NOTE: Check for applicable technical service bulletins before proceeding. Do not perform the following procedure if no driveability conditions exists, unless directed here from another procedure. Do not turn ignition off during the following procedure or clear DTCs unless instructed to do so.

If vehicle does not crank, see appropriate STARTERS article in STARTING & CHARGING SYSTEMS. Ensure battery is fully charged and cables are clean and tight. Ensure Powertrain Control Module (PCM) grounds are clean, tight, and in proper location. See WIRING DIAGRAMS article. PCM is located in left front corner of engine compartment, inside air filter housing. Install scan tool. If scan tool powers up, go to next step. If scan tool does not power up, see SCAN TOOL DOES NOT POWER UP under SYSTEM TESTS.
Turn ignition on. Attempt to establish communication with PCM. If scan tool communicates with PCM, go to next step. If scan tool does not communicate with PCM, diagnose communication problem. See TEST F: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
Attempt to start engine. If engine starts and idles, go to next step. If engine does not start and idle, diagnose engine cranks, but does not start. See NO-START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
Using scan tool, select DTC display function for PCM. If any DTCs are displayed, go to next step. If no DTCs are displayed, go to step 9.
Using scan tool, select CAPTURED INFO function to store PCM DTC information. After storing PCM DTC information, go to next step.
If scan tool displays any DTCs that begin with "U", perform appropriate DTC test. See DIAGNOSTIC TROUBLE CODES in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool does not display any DTCs that begin with "U", go to next step.
If scan tool displays DTC P0601 or P0602, repair DTCs as necessary. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If scan tool does not display DTC P0601 or P0602, go to next step.
If scan tool displays DTC P0560 or P0620, see appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. If scan tool does not display DTC P0560 or P0620, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
If customer's concern is with the automatic transmission, see appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS. If customer's concern is not with the automatic transmission, go to next step.
If customer's concern is not Inspection/Maintenance (I/M) testing-related, go to next step. If customer's concern is I/M testing-related, perform INSPECTION/MAINTENANCE SYSTEM CHECK under INSPECTION/MAINTENANCE PROCEDURES.
If customer's concern is MIL inoperative, diagnose MIL circuits. See MALFUNCTION INDICATOR LIGHT INOPERATIVE under SYSTEM TESTS. If customer's concern is MIL always on, diagnose MIL circuits. See MALFUNCTION INDICATOR LIGHT ALWAYS ON under SYSTEM TESTS. If customer's concern is a driveability problem, diagnose by symptom. See appropriate TROUBLE SHOOTING - NO CODES article.

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

Powertrain Diagnostic System Check

Use the Manual With the Right Hardware

When to See a Mechanic

Rather have a pro handle this?