LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Chevrolet >> 2003 >> Corvette Base, 2D Convertible, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics >> Self-Diagnostic System >> Diagnostic System Check - Engine Controls >> Diagnostic Procedures
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedures

NOTE:
  • Do not perform this diagnostic if there is not a driveability concern, unless another procedure directs you to this diagnostic
  • Before you proceed with diagnosis, search for applicable service bulletins
  • Unless a diagnostic procedure instructs you, do NOT clear the DTCs.
  • If there is a condition with the starting system, see appropriate STARTERS article in STARTING & CHARGING SYSTEMS.
  • Ensure the battery has a full charge.
  • Ensure the battery cables are clean and tight.
  • Ensure the PCM grounds are clean, tight, and in the correct location.
  1. Install a scan tool. Does the scan tool turn ON? If yes, go to next step. If no, see SCAN TOOL DOES NOT POWER UP in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
  2. Turn ignition ON, with engine OFF. Attempt to establish communication with the listed control modules. If you are using a Tech 2, obtain the information using the Class 2 Message Monitor feature:
    • PCM.
    • BCM
    • Instrument Panel (IP) cluster.
    • Anti-lock Brake System/Traction Control System (ABS/TCS).
    • Heating, Ventilation, and Air Conditioning (HVAC).

    Does the scan tool communicate with all the listed control modules? If yes, go to next step. If no, see SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.

  3. Attempt to start the engine. Does the engine start and idle? If yes, go to next step. If no, see ENGINE CRANKS BUT DOES NOT RUN under NO-START DIAGNOSIS in BASIC DIAGNOSTIC PROCEDURES - 5.7L CORVETTE article.
  4. Select the DTC display function for the following control modules:
    • PCM
    • BCM
    • IP Cluster
    • ABS/TCS
    • HVAC

    Does the scan tool display any DTCs? If yes, go to next step. If no, go to step  9.

  5. With a scan tool, select Captured Info in order to store the powertrain DTC information. When complete, go to next step.
  6. Does the scan tool display DTCs which begin with a "U"? If yes, see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If no, go to next step.
  7. Does the scan tool display DTC P0601-P0607, P1600, P1621, P1627, or P1683? If yes, see DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681 & P1683: PCM MEMORY  under DIAGNOSTIC TESTS. If no, go to next step.
  8. Does the scan tool display DTC P0562, P0563, P1637 or P1638? If yes, see appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. If no, see DIAGNOSTIC TROUBLE CODE DEFINITIONS .
  9. Is the customer's concern with the automatic transmission? If yes, see appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS. If no, go to next step.
  10. Is the customer's concern with Inspection and Maintenance (I/M) testing? If yes, see INSPECTION/MAINTENANCE SYSTEM CHECK  under DRIVE CYCLES. If no, go to next step.
  11. Review the following symptoms. See TROUBLE SHOOTING - NO CODES - 5.7L CORVETTE article.
    • Hard start.
    • Surges and/or chuggles.
    • Lack of power, sluggishness or sponginess.
    • Detonation and/or spark knock.
    • Hesitation, sag or stumble.
    • Cuts out or misses.
    • Poor fuel economy.
    • Poor fuel fill quality.
    • Rough, unstable, or incorrect idle and stalling.
    • Dieseling.
    • Run-on and backfire.

    Did you find and correct the condition? If yes, system is okay. If no, see INTERMITTENT CONDITIONS .

scientia non olet · About LEMON Manuals