block" function. If this occurs, select "Read Measuring Value Block" function 08 once again.
- After checking the convertible top function sequence, check and erase DTC Memory.
Display value meanings:
Input signals
Value:
1 - switch closed = Ground (GND) potential
0 - switch open = voltage supply (B+) potential or open circuit in wiring
Output signals
Value:
1 - End stage switched on = Ground (GND) potential or open circuit in wiring
0 - End stage switched off = voltage supply (B+) potential
Test requirements
- Electrical consumers switched off
- Ignition switched on
- Check and erase Diagnostic Trouble Code (DTC) memory.
Indicated on display
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- to input "Read Measuring Value Block" function 08.
Indicated on display
Rapid data transfer Q
08 - Read Measuring Value Block
- Press -Q- button to enter input.
Indicated on display
Read Measuring Value Block HELP
Input display group number XXX
- Input desired display group number.
- For input signals, input display group number 001
- For output signals input display group number 002
NOTE: Display group number 001 is used as an example to show sequence.
- Press button -Q- twice and button -1- to input display group number 001.
Indicated on display
Read Measuring Value Block Q
Input display group number 001
- Press -Q- button to confirm input.
Indicated on display
Read Measuring value block 1 ->
1 2 3 4
NOTES:
- For display group numbers 001 and 002, the display group number will be shown without the "00."
- Press the -C- button before selecting additional display groups.
- With the printer switched on, the display shown is printed.
- Each time the PRINT button is pressed, the display shown is printed.
- Press -C- button.
Indicated on display
Read Measuring Value Block HELP
Input display group number XXX
- Input appropriate display group number and press -Q- but- ton to confirm input.
To end "Read Measuring Value Block" function 08:
- Press -> button.
Indicated on display
Rapid data transfer HELP
Select function XXX
- Check and erase DTC memory.
Test Procedure Information
- To ensure a constant and adequate voltage supply, start and run engine during the entire test sequence.
- If a complaint exists, start the test sequence one test step prior to where the convertible top begins malfunctioning.
- Check all input signals first.