Testing Procedure

To ensure correct diagnosis and repair, testing should be done in the following order:

1. If possible question customer about conditions present when malfunction occurred. Connect CONSULT-II or equivalent scan tool to Data Link Connector (DLC). DLC is located under left side of dash panel. Using scan tool, retrieve and record DTCs and freeze-frame data. See RETRIEVING DIAGNOSTIC TROUBLE CODES . If MIL is on, and DTCs are not accessible, check for ECM fail-safe mode. See FAIL-SAFE MODES . If symptoms exist, but DTCs or freeze-frame data do not exist, go to next step. If symptoms do not exist, but DTCs or freeze-frame data exist, go to step  5.
2. Attempt to duplicate conditions present when malfunction occurred. If malfunction is detected, perform basic inspection. See BASIC INSPECTION under THROTTLE POSITION SWITCH, IGNITION TIMING & IDLE SPEED in ON-VEHICLE ADJUSTMENTS article. If using CONSULT-II, go to next step. If using generic scan tool, go to step  4.
3. Check inputs and outputs in DATA MONITOR mode with CONSULT-II. See DATA MONITOR MODE  under CONSULT-II under SCAN TOOL USAGE. Compare readings with specifications listed in PIN VOLTAGE CHARTS article. If problem is found, repair as necessary. If no problem is found, go to next step.
4. Diagnose problem by symptom, see TROUBLE SHOOTING - NO CODES article. If malfunction cannot be verified, problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
5. Clear DTCs and freeze-frame data. See CLEARING DIAGNOSTIC TROUBLE CODES . Attempt to reset DTC by performing DTC CONFIRMATION TEST in appropriate diagnostic test. If multiple DTCs are present, diagnose in order of priority. See MULTIPLE DTC PRIORITY IDENTIFICATION  table. If DTC does not reset, problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. If DTC resets, go to next step.
6. Perform appropriate diagnostic procedure under DIAGNOSTIC TESTS. After repairs are made, perform appropriate DTC CONFIRMATION TEST to verify repair. Clear DTCs. If SRT codes are not set, drive vehicle in specified driving pattern to set all SRT codes. See DRIVE CYCLES .