Before entering on-board diagnostics, see PRETEST INSPECTION . Turn ignition switch to OFF position. Locate self-diagnostic connector, which is next to fuse block. Using an analog voltmeter, connect volt-meter positive lead to self-diagnostic connector terminal No. 1 (output) and negative lead to terminal No. 12 (ground). See Fig 1 .
Turn ignition switch to ON position and disclosure of ECU 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 abnormal code(s), perform necessary repair. See FAULT CODES .

Fig 1: Self-Diagnostic Connector Terminal ID

Courtesy of CHRYSLER MOTORS.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Retrieving Codes (Using Voltmeter)