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Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 73 (Engine Controls Self-Diagnostics - 5.7L Corvette) >> Diagnostic Tests >> DTC P0343: CMP Signal High >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
  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 DTC, or as closely as possible to the conditions recorded in the Freeze Frame/Failure Records. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  4. Disconnect both PCM connectors. Locate the PCM connector C1 on the sensor side. Use a jumper wire in order to connect the low reference circuit of the CMP sensor to a known-good ground. Locate the PCM connector C2 on the sensor side. Use a fused jumper wire in order to connect the 12-volt reference circuit of the CMP sensor to battery voltage. Probe the CMP sensor signal circuit with one lead of the Digital Multimeter (DMM), and connect the other lead to a ground. Select the duty cycle option on the DMM. Crank the engine. Is the duty cycle 45-55%? If yes, go to step  17. If no, go to next step.
  5. Turn OFF the ignition. Connect the PCM connectors. Remove the intake manifold in order to access the CMP sensor. Disconnect the CMP sensor electrical connector. Turn ON the ignition, with the engine OFF. Use the DMM in order to measure the voltage from the 12-volt reference circuit of the CMP sensor to the battery ground. Does the DMM display battery voltage? If yes, go to next step. If no, go to step  8.
  6. Use a DMM in order to measure the voltage of the CMP sensor from the 12-volt reference circuit to the low reference circuit. Does the DMM display battery voltage? If yes, go to step  9. If no, go to next step.
  7. Test for an open in the low reference circuit of the CMP sensor. Did you find an open low reference circuit? If yes, go to step  13. If no, go to step  17.
  8. Test for an open or for a short to ground in the 12-volt reference circuit of the CMP sensor. Did you find the circuit open or shorted to a ground? If yes, go to step  12. If no, go to step  17.
  9. Turn ON the ignition, with the engine OFF. Use a DMM in order to measure the voltage at the CMP sensor signal circuit to ground with the DMM. Is the voltage less than 1 V? If yes, go to next step. If no, go to step  14.
  10. Probe the CMP signal with a test lamp connected to battery voltage. Does the test lamp illuminate? If yes, go to step  15. If no, go to next step.
  11. Turn OFF the ignition. Disconnect the PCM connector C1. Use the DMM in order to test the continuity of the signal circuit from the sensor harness connector to the PCM. Is the resistance less than 2 ohms? If yes, go to step  18. If no, go to step  16.
  12. Repair the open, or repair the short to ground in the 12-volt reference circuit of the CMP sensor. After repairs, go to step  20.
  13. Repair an open in the CMP low reference circuit. After repairs, go to step  20.
  14. Repair the short to voltage in the CMP sensor signal circuit. After repairs, go to step  20.
  15. Repair the short to ground in the CMP sensor signal circuit. After repairs, go to step  20.
  16. Repair the open in the CMP sensor signal circuit. After repairs, go to step  20.
  17. Inspect the PCM harness connector for poor connections. If you find a poor connection, repair the connector as necessary. Did you find and correct the condition? If yes, go to step  20. If no, go to step  19.
  18. Replace the CMP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  20.
  19. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  20. 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 DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  21. Observe the stored information, Capture Info with a scan tool. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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