Refer to Engine Error Codes for details on the actual codes.
The ECU diagnostics port is in the engine bay, covered by a flap marked "Diagnostics"!
The Check Engine light will flash with 1.5 seconds between digits (for multi-digit codes), 2.5 seconds between each error code, and a 4.5 second gap before repeating. "No codes" is a flash every 0.5 second.
Thus the sequence below would translate to an Ignition problem and a problem with the Oxygen Sensor.
3 flashes -- 2.5 second gap -- 5 flashes -- 4.5 second gap -- 3 flashes -- 2.5 second gap -- 5 flashes ...
- Open the service connector (a little black box, about 1" square, at the very back of the can near air intake).
- Short the terminals marked T and E1 with a wire (a paperclip works well).
- Turn all accesories off, especially A/C.
- Put the transmission in neutral.
- Put the ignition key in ON position. The orange "Check Engine" light on the dash should flash.
Clearing the Codes
Note: The error lights will continue to show an error unless you clear the code.
Once you've identified and fixed the problem you need to clear the ECU memory, otherwise when you next get a problem, you'll see the old problem, followed by the new code. First remove the terminal short from the diagnosis box.
- Remove the 7.5A AM2 fuse in the main fusebox near the battery.
- Disconnect the battery for around 10 seconds. Obviously this is going to reset your clock, radio settings, etc.