On Board Diagnostic (OBD), Performing

Scan tool, connecting
All functions which could previously be performed with V A G 1551/1552 can also be performed with the new tester VAS 5051 in the operating mode vehicle OBD.
Refer to Operating instructions for Vehicle Diagnosis, Testing and Information System VAS 5051.

Note:
^ The ABS function is switched off in the control module during the On Board Diagnostic (OBD).
^ The Diagnostic Trouble Code (DTC) memory must be erased after a successfully checking and repair.

Special tools and equipment





^ VAS 5051 Vehicle Diagnosis, Testing and Information System
^ Diagnosis cable VAS 5051/1 or VAS 5051/3

Test prerequisites for OBD
^ The tires installed to all wheels must be of the same (approved) size; tires inflated to prescribed pressure.
^ Mechanical/hydraulic parts of the brake system including brake light switch and brake lights OK.
^ Hydraulic connections and lines are not leaking (visual check of hydraulic module, brake calipers, wheel cylinders, tandem brake master cylinder).
^ Wheel bearings and wheel bearing play are OK.
^ ABS Control Module (w/EDL) -J104- is correctly bolted to hydraulic unit -N55-.
^ Electrical connection is installed correctly to the ABS Control Module (w/EDL) -J104- (locking device is engaged correctly).
^ Check electrical connections of ABS components for damage and correct seating.
^ All fuses, according to wiring diagram OK. (remove fuse from holder to check).
^ Supply voltage OK. (at least 10.0 V)
^ Access to the OBD is only possible when the vehicle is stationary and ignition turned on (or engine running).
^ When checking the ABS system make sure that the vehicle electric system is not affected by electro-magnetic interference, i.e. the vehicle is kept well away from equipment with a high current draw, e.g. from an electric welding module.

Safety precautions

WARNING:
^ You must always secure testing and measuring equipment on the rear seat.
^ When vehicle is being driven, only a second technician operate this equipment.

Scan tool connecting
All functions which could previously be performed with V.A.G 1551/1552 can also be performed with the new tester VAS 5051 in the operating mode vehicle OBD.
Refer to Operating instructions for Vehicle Diagnosis Testing and Information System VAS 5051.





Connecting VAS 5051
- With ignition switched off, connect tester VAS 5051 to Data Link
Connector using diagnosis cable VAS 5051/1 or VAS 5051/3.

Selecting operating mode:
- Press button on display for "Vehicle OBD".

Selecting vehicle system:
- Press "03. Brake electronics" on display.
The control module identification and coding are indicated on the display.

Selecting diagnosis function:
All diagnostic functions available are indicated on the display.
- Press button on display for desired function.
- Further measures see repair procedures.

Note: The following test sequences are for V.A.G 1551 scan tool.
Refer to V.A.G. 1551 Scan Tool, Connecting and Selecting Function.