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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 103 (Engine Controls Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P0340: Camshaft Position Sensor Circuit - Low Input (SOHC) >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
  2. Install the scan tool. Start and idle the engine. Use a scan tool in order to monitor the CMP active counter. Does the scan tool indicate the CMP active counter is incrementing? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records and data. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observe. See CONDITIONS FOR RUNNING DTC . Does the DTC reset? If yes, go to next step. If no, go to DIAGNOSTIC AIDS .
  4. Turn ignition off. Disconnect CMP sensor harness connector. Turn ignition on, with engine off. Measure the voltage on the CMP 12-volt reference circuit using the Digital Multimeter (DMM) connected to battery ground. Does the voltage measure about B+? If yes, go to step  6. If no, go to next step.
  5. Turn ignition off. Disconnect PCM harness connector C2. Test the 12-volt reference circuit of CMP sensor for short to ground or an open circuit. Did you find and correct the condition? If yes, go to step  16. If no, go to step  12.
  6. Connect a test light to battery positive voltage. Touch the CMP sensor low reference circuit. Does the test light illuminate? If yes, go to step  8. If no, go to next step.
  7. Turn ignition off. Disconnect PCM harness connector C2. Test the low reference circuit of the CMP sensor for an open. Did you find and correct the condition? If yes, go to step  16. If no, go to step  12.
  8. Start engine. Monitor the CAM signal on the scan tool. Connect a 5-amp fused jumper wire to battery positive voltage and momentarily touch the signal circuit 5 times for a duration of 1 second each. Does the CAM signal change EACH time the signal circuit is touched? If yes, go to step  14. If no, go to next step.
  9. Did the fuse in the jumper wire open? If yes, go to step  11. If no, go to next step.
  10. Test the signal circuit of the CMP sensor for a short to voltage or an open. Did you find and correct the condition? If yes, go to step  16. If no, go to step  12.
  11. Test the signal circuit of the CMP sensor for a short to ground. Did you find and correct the condition? If yes, go to step  16. If yes, go to next step.
  12. Inspect for poor connections at the PCM. Did you find and correct the condition? If yes, go to step  16. If no, go to next step.
  13. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL, OVERHAUL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE REPROGRAMMING  under PROGRAMMING. After replacing PCM, go to step  16.
  14. Inspect for poor connections at the CMP sensor. Did you find and correct the condition? If yes, go to step  16. If no, go to next step.
  15. Replace CMP sensor. When complete, go to next step.
  16. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  17. With a scan tool, observe the stored information, Capture Info. 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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