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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 116 (Engine Controls - Self-Diagnostics - 4.0L) >> Diagnostic Tests >> DTC P0385: Crankshaft Position Sensor "B" Circuit >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Oldsmobile Aurora. 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, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Install a scan tool. Attempt to start the engine. Monitor the DTC information with a scan tool. Are DTCs P0335, P0340, and P0385 all set? If yes, go to step  11. If no, go to next step.
    3. NOTE: If DTC P0336 is also set, continue with the diagnostic procedure for DTC P0385 before diagnosing DTC P0336.
  3. Start the engine. Monitor the CKP sensor status parameter with a scan tool. Does the scan tool indicate the CKP sensor status as ANGLE? If yes, go to next step. If no, go to step  5.
  4. With the engine running, manually move the harnesses and connectors that are related to CKP "B" sensor. If the CKP sensor status changes or if an engine stall occurs, locate and repair the condition in the harnesses and/or connectors that are related to CKP "B" sensor. Did you find and correct the condition? If yes, go to step  21. If no, see DIAGNOSTIC AIDS .
  5. Turn the ignition ON, with the engine OFF. Disconnect the CKP sensor "B". Connect the test lamp between the 12-volt reference circuit of the CKP "B" sensor and a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step  8.
  6. Connect the test lamp between the 12-volt reference circuit of the CKP "B" sensor and the low reference circuit of the CKP "B" sensor. Does the test lamp illuminate? If yes, go to next step. If no, go to step  9.
  7. Turn the ignition ON, with the engine OFF. Clear the DTCs with a scan tool. Command the PCM to operate in Time Mode "B" with a scan tool. With the test lamp connected to battery voltage, repeatedly touch the CKP "B" sensor 2 signal circuit in the harness connector. Observe the 24X crank sensor data parameter with a scan tool. Does the scan tool indicate an RPM while touching the test lamp to the signal circuit? If yes, go to step  15. If no, go to step  10.
  8. Turn the ignition OFF. Disconnect the PCM harness connector. Test the 12-volt reference circuit of the CKP "B" sensor for an open. Did you find and correct the condition? If yes, go to step  21. If no, go to step  16.
  9. Turn the ignition OFF. Disconnect the PCM harness connector. Test the low reference circuit of the CKP "B" sensor for an open. Did you find and correct the condition? If yes, go to step  21. If no, go to step  16.
  10. Turn OFF the ignition. Disconnect the PCM harness connector. Turn the ignition ON, with the engine OFF. Test the CKP "B" signal circuit for an open, a short to ground or either CKP low reference, a short to voltage, or a short to the CKP "A" signal circuit. Did you find and correct the condition? If yes, go to step  21. If no, go to step  16.
  11. Disconnect the CMP sensor harness connector. Monitor the 12-volt reference parameter with a scan tool. Does the scan tool display OK? If yes, go to step  17. If no, go to next step.
  12. Raise the vehicle. Disconnect CKP "A" sensor harness connector. Monitor the 12-volt reference parameter with a scan tool. Does the scan tool display OK? If yes, go to step  18. If no, go to next step.
  13. Disconnect the CKP "B" sensor harness connector. Monitor the 12-volt reference parameter with a scan tool. Does the scan tool display OK? If yes, go to step  19. If no, go to next step.
  14. Turn OFF the ignition. Disconnect the PCM harness connectors. Test the 12-volt reference circuit of the CKP "A", the CKP "B", and the CMP sensors for a grounded circuit. Did you find and correct the condition? If yes, go to step  21. If no, go to step  20.
  15. Inspect for poor connections at the harness connector of the CKP "B" sensor. Did you find and correct the condition? If yes, go to step  21. If no, go to step  19.
  16. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step  21. If no, go to step  20.
  17. Replace the CMP sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  21.
  18. Replace the CKP "A" sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  21.
  19. Replace the CKP "B" sensor. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step  21.
  20. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  21. Use the scan tool in order to clear the DTCs. 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.
  22. 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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