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Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 35 (Automatic Transaxle Diagnosis - 4T65-E) >> Diagnostic Tests >> DTC P0730: Incorrect Gear Ratio >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Buick Regal, 2002 Buick Century, 2001 Buick Regal, and 2001 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the diagnostic system check? If so, go to next step. If not, see DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM.
  2. Visually inspect the transaxle cooling system for fluid leaks. Did you find the condition? If so, go to step  7 . If not, go to next step.
  3. Did you perform the transmission fluid checking procedure? If so, go to next step. If not, perform the transmission fluid checking procedure. See appropriate AUTOMATIC article in TRANSMISSION SERVICING.
  4. Install a scan tool. Start the engine. Before clearing the DTCs, use the scan tool to record the failure records for reference. Using the CLEAR INFO function will erase the stored failure records from the PCM. Record the failure records. Clear the DTCs. Using the scan tool, select CURRENT GEAR and GEAR RATIO. Drive the vehicle in gear ranges 1, 2, 3, 4 and Reverse with the throttle angle greater than 14 percent. Record the gear ratio for each gear. Was each gear ratio within the specified ranges?
    • Reverse: 2.33:1 to 2.43:1
    • 1st: 2.87:1 to 2.97:1
    • 2nd: 1.52:1 to 1.62:1
    • 3rd: 0.95:1 to 1.05:1
    • 4th: 0.65:1 to 0.75:1

    If so, see DIAGNOSTIC AIDS  . If not, go to next step.

  5. Perform the line pressure check. See HYDRAULIC PRESSURE TESTS  under PERFORMANCE TESTS. Did you find the condition? If so, see SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING. If not, go to next step.
  6. Inspect for clutch slippage. See SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING. Did you complete the repair? If so, go to step  8 .
  7. Repair the transaxle cooling system as necessary. Did you complete the repair? If so, go to next step.
    8. NOTE: The CLEAR TAPS function will clear all adapt cells. This may affect transaxle performance. The PCM will update the transaxle adapt cell values as the vehicle is driven.
  8. Change the transmission fluid and filter. See appropriate AUTOMATIC article in TRANSMISSION SERVICING. Using the scan tool, perform the CLEAR TAPS function. Did you complete the above procedure? If so, go to next step.
  9. Perform the following procedure to verify the repair:
    • Select DTC.
    • Select CLEAR INFO.
    • Start the engine and let the engine run until the transmission fluid temperature is greater than 68°F (20°C).
    • Drive the vehicle with the throttle angle greater than 14 percent and the vehicle speed greater than 5 MPH.
    • Ensure that any one of the gear ratio values are obtained for at least 7 seconds.
    • Select SPECIFIC DTC.
    • Enter DTC P0730.

    Has the test run and passed? If so, system is okay. If not, go to step  1 .

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