Retrieving Codes
Service codes are retrieved from the EEC system through the Self-Test connector by using a Scan tool, analog volt/ohmmeter or the CHECK ENGINE light. The KOEO and KOER SELF-TESTS are used for this purpose. After these codes have been recorded or repaired, they may be cleared from the ECA memory.
All service codes are 2 digit numbers, which are generated one digit at a time. These codes indicate a current fault in the system. They must be serviced in the order in which they appear. Use the appropriate service code chart to find the correct CIRCUIT TEST.
If a Scan tool diagnostic tester is used, it will count the pulses and display them as a digital code. The SUPER STAR II tester will add a zero (0) to single digit codes. See Fig 1 .
If an analog voltmeter or the CHECK ENGINE light is being used, pay careful attention to the length of the pauses between signals in order to read the codes correctly. The first digit in a service code will be indicated by 1.2 second signals separated by a 0.4 second pause. There is a 1.6 second pause between the first digit and second digit. The second digit is indicated by 0.4 second signals separated by 0.4 second pauses. There will be a 4 second pause between each service code.