When the "Check Engine'' warning light on the dashboard comes on and stays on, it indicates a problem in the fuel injection/emissions system. Check the ECU for fault codes. On certain models, some codes will not trigger the check engine light; if driveability has suffered, check for stored fault codes.
The most common error when using fault codes is to assume the indicated component has failed rather than checking the entire circuit. The presence of a trouble code means simply that the electrical circuit for the named component is not functioning properly. For example, a code for the oxygen sensor circuit does not automatically mean the oxygen sensor has failed. A wire terminal may simply be loose or corroded at the connector. When using diagnostic or fault codes, always remember that the entire circuit including the component must be checked carefully.
On 1990-95 Accord (except V-6) and 1992-95 Prelude, the codes are read from the check engine light after the two-wire service connector has been jumpered. On Accords, the service connector is under the dash on the passenger side. On Preludes, it is located behind the center console. Codes 1 through 9 are indicated by a series of short flashes; two-digit codes use a long flash for the first digit followed by the appropriate number of short flashes. For example, Code 14 would be indicated by 1 long flash followed by 4 short flashes. Codes are separated by a pause between displays. Multiple codes are transmitted in an alternating pattern. For example, a code 3 and 14 would be displayed as 3 short flashes (for Code 3) followed by the separator pause, then 1 long flash and 4 short flashes (for Code 14).
Fig. 7: Fault codes are read from the check engine light on most late-model vehicles
Fig. 8: On Accords, the service connector is located under the dash on the passenger side
Fig. 9: The service connector on Preludes is located behind the center console
- Use a jumper wire to connect the two terminals of the service connector together.
- Turn the ignition switch ON; the check engine light will display any stored codes by rhythmic flashing.
NOTE: In the event that a code is encountered which is not on the chart, re-count the number of flashes. If the code is truly wrong, it will be necessary to swap the ECU for a known-good unit and recheck. Since this can be expensive, you may wish to bring the car to a reputable repair facility if no other cause of the failure can be found. This may save you the expense of purchasing an unnecessary part.
- If no codes are displayed but a driveablity problem exits, testing of the system individual components is necessary to find the problem. If codes are displayed, follow the appropriate troubleshooting chart in this section.
Fig. 10: Fault code chart for 1990-93 Accords
Fig. 11: Fault code chart for 1994-95 Accords (four cylinder)
Fig. 12: Fault code chart for 1992-95 Preludes