Using Voltmeter
- Before entering on-board diagnostics, see SERVICE PRECAUTIONS . Turn ignition switch to OFF position. Locate both Data Link Connectors (DLC), next to fuse block. Connect voltmeter positive lead to diagnostic output terminal and negative lead to either DLC ground terminal. See Fig 2 .
- Turn ignition switch to ON position. Disclosure of ECM memory will begin. If 2 or more systems are non-functional, they are indicated by order of increasing code number. Indication is made by 12-volt pulses of voltmeter pointer. A constant repetition of short 12-volt pulses indicates system is normal. If system is abnormal, voltmeter will pulse between zero and 12 volts.
- Signals will appear on voltmeter as long and short 12-volt pulses. Long pulses represent tens; short pulses represent ones. For example, 4 long pulses and 3 short pulses indicate Code 43. After recording trouble code(s), perform necessary repair(s) to indicated circuit(s). See TROUBLE CODES .