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Home >> Chevrolet >> 2003 >> Corvette Base, 2D Convertible, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics >> Diagnostic Tests >> DTC P0343: CMP Signal High >> Diagnostic Procedures
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Diagnostic Procedures

  1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Connect a scan tool. Start the engine. Use the scan tool in order to monitor the CMP signal input high-to-low and low-to-high transition parameter. Does the scan tool parameter increment? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records for this DTC. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  4. Disconnect PCM. Jumper the CMP sensor low reference circuit from the PCM connector to a good ground. Jumper the CMP sensor 12-volt reference circuit from the PCM connector to battery voltage. Measure the DC duty cycle on the CMP sensor signal circuit at the PCM connector with a DVOM while cranking the engine. Is the duty cycle within 45-55 percent? If yes, go to step  10. If no, go to next step.
  5. Turn ignition OFF. Connect PCM. Remove fuel pump relay. Remove the intake manifold. See appropriate article in ENGINES. Disconnect CMP sensor. Turn ignition ON, with engine OFF. Probe the CMP sensor signal circuit with a test light that is connected to a good ground. Does the test light illuminate? If yes, go to step  7. If no, go to next step.
  6. Turn ignition OFF. Jumper the CMP circuits from the CMP sensor to CMP sensor harness connector. Turn ignition ON, with engine OFF. Measure the voltage drop from the CMP sensor low reference circuit to a good ground. Is the voltage drop more than 0.2 V? If yes, go to step  8. If no, go to step  9.
  7. Test the CMP sensor signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step  15. If no, go to step  10.
  8. Test the CMP sensor low reference circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step  15. If no, go to step  10.
  9. Test for an intermittent and/or poor connections at the CMP sensor. Did you find and correct the condition? If yes, go to step  15. If no, go to step  11.
  10. Test for an intermittent and/or poor connections at the PCM. Did you find and correct the condition? If yes, go to step  15. If no, go to step  14.
  11. Remove CMP sensor. See CAMSHAFT POSITION SENSOR under SENSORS in REMOVAL & INSTALLATION - CORVETTE article. Visually inspect CMP sensor for physical damage and loose or improper installation. Did you find and correct the condition? If yes, go to step  15. If no, go to next step.
  12. Visually inspect CMP sensor reluctor wheel for damage. If the CMP reluctor wheel is damaged, replace camshaft. See appropriate article in ENGINES. Did you find and correct the condition? If yes, go to step  15. If no, go to next step.
  13. Replace CMP sensor. See CAMSHAFT POSITION SENSOR under SENSORS in REMOVAL & INSTALLATION - CORVETTE article. Did you complete the replacement? If yes, go to step  15.
  14. Replace PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - CORVETTE article. Did you complete the replacement? If yes, go to next step.
  15. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition cycle? If yes, go to  2. If no, go to next step.
  16. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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