Reading and Clearing Diagnostic Trouble Codes

Prior to starting the fault display, check the ground connections between the engine compartment and the intake manifold. Also check the ignition coil power stage and related components for faulty wiring, corrosion, or faulty terminals.
The fault codes are only maintained as long as the engine is running. If the ignition is shut off, the fault memory is lost and the car must be driven for at least 5 minutes for the control unit to sense the faults and store them in memory again.
The fault displays for both control units are displayed sequentially;
1. First the fault memory content of the ignition control unit is displayed until fault display 0000 is shown.
2. Then the fault memory of the fuel injection control unit is displayed until fault display 0000 is shown.

Fig. 27 Fuse Inserted In Fuel Pump Relay:

To start the warning lamp in the instrument panel displaying the fault codes, bridge the terminals on top of the fuel pump relay, Fig. 27, with a spare fuse for at least 4 seconds with the engine running at less than 2000 rpm. The engine warning light in the instrument cluster should begin flashing as soon as the fuse is removed from the fuel pump relay.
The first code to be displayed will be for the ignition system. If code 4444 is displayed, no faults are present. Re-insert the fuse in the fuel pump relay, and code 0000 should flash, indicating the end of the ignition fault sequence. Insert the fuse in the fuel pump relay again to begin the fuel system fault display. Keep inserting the fuse into the fuel pump relay until code 0000 is displayed, signaling the end of the fuel system fault sequence.
Note: If no faults are recorded in either memory, the fault display sequence may read; 4444, 4444, 0000, without a 0000 after the ignition code.
If the fault lamp does not light up with the ignition on and after initiating the fault display, but does light up when the terminals on the fuel pump relay are bridged, check the wiring from the control unit to the fault lamp. If the wiring is not faulty, either the fuel injection, or ignition control unit could be defective.