Data Link Connector Wiring Checking
DIAGNOSING DATA LINK CONNECTION FAULTSIf VAG Scan Tool has no display:
- Check VAG 1551/3 harness for continuity.
- Check Data Link Connector (DLC) wire connections.
If VAG Scan Tool displays:
"Control module does not answer"
- Check VAG 1551/3 harness for continuity.
- Check DLC wire distributors "K" and "L" and DLC.
If VAG Scan Tool displays one of the following:
"L" wire not switching to Ground"
"L" wire not switching to B+"
"K" wire not switching to Ground"
"K" wire not switching to B+"
- Check Data Link Connector (DLC) wire connections.
If VAG Scan Tool displays:
"Error in Communication Link"
- Check DLC wire distributors "K" and "L" and DLC.
TESTING PROCEDURES
Checking VAG 1551/3 harness for continuity
- Use an ohm meter to check for continuity of the harness terminals according to the image and chart.
CONNECTOR A CONNECTOR B
4 3 - Ground
16 2 - Battery positive voltage (B+)
15 4 - L wire
7 1 - K wire
14 5 - Malfunction Indicator Lamp (MIL) wire
Checking Data Link Connector (DLC) wire connections.
The DLC wiring distributors K and L for all vehicle systems with On Board Diagnostics are located in the relay panel located in the left side of the plenum tray.
The 16-pin DLC is located in the rear of center console or in lower left corner of instrument panel, to left of steering wheel.
- Test the DLC wiring using the Fluke 83 multimeter, VW 1594 adaptor kit or equivalent test equipment.
Notes:
- Check wiring for open circuits or short circuits to positive (B+) and Ground (GND) using digital multimeter Fluke 83 or equivalent.
- Switch ignition off before checking wiring.
Auxiliary Relay Panel 1:
DLC CONNECTOR: CONNECTED TO:
4 3 - Ground
16 2 - Battery positive voltage (B+)
15 4 - L wire distributor (in relay panel)
7 1 - K wire distributor (in relay panel)
- Repair wires according to wiring diagram as needed.
Checking DLC wire distributors "K" and "L" and DLC
Note: Other vehicle systems having "Rapid data transfer" On Board Diagnostic (OBD) (for example automatic transmission) are also connected to DLC wiring distributor terminal "K". For other systems with OBD, see wiring diagrams.
- One at a time, disconnect all other wiring connections for vehicle systems having OBD from DLC wiring distributors "K" and "L".
- After each wiring connection to a vehicle system is disconnected, let engine idle and insert the appropriate address word for the system to be tested.
If the control module identification code is now displayed, then the last system (control module) disconnected is causing the problem:
- Check wiring to that system (control module) for open/short circuits according to wiring diagram.
If a malfunction is not found in the wiring, reconnect the last system (control module) and all connectors to OBD wiring distributors "K" and "L".
Note: If "Control module does not answer" is displayed, the wiring connection to that control module was interrupted.