Service Code Output Format

Fig. 22 Service code format:

Fig. 23 Time pulse format. Except V6-171 engine:

Fig. 24 Time pulse format. V6-171 engine:

The EEC-IV 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 (found in the self-test electrical connector) in the form of time pulses, and read by the use of a voltmeter or a STAR tester.
The pulse format is (refer to Figs. 22, 23 and 24) as follows:
1. One-half second on-time for each digit.
2. Two seconds off-time between digits.
3. Four seconds off-time between codes.
4. Six to nine seconds off-time before and after the half-second separator pulse.