The Self Diagnostic System Check is an organized approach for identifying a problem caused by the on-board computer controlled electronics. Understanding this chart and using it correctly will reduce diagnosis time and prevent the unnecessary replacement of parts. If you have not reviewed the basic information on how to use the computer Self-Diagnostics, go to the beginning of this section.

NOTE: The following step numbers refer to circled numbers on diagnostic chart. See Fig 1.

The first step checks to see if it is possible to enter diagnostics. If diagnostics can be entered and there is a trouble code displayed, a problem has been detected by the system that can be corrected by following the appropriately numbered code chart.
If diagnostics can't be entered or there are no trouble codes present, note the condition of the Driver Information Center.
If the DIC displays a "SYSTEM FAULT" message, the problem is most likely in the dataline.
If the DIC is blank and the IPC display is not normal, the problem is in either the wake-up circuit or Ignition 3 to THE BCM.
If the DIC is normal and the IPC is normal, check the ISC motor. If it does not retract and extend, refer to CHART 6C-6: IDLE SPEED CONTROL (ISC) CHECK .

NOTE: Self-diagnositic system check charts A through C are located under SELF-DIAGNOSTICS SYSTEM CHECK CHARTS .

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

Self-Diagnostics System Check

Use the Manual With the Right Hardware

When to See a Mechanic