1. Prepare your vehicle:
- Turn on the ignition and let the engine run for a few minutes.
- Turn off the engine.
2. Jumper the ALDL connector:
- Locate the ALDL (Assembly Line Diagnostic Link) connector under the dashboard, usually near the steering column.
- Connect a jumper wire between the "A" and "G" terminals of the ALDL connector.
3. Turn on the ignition:
- Turn on the ignition, but don't start the engine.
- The check engine light should start flashing.
4. Count the flashes:
- The check engine light will flash a series of codes. Each code consists of two sets of flashes.
- The first set of flashes indicates the tens digit of the code, and the second set indicates the units digit.
- For example, if the light flashes four times, pauses, and then flashes once, the code is 41.
- Write down each code as you see it.
5. Interpret the codes:
Consult a DTC lookup table for your specific vehicle to determine the meaning of each code.
6. Clear the codes:
After you have recorded all the codes, you can clear them by disconnecting the battery for a few minutes or by disconnecting the ALDL jumper wire.
Note: If the check engine light doesn't flash any codes, it means that there are no stored codes in the ECU.
