Appendix:Code Output Format
198924-01-92 Fuel System Diagnosis 24-01-92
APPENDIX: Code Output Format
SERVICE CODES
The engine control system communicates service information to the technician through the Self-Test service codes. These service codes are two-digit numbers representing the results of Self-Test.
The service codes are transmitted on the self-test output (STO) line found in the vehicle SelfTest connector. They are in the form of timed pulses, and read by the technician on a voltmeter or on the STAR tester.
1. Code cycle break
The time between service code cycles is 4.0 seconds (the time the light is off).
2. First digit of service code (tens position)
The digit in the tens position of the service code represents the number of times the buzzer is on 1.2 second during one cycle.
3. Second digit of service code (ones position)
The digit in the ones position of the service code represents the number of times the buzzer is on 0.4 second during one cycle.