Clearing Diagnostic Trouble Codes (Resetting the Control Module)

In the event of a PGM-FI system electrical malfunction, a dash mounted indicator lamp will light and stay lit. If the dash warning lamp is on, or if a system malfunction is suspected even though the lamp is off, it is necessary to check the electronic control unit LED display. The LED display is on the ECU, and the indicator lamps operate whenever the ignition is on and a trouble code is stored in the ECU memory.
A single LED is used. When an abnormality is detected the LED display on the ECU blinks. The LED blinks a certain number of times, with the number of blinks indicating the number of the failure code. After the LED blinks a number of times there will be a 2 second pause and the LED will blink out the number of the next failure code.
System diagnosis requires the use of a suitable digital multimeter and system checker harness 07999-PD6000A. The harness checker allows test connections to be made at the ECU, while leaving the main harness connectors connected.
To diagnose system malfunctions, start with the TROUBLE CODE DIAGNOSIS / DIAGNOSTIC CHARTS-START DIAGNOSIS HERE section. If a problem can not be resolved using the preliminary self-diagnosis chart, proceed to PGM-FI SELF-DIAGNOSIS CHARTS section. Read through charts noting bold faced type and locate chart that corresponds to the trouble code, most closely describes the symptom and/or operation of warning LED. Follow tests exactly and repair any malfunctions found before proceeding to next step. After completing diagnosis and repairs, clear self-diagnosis codes from memory by disconnecting the battery ground cable for at least 10 seconds. After connecting the cable, check to see that the LED display is turned off.