Without Scan Tool

Fig. 107 Fault Code Chart (PGM-FI Engine):

When the CHECK ENGINE warning light has been reported on, turn the ignition on, move the driver's seat to the front position and observe the LED on the rear of the Electronic Control Unit (ECU). The LED indicates a system failure by it's blinking frequency.

If the ECU indicates codes 4, 11, 15, 16, or exceeds 17, count the blinks again. If the indicator is blinking these codes, substitute a known-good ECU and recheck. If the indication goes away, replace the original ECU.

The CHECK ENGINE warning light and ECU LED may come on, indicating a system failure, when in fact, there is a poor or intermittent connection. First, check the electrical connections, clean or repair connections if necessary.