ECU Diagnostic Codes
Diagnostic Error Code Chart For the Honda Prelude
Troubleshooting Self-diagnostic Procedure
| INDICATOR BLINKS | SYSTEM INDICATED | HELM PAGE |
| 0 | ECU | 11-31 |
| 1 | OXYGEN SENSOR | 11-36 |
| 3 | MANIFOLD PRESSURE (MAP) | 11-44 |
| 5 | MANIFOLD PRESSURE (MAP) | 11-48 |
| 4 | CRANK ANGLE (CRANK SENSOR) | 11-50 |
| 6 | COOLANT TEMPERATURE (TW SENSOR) | 11-52 |
| 7 | THROTTLE ANGLE | 11-54 |
| 8 | TDC POSITION (TDC SENSOR) | 11-50 |
| 9 | No. 1 CYLINDER POSITION (CYL SENSOR) | 11-50 |
| 10 | INTAKE AIR TEMPERATURE (TA SENSOR) | 11-56 |
| 12 | EXHAUST GAS RECIRCULATION SYSTEM (EGR) | 11-135 |
| 13 | ATMOSPHERIC PRESSURE (PA SENSOR) | 11-58 |
| 14 | ELECTRONIC AIR CONTROL (EACV) | 11-76 |
| 15 | IGNITION OUTPUT SIGNAL | 11-60 |
| 16 | FUEL INJECTOR | 11-96 |
| 17 | VEHICLE SPEED SENSOR | 11-62 |
| 20 | ELECTRIC LOAD DETECTOR (ELD) | 11-64 |
| 23 | KNOCK SENSOR | 11-68 |
| 30 | A/T Fl SIGNAL A | 11-70 |
| 31 | A/T Fl SIGNAL B | 11-70 |
| 41 | OXYGEN SENSOR HEATER | 11-38 |
| 43 | FUEL SUPPLY SYSTEM | 11-42 |
If codes other than those listed above are indicated, verify the code. If the code indicated is not listed above, replace the ECU.
The Check Engine light may come on, indicating a system problem when, in fact, there is a poor or intermittent electrical connection. First, check the electrical connections, clean or repair connections if necessary.
The Check Engine light and D4 light may light simultaneously when the self-diagnosis indicator blinks 6, 7and 17.
Check the PGM-FI system according to the PGM-FI control system troubleshooting, then recheck the D4 light. If it lights, see page 14-36, 37.
The Check Engine light does not come on when there is a malfunction in the A/T Fl signal or Electric Load Detector circuits. However, it will indicate the codes when the Service Check Connector is jumped.
These codes and page references pertain to the Helm Service Manual. You can obtain a helm manual from our Downloads