Without Scan Tool

NOTE: Read entire procedure before beginning. View images as corresponding text is read to ensure all steps and results are clearly understood. Display of Diagnostic Trouble Codes (DTC) AND completion of the Diagnostic Test Mode (DTM) MUST be done before it is possible to erase stored codes. Follow all steps exactly and complete entire procedure.

ON-BOARD DIAGNOSTICS -- ACCESS INFORMATION
A Volkswagen VAG 1551 scanner is recommended to access the On Board Diagnostics (OBD) and display Diagnostic Trouble Codes.

This is an alternate procedure to access the OBD and display Diagnostic Trouble Codes. This alternate method uses the Malfunction Indicator Lamp (MIL) to display the Diagnostic Trouble Codes. Trouble codes are displayed as light flash pulses from the MIL (flash pulses are also known as "blink codes" or "flash codes"). Initiation of trouble code output involves connecting an OBD1 Adaptor, OR Self-made Jumper Wire (both described below) to the 16 Pin Diagnostic Link Connector (DLC). Once properly connected to the DLC, a timed connect-disconnect procedure with the adaptor or jumper wire will start the DTC display. Erasing trouble codes and initiation of the Diagnostic Test Mode can be done using the OBD1 adaptor or jumper wire assembly as well.

By correctly and completely following all steps of this procedure, a qualified technician can successfully access the Motronic system's On-Board Diagnostics. The data collected will be as accurate and reliable as data received through a scanner.

OBD 1 Adaptor:

OBD1 Adaptor Location under rear seat bench:

OBD1 ADAPTOR
Diagnostic Trouble Code display can be achieved using the OBD1 ADAPTOR provided with the vehicle (see image). Most cars were shipped with one under the rear seat (see image), if not, an adaptor MAY be obtained from the dealer. If OBD1 adaptor is not available, use self-made jumper wire assembly described below.

Self-made Jumper Wire With Soldered Ends:

SELF-MADE JUMPER WIRE ASSEMBLY
Trouble Code display can also be achieved using a SELF-MADE JUMPER WIRE ASSEMBLY (see image) which can be constructed from readily available electrical connectors.

The jumper wire shown here, and the OBD1 adaptor described above, are used in the same manner throughout this procedure and will give identical results.

TROUBLE CODE DISPLAY REQUIREMENTS AND SETUP
1. Battery voltage must be GOOD (at least 11.5 volts).
2. Fuse # 22 in fuse/relay panel must be GOOD.
3. Ground connections on engine and transmission must be GOOD (grounds located below lower part of intake manifold).

DLC Location Passat:

4. Remove access panel for Data Link Connector by carefully prying trim panel off below instrument cluster to the right of the steering.

16-Pin Data Link Connector Pin Source I.D. And Location:

5. Check voltage at 16-Pin data link connector and note polarity of terminals. Polarity MUST be as shown. If not, repair as needed before proceding.
6. The Malfunction Indicator Lamp, located in the instrument panel, MUST light up when the ignition is switched ON and go OFF when the engine is shut OFF. If a DTC is stored in memory, the MIL lights even with the engine RUNNING, but will shut OFF when engine is shut OFF.

OBD 1 Adaptor:

7. If using OBD1 ADAPTOR, check fit of OBD1 adaptor onto DLC connector then remove.

- DO NOT LEAVE ADAPTOR CONNECTED TO DLC AT THIS TIME.
- If self-made jumper wire is being used, proceed to step 8.

Jumper Wire To 16-Pin DLC Hookup, Jetta Shown:

8. If using JUMPER WIRE, insert jumper wire connector "W1" into DLC terminal #4 and jumper wire connector "W2" into DLC terminal #15 as shown.

- DO NOT JOIN CONNECTORS "J1" AND "J2" AT THIS TIME.

9. The DTC display procedure should be completed with ENGINE RUNNING if possible.

- If engine does not RUN or will not START, crank engine for 5 to 6 seconds. Leave ignition switch ON after cranking.

CAUTION: To avoid overheating starter motor, DO NOT crank engine for longer than 15 seconds.

NOTE:
- Ignition switch MUST BE LEFT ON after cranking for the entire procedure. Failure to do so makes test invalid.

- Code 2111 (Engine Speed Sensor) and/or code 2113 (Camshaft Position Sensor) should always be displayed when ignition switch is ON and engine is NOT RUNNING. This fault display is normal and can be ignored when displaying trouble codes with engine NOT RUNNING.

- However, if the Engine Speed Sensor or Camshaft Position Sensor are suspected of causing the NO START CONDITION, they should be tested separately. Use the test procedures at the individual component level.

TROUBLE CODE DISPLAY PROCEDURES
1. START engine and let idle (1300 rpm maximum), or crank engine if no start condition exists.
2. Connect OBD1 adaptor to 16-Pin DLC, or if jumper wire is being used, join together jumper connectors J1 and J2.

- MIL in dash MUST light up.
- IF NOT:

- Check wires from DLC to the Motronic ECM for open.
- Check adaptor/jumper connections.

16-Pin Data Link Connector And Jumper Wire, Jetta Shown:

3. After approx. 4 seconds, remove OBD1 adaptor or separate jumper connectors J1 and J2 (reverse of step 2).

- MIL will go OFF, come ON for 2.5 seconds, then go OFF.
- This confirms display signal has been received.
- MIL will then display (flash) trouble code pulse groups.
- Converting pulse groups to trouble codes found in Step 5.

4. Count MIL flashes and record flash pulse groups as they display from the MIL.
5. Repeat display activation steps 2 and 3 to display next code as only one code will be displayed for each activation.

Reading Fault Codes:

6. Each blink code is comprised of 4 flash pulse groups with a maximum of 4 flashes per group. Compile the number of flashes in each of the 4 pulse groups to determine the 4 digit code being displayed.
7. If NO codes are present, code 4444 will display and no further action is necessary.
8. If codes OTHER THAN 4444 are present, repeat display activation steps 2 and 3 until all codes are displayed.
9. Once all trouble codes have been displayed, code 0000 (end of trouble code output) will display.

- Code 0000 display --- 2.5 second flash (meaning number zero) at 2.5 second intervals.

10. Refer to DIAGNOSTIC CHARTS for explanation of trouble codes. Testing and Inspection
11. Refer to HOW TO CLEAR DIAGNOSTIC TROUBLE CODES. [1][2]Clearing Diagnostic Trouble Codes