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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 141 (Engine Controls Self-Diagnostics - 5.7L - Bi-Fuel) >> Diagnostic Tests >> DTC P0336: Crankshaft Position Sensor Performance >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, and 2002 Chevrolet Chevy Express. 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. Using the scan tool, establish communication with the PCM, and review DTC information. Is this DTC also stored in the PCM? If yes, see DTC P0336: CRANKSHAFT POSITION SENSOR CIRCUIT under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 5.0L & 5.7L CHEVY EXPRESS & SAVANA. IF no, go to next step.
  3. Crank and attempt to start the engine. Does the engine start and run? If yes, go to next step. If no, go to step  6 .
  4. Using the scan tool, establish communication with the AF ECM. Clear DTC information from the AF ECM. Turn OFF the ignition and wait 10 seconds. Start and idle the engine. Does this DTC set? If yes, go to step  6 . If no, go to next step.
  5. The fault is not present. See DIAGNOSTIC AIDS  . Are any DTCs stored that have not been diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  6. Turn the ignition OFF. Disconnect the PCM connector that contains the engine speed input signal circuit. Remove the engine speed input signal wire and terminal from the PCM connector. Reconnect the PCM connector leaving the signal wire and terminal removed from the connector. Turn the ignition ON while leaving the engine OFF. Observe the engine speed data parameter on the scan tool while communicating with the AF ECM. Using a fused jumper, momentarily ground the engine speed input signal wire and terminal while observing the engine speed data parameter. Does the engine speed data parameter momentarily indicate engine speed when the signal wire is grounded? If yes, go to step  10 . If no, go to next step.
  7. Did the jumper fuse open? If yes, go to next step. If no, go to step  9 .
  8. Test the engine speed signal circuit for a short to voltage condition. Repair wiring as necessary. Was a wiring repair made? If yes, go to step  13 . If no, go to step  11 .
  9. Test the engine speed signal circuit for an open or a short to ground condition. Inspect the AF ECM connector terminals for proper terminal contact. Repair terminal contact or wiring as necessary. Was a terminal or wiring repair made? If yes, go to step  13 . If no, go to step  11 .
  10. Inspect the PCM connector terminals for proper terminal contact. Repair the terminal contact as necessary. Inspect for a condition in which air flow more than 3 gm/s is indicated by the MAF sensor with the ignition ON, and the engine OFF. Was a repair necessary? If yes, go to step  13 . If no, go to step  12 .
  11. Replace AF ECM. See ALTERNATE FUEL ENGINE CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - CHEVY EXPRESS & SAVANA - BI-FUEL. Program (flash) AF ECM with correct vehicle software and calibration. See ALTERNATE FUEL ENGINE CONTROL MODULE  under PROGRAMMING. After repairs, go to step  13 .
    12. NOTE: The following control module replacement procedures must all be completed before attempting to operate the vehicle.
  12. Replace PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL, OVERHAUL & INSTALLATION - CHEVY EXPRESS & SAVANA - GASOLINE. Program (flash) PCM with correct vehicle software and calibration. See POWERTRAIN CONTROL MODULE REPROGRAMMING  under PROGRAMMING. To perform CKP variation learn procedure, a switchover to gasoline operation is necessary. Remove CNG fuse (20-amp) located in underhood fuse block to perform switchover. Perform CKP system variation learn procedure. See CRANKSHAFT POSITION SENSOR SYSTEM VARIATION LEARN PROCEDURE  under PROGRAMMING. After performing repairs and procedures, go to next step.
  13. Using a scan tool, clear the DTC information from both control modules. Operate the vehicle under the Conditions For Running DTC. Using the scan tool parameter DTC STATUS, ensure that this DTC runs. Did this DTC run and pass? If yes, system is okay. If no, go to step  2 .
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