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Ignition System (Corvette)

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
  2. Turn ignition on with engine off. Using test light connected to ground, probe terminals of the following fuses, located in underhood electrical center No. 2.
    • A/C
    • ENG IGN1
    • INJR1
    • INJR2
    • THROT CONT

    If test light illuminates on both sides of all fuses, go to next step. If test light does not illuminate, diagnose ignition relay circuit. See IGNITION RELAY CIRCUIT (5.7L)  under BASIC IGNITION SYSTEM CHECKS.

  3. Using scan tool, check for Diagnostic Trouble Codes (DTCs). If any DTCs related to Throttle Actuator Control (TAC) system are present, diagnose DTC. See appropriate SELF-DIAGNOSTICS article. If DTCs are not present, go to next step.
  4. Using scan tool, check for DTCs. If any DTCs related to vehicle theft deterrent system are present, this indicates a problem with column lock or VTD fuel enable circuit. See appropriate BODY CONTROL MODULE article in ACCESSORIES & EQUIPMENT. If DTCs P0230, P0335, P0336, P0601, P0602, P0604 or P0606 are present, diagnose DTCs. See appropriate SELF-DIAGNOSTICS article. If DTCs are not present, go to next step.
  5. Using scan tool, monitor engine speed while cranking engine. If engine RPM is indicated on scan tool, go to step  9 . If engine RPM is not indicated on scan tool, go to next step.
  6. Disconnect Crankshaft Position (CKP) sensor harness connector. Using DVOM, measure voltage at ignition feed circuit at CKP sensor harness connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If voltage is about battery voltage, go to step  13 . If voltage is not about battery voltage, go to next step.
  7. Disconnect Camshaft Position (CMP) sensor harness connector. Using DVOM, measure voltage at ignition feed circuit at CMP sensor harness connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If voltage is about battery voltage, go to step  14 . If voltage is not about battery voltage, go to next step.
  8. Check for short to ground in CKP sensor ignition feed circuit and CMP sensor ignition feed circuit. Repair as necessary. After repairs, go to step  16 . If circuits are okay, go to step  15 .
  9. Using scan tool, monitor engine coolant temperature. If scan tool value is close to actual value (ambient temperature), go to next step. If scan tool value is not close to actual value, go to DTC P0118. See appropriate SELF-DIAGNOSTICS article.
  10. Using scan tool, command fuel pump on. If fuel pump operates, go to next step. If fuel pump does not operate, diagnose fuel pump relay circuit. See FUEL SYSTEM ELECTRICAL CIRCUIT (CORVETTE)  .
  11. Turn ignition off. Install fuel pressure gauge. Turn ignition on with engine off and observe fuel pressure. Fuel pressure should be 55-61 psi (3.8-4.2 kg/cm2 ). If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, diagnose fuel system. See BASIC FUEL SYSTEM CHECKS  .
  12. Check for air leaks in ducts between Mass Airflow (MAF) sensor and throttle body. A faulty MAF sensor may cause a no-start or stalling after start condition. Disconnecting MAF sensor will cause PCM to default to speed density (MAP, IAT, RPM) to calculate load and intake airflow. If fault condition is corrected by disconnecting MAF sensor, or connections are okay, replace MAF sensor. Check if spark plugs are gas fouled by a rich condition. Check for engine mechanical failure causing a no-start condition (i.e. timing chain, low compression, etc.). Compare MAP/BARO parameters to a similar vehicle and ensure values are similar. If a problem is found and repaired, go to step  16 . If no problem is found, see appropriate TROUBLE SHOOTING - NO CODES article.
  13. Replace CKP sensor. After replacing CKP sensor, go to step  16 .
  14. Replace CMP sensor. After replacing CMP sensor, go to step  16 .
  15. Replace PCM. Perform PCM relearn procedures. After replacing PCM, go to next step.
  16. Using scan tool, select DTC, and then CLEAR INFO function. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and stalls, go to step  2 .
  17. Allow engine to idle until normal operating temperature is reached. Using scan tool, select DTC, and then FAIL THIS IGN function. If any DTCs are present, diagnose DTCs. See appropriate SELF-DIAGNOSTICS article. If DTCs are not present, go to next step.
  18. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any DTCs are present, diagnose DTCs. See appropriate SELF-DIAGNOSTICS article. If DTCs are not present, system is okay.
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