Without Scan Tool

The ECU is capable of self diagnosis. When a system malfunction is detected, the ECU will illuminate the ``Check Engine'' lamp and store a related trouble code in ECU memory. Trouble codes may be read using code tester tool No. 9268 or system tester tool No. 9288 or equivalents, or through flashing of the ``Check Engine'' lamp. To display the stored trouble codes through the ``Check Engine'' lamp, proceed as follows:

1. With engine off, turn ignition switch to ON position.
2. Depress accelerator pedal completely for 3-5 seconds.

Fig. 1 Trouble code flash sequence:

3. Wait for ``Check Engine'' lamp to flash, then release accelerator pedal. ECU will begin to flash trouble codes. Image is an example of the flash sequence for trouble code 1124 (oxygen sensor).
4. Fully depress accelerator pedal to display next trouble code. When trouble code 1000 is displayed, no additional codes are stored are memory.

NOTE: ECU memory will be erased if the ECU connector is removed or the battery is disconnected.