Diagnostic Trouble Code (DTC) Output Format Description

Fig. 15 Reading service code cycle break:

Fig. 16 Reading first digit of service code:

Fig. 17 Reading second digit of service code:

The EEC and 4EAT system transmits its information by the use of the self-test service codes. These service codes are two digit numbers representing the results of the self-test. The service codes are transmitted on the self-test output line found in the vehicle self-test connector. They are in the form of timed pulses, and read by the use of a voltmeter or a Super Star Tester ll. 1. Code cycle break. The time between service code cycles is 4.0 seconds, Fig. 15.
2. First digit of service code (tens position) during one cycle, Fig. 16.
3. Second digit of service code (ones position) during one cycle, Fig. 17.