Component Tests and General Diagnostics

Cruise control system, checking

Requirements
- VAS5051 tester connected and vehicle On Board Diagnostic (OBD) selected, Refer to "Scan Tool Testing/Scan Tool Testing and Initial Checks/VAS5051 Tester, Connecting" under "Headlamp" Testing and Inspection
- Engine running at idle:

Initiating "Read Measuring Value Block"


Display on VAS5051:







- Press selection -1- of vehicle system "01 - Engine electronics".
- Wait until the next indication appears on display.


Display on VAS5051:







1 - Control module identification of Engine Control Module (ECM).
2 - Control module identification of immobilizer
- Click on -> button


Display on VAS5051:







- Select diagnostic function "08 - read measured value block" in selection -1-


Display on VAS5051:







1 - Enter display group Lax. input value = 255
- Select function "066" in button field - 2- For "Display group number 066" and press Q button to confirm input.


Display on VAS5051:







1 - Display group 66
2 - Display field 1
Display field 2
Display field 3
Display field 4


NOTE: If no display follows, a display field is not assigned.


NOTE: For vehicles with automatic transmission, the voltage supply For the cruise control switch is not switched on until a speed of above 30 km/h is reached with selector lever in position -2-, -3- or - D-. The voltage supply will then be maintained at idle, as long as a driving mode (aside from -1- or -R-) is selected.


- Road test vehicle and exceed 30 km at least once. Do not switch off engine upon completion. Leave selector lever in -2-, -3- or -D-.
- Engage parking brake.

For 4-digit indication in display field 2 and 4:
- Check indication in display field 2.

Test requirement Display field 2
Cruise control system switched free 1) 1 0 0 0
Brake pedal depressed 1 0 1 1
Clutch pedal depressed 1 1 0 0

1) If the value 0 is indicated: Activate cruise control system







- Check indication in display field 4.

Test requirement Display field 4
Switch B on "OFF" engaged 0 0 0 0
Switch B at "ON" 0 0 1 1
Switch A pressed, "FIX" 0 1 1 1
Switch B at "SET" 1 0 1 1
Switch B at "OFF", before the engaging point (delay) 0 0 0 1

If specified values are not obtained:
- Check wire connections.

For 8-digit indication in display field 2 and 4:
- Check indication in display field 2.

Test requirement Display field 2
Cruise control system switched free 1) 0 0 0 0 1 0 1 1
Brake pedal depressed 0 0 0 0 1 0 1 1
Clutch pedal depressed 0 0 0 0 1 1 0 0

1) If the value 0 is indicated: Activate cruise control system.







- Check indication in display field 4.

Test requirement Display field 4
Switch B on "OFF", engaged 0 0 0 0 0 0 0 0
Switch B at "ON" 0 0 0 0 0 0 1 1
Switch A pressed ," FIX" 0 0 0 0 0 1 1 1
Switch B at "SET" 0 0 0 0 1 0 1 1
Switch B at ""OFF", before the engaging point (delay) 0 0 0 0 0 0 0 1

If specified values are not obtained:
- Check wire connections.

Checking wire connections
- Disconnect harness connector at cruise control switch:
- Connect VAG1598/31 test box to disconnected harness connector of Engine Control Module (ECM),







- Check the following wire connections For open circuit and short circuit to Ground (GND) and B+:

Harness connector VAG1598/31 test box

Terminal Socket
2 75
3 57
4 38
5 76
6 equipment and model year dependent, depending on fuse or automatic transmission
7 38

- Repair open circuit or short circuit if necessary.