Tools - Diagnostic Trouble Codes Displaying Adapter

Group: 01

Number: 94-01

Date: Oct. 15, 1994

Subject:
Diagnostic Trouble Code (DTC) Memory blink codes, displaying

Model(s):
Golf III / Jetta III / Cabrio
2.0 liter (engine code ABA) from 1995 m.y.

The following Repair Manual pages are new and will be integrated into the next Repair Manual update.

Diagnostic Trouble Code (DTC)

Memory, displaying blink codes

Starting with 8.94 production (1995 m.y.), Golf III, Jetta III and Cabrio vehicles are equipped with a special OBD1 adapter for use with the On Board Diagnostic (OBD) system.

OBD1 Adapter:

The adapter is used to check Diagnostic Trouble Code (DTC) Memory when the VAG 1551 Scan Tool (ST) is not available. Stored malfunctions are displayed as blink codes by the Malfunction Indicator Lamp (MIL) in the vehicle.

OBD1 Data Link Connector:

Blink code display is activated by using the adapter in conjunction with the vehicle's Data Link Connector (DLC). The adapter makes connection between connector sockets 15 (L-wire) and 4 (Battery Ground).

Malfunction recognition

If the Engine Control Module (ECM) detects a malfunction, the information will be stored in permanent memory and the Malfunction Indicator Lamp (MIL) will be illuminated.

Note:
The MIL is illuminated when the ignition is switched on (check function). It stays on, going out once the engine has been started.

Each stored malfunction is represented by a four-digit numerical blink code. When the display is activated, the Malfunction Indicator Lamp (MIL) will illuminate and blink the four-digit code. Blink codes are listed along with Diagnostic Trouble Codes (DTC) in the DTC tables.

Blink code sequence

The display sequence begins with the MIL blinking once. Approx. one second later the blink code sequence will begin.

The MIL will blink 1 to 9 times to display the first digit, then pause, blink again 1 to 9 times to display the second digit, and so on until all four digits have been displayed.

Displaying DTC blink codes

- Switch ignition ON.

- Connect OBD1 adapter to Data Link Connector (DLC) for 2.5 seconds, then
disconnect.

^ First blink code will be displayed

Note:
The code 4 - 4 - 4 - 4 indicates no malfunctions stored.

- Connect OBD1 adapter again for 2.5 seconds, then disconnect.

^ Next blink code will be displayed

- Repeat procedure, connecting and disconnecting adapter and reading additional blink codes, until no more codes are displayed (0 - 0 - 0 - 0).

- Switch ignition OFF.

Erasing DTC Memory

- Connect OBD1 adapter to DLC.

- Switch ignition ON

- Leave adapter connected for at least 5 seconds, then disconnect.

- Connect OBD1 adapter for 2.5 seconds, then disconnect.

^ Blink codes displayed

- Repeat until no more codes displayed (0 - 0 - 0 - 0).

- Connect OBD1 adapter again for 2.5 seconds.

^ DTC codes will be erased from DTC Memory

- Switch ignition OFF.

Adapter location-under rear seat bench

OBD1 Adapter Location:

Vehicles without anti-lock brakes (ABS)

^ Secured by strap

OBD1 Adapter Location:

Vehicles with anti-lock brakes (ABS)

^ Under ABS coaxial cable near ABS Control Module