Self-diagnosis indicators
The Quick Index or Diagnostic Card covers the most common electronic fuel control system failures. The causes of malfunctions are listed in order of difficulty to check and correct them. Review all reported causes of failures. If this does not work, then you should refer to a more detailed description of possible problems. These faults are classified by fault codes identified by LED flashes.
In almost all cases described, the SNEKS ENGINE control light should be on (turn on and burn). This immediately indicates that the electrical part of the fuel injection control system is faulty. Therefore, you should first check what the self-diagnosis LED display located in the ECU module shows. On some models, only a very limited number of codes do not turn on the indicator light on the instrument panel. In the event that the driving performance of the car deteriorates, you should check if there are fault codes in the computer memory.
The 1985 Accord has four LEDs for displaying fault codes. These LEDs are part of the ECU module, which is located under the passenger seat on Accord models, and on the left side panel near the rear seat on Prelude models. The LEDs are numbered from right to left with numbers 1,2,4,8.
Number of blinks of the self-diagnosis indicator (left column) and the systems it points out to be faulty (right column), for Accord and Prelude 1986-89.
0 | ECU |
1 | OXYGEN A |
2 | OXYGEN CONTENT IN |
3 | ABSOLUTE. MANIFOLD PRESSURE |
5 | |
4 | CRANKSHAFT ANGLE |
6 | REFRIGERANT TEMPERATURE |
7 | DROS ANGLE. FLAPERS |
8 | TDC POSITION |
9 | CYLINDER POSITION 1 |
10 | TEMP. INTAKE AIR |
12 | EGR SYSTEM |
13 | ATMOSPHERE. PRESSURE |
14 | ELECTR. H.H. MANAGEMENT |
15 | EXIT. IGNITION SIGNAL |
16 | FUEL INJECTOR |
17 | VEHICLE SPEED SENSOR |
On 1986-89 Accord models. and Prelude models have only one LED. It indicates the fault code by the number of consecutive flashes. The ECU is located under the driver's seat on specified Accord models, and on the left side panel near the rear seat on Prelude models.
Sometimes the warning light on the instrument panel and / or the LED comes on (LEDs) on the ECU is nothing more than a bad electrical connection. To detect a bad connection, determine the fault code from the LED, and check all electrical contacts associated with the nodes indicated in the diagnostic card. Erase the contents of the ECU memory as described. Start the engine, drive the car for a few minutes and check the LED again (LEDs). If they show the same codes, then there are problems in the nodes themselves. If the LEDs do not light up, then the fault was only in bad contacts.
The memory of turning on the control light on the instrument panel is erased after the ignition is turned off. In contrast, the memory of the LED readings is not erased. The control lamp will not light up again with the ignition on, unless a malfunction is detected again. Therefore, troubleshooting must be carried out according to the indications of the LEDs, regardless of the control light.