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 - Basic Diagnostic Procedures >> Ignition Systems >> Electronic Ignition System Diagnosis >> Test Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test Description

The number below refers to the step number on the diagnostic table.

  1. 4

    Monitoring the misfire current counters determines if a fault is present.
  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 5.7L CORVETTE article.
  2. Crank engine. Observe engine speed parameter with a scan tool. Does scan tool display engine RPM? If yes, go to next step. If no, go to step  13 .
  3. Is DTC P0335, P0336, or P0351-P0358 also set? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 5.7L CORVETTE article. If no, go to next step.
  4. Idle the engine. Observe misfire current counters on scan tool. Does scan tool display any misfire current counters incrementing? If yes, go to next step. If no, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 5.7L CORVETTE article.
  5. Turn ignition OFF. Remove fuel pump relay. Test for spark at each affected cylinder with Spark Tester (J-26792). Do you have bright Blue spark on the cylinders? If yes, go to next step. If no, go to step  7 .
  6. Remove spark plugs. Inspect spark plugs for any abnormal conditions or damage. Are spark plugs in good condition? If yes, system is okay. If no, go to Step  22 .
  7. Measure spark plug wire resistance. Is resistance more than 700 ohms per ft? If yes, go to step  23 . If no, go to next step.
  8. Turn ignition OFF. Disconnect affected ignition coil. Turn ignition ON, with the engine OFF. Probe ignition voltage circuit of affected ignition coil with a test light that is connected to a good ground. See Fig 1 -Fig 8 . Does the test light illuminate? If yes, go to next step. If no, go to step  19 .
  9. Probe ignition voltage circuit at affected ignition coil with a test light that is connected to the ground circuit of affected ignition coil. Does the test light illuminate? If yes, go to next step. If no, go to step  20 .
  10. Probe ignition voltage circuit at affected ignition coil with a test light that is connected to low reference circuit of affected ignition coil. Does the test light illuminate? If yes, go to next step. If no, go to Step  15 .
  11. Measure resistance of ignition voltage circuit of affected ignition coil from fuse that supplies ignition voltage to affected ignition coil to harness connector of affected ignition coil. Is resistance less than 3 ohms? If yes, go to next step. If no, go to step  19 .
  12. Measure resistance of ground circuit of affected ignition coil from harness connector of affected ignition coil to a good ground. Is resistance less than 3 ohms? If yes, go to step  17 . If no, go to step  20 .
  13. Turn ignition ON, with the engine OFF. Disconnect Crankshaft Position (CKP) sensor. Measure voltage from CKP sensor 12-volt reference circuit to a good ground with DVOM. Compare measured voltage with system voltage. Is difference in voltage more than 0.5 V? If yes, go to next step. If no, go to step  16 .
  14. Test for a short to ground in CKP 12-volt reference circuit or Camshaft Position (CMP) sensor 12-volt reference circuit. Did you find and correct the condition? Repair as necessary. After repair is completed, go to step  26 . If circuit test okay, go to step  18 .
  15. Test low reference circuit of ignition coil for an open or high resistance. Repair as necessary. After repair is completed, go to step  26 . If circuit test okay, go to step  18 .
  16. Test for shorted terminals and poor connections at CKP sensor. Repair as necessary. After repair is completed, go to step  26 . If terminals and connections test okay, go to step  21 .
  17. Test for an intermittent and for a poor connections at the ignition coil. Repair as necessary. After repair is completed, go to step  26 . If no problem is found, go to step  24 .
  18. Test for shorted terminals and for poor connections at the Powertrain Control Module (PCM). Repair as necessary. After repair is completed, go to step  26 . If no problem found, go to step  25 .
  19. Repair ignition voltage circuit of affected ignition coil for an open, high resistance or a short to ground. After repair is completed, go to step  26 .
  20. Repair ground circuit of affected ignition coil for an open or high resistance. After repair is completed, go to step  26 .
  21. Replace CKP sensor. See CRANKSHAFT POSITION SENSOR under SENSORS in REMOVAL & INSTALLATION - CORVETTE article. After repair is completed, go to step  26 .
  22. Replace the spark plug. After repair is completed, go to step  26 .
  23. Replace the spark plug wire. After repair is completed, go to step  26 .
  24. Replace the ignition coil. See IGNITION COILS under IGNITION SYSTEMS in REMOVAL & INSTALLATION - CORVETTE article. After repair is completed, go to step  26 .
  25. Replace the PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - CORVETTE article. After repair is completed, go to step  26 .
  26. Turn engine OFF for 30 seconds. Start engine and operate vehicle. Observe vehicle performance and driveability. Does vehicle operate normally? If yes, system is okay. If no, go to step  3 .
Fig 1: Identifying Ignition Coil 1 Connector Terminals
G00250932Courtesy of GENERAL MOTORS CORP.
Fig 2: Identifying Ignition Coil 2 Connector Terminals
G00250933Courtesy of GENERAL MOTORS CORP.
Fig 3: Identifying Ignition Coil 3 Connector Terminals
G00250934Courtesy of GENERAL MOTORS CORP.
Fig 4: Identifying Ignition Coil 4 Connector Terminals
G00250935Courtesy of GENERAL MOTORS CORP.
Fig 5: Identifying Ignition Coil 5 Connector Terminals
G00250936Courtesy of GENERAL MOTORS CORP.
Fig 6: Identifying Ignition Coil 6 Connector Terminals
G00250937Courtesy of GENERAL MOTORS CORP.
Fig 7: Identifying Ignition Coil 7 Connector Terminals
G00250938Courtesy of GENERAL MOTORS CORP.
Fig 8: Identifying Ignition Coil 8 Connector Terminals
G00250939Courtesy of GENERAL MOTORS CORP.
scientia non olet · About LEMON Manuals