Reading Diagnostic Trouble Codes

Fig. 2 MPI Self Diagnostic Chart:

Trouble code indications are made by reading voltmeter deflections. The voltmeter is connected to the self-diagnosis connector located in the glove box and if the indication is normal, the voltmeter will indicate a reading as shown, Fig. 2. If abnormal, refer to malfunction codes 1 through 8, Fig. 2.
. When necessary to determine diagnostic code, proceed as follows:
1. Turn ignition switch Off.
2. Open glove compartment, then pull out diagnostic connector.
3. Connect a suitable voltmeter between MPI terminal and ground.
4. Turn ignition switch On and note that an immediate indication of ECU memory contents will begin. If the system is in normal condition, pointer of voltmeter deflect as previously described and in the case of an abnormal condition, the voltmeter will deflect accordingly.
5. After recording the abnormal items, check and repair each part as directed, Fig. 2.
6. Turn ignition switch Off.
7. After repairs have been completed, disconnect battery ground cable for at least 15 seconds to erase abnormal code from memory.