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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 P1887: Torque Converter Clutch Release Switch Circuit Malfunction >> 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. Install a scan tool. Turn ignition on, engine off. Before clearing the DTCs, use the scan tool to record the freeze frame and failure records for reference. Using the CLEAR INFO function will erase the stored freeze frame and failure records from the PCM. Record the freeze frame and failure records. Clear the DTC. With the scan tool, observe the TCC release pressure parameter. Does the scan tool indicate YES for the TCC release pressure parameter? If so, go to next step. If not, go to step  6 .
  3. Turn ignition off. Disconnect the transaxle in-line 20-way connector (additional DTCs may set). Connect the Jumper Harness (J 44152) on the engine side of the 20-way connector. Using the Connector Test Adapter Kit (J 35616-A), connect a fused jumper wire from terminal "U" to a good ground. Turn ignition on, engine off. Observe the TCC release pressure parameter. Does the scan tool indicate YES for the TCC release pressure parameter? If so, go to next step. If not, go to step  5 .
  4. Test the signal circuit (CKT 657) of the TCC release switch for an open between the PCM connector and the transaxle in-line 20-way connector. Did you find and correct a condition? If so, go to step  11 . If not, go to step  10 .
  5. Test the signal circuit (CKT 1804) of the TCC release switch for an open between the transaxle in-line 20-way connector and the TFP manual valve position switch. Did you find a condition? If so, go to step  8 . If not, go to step  9 .
  6. Using the scan tool, observe TCC slip speed and TCC release pressure. Drive the vehicle with the range selector in D4 until the TCC is applied and slip speed is below 50 RPM. Does the scan tool indicate YES for the TCC release pressure parameter? If so, go to next step. If not, see DIAGNOSTIC AIDS  .
  7. Inspect for the following conditions of mechanical components and hydraulic circuits that could cause TCC release pressure at the TCC release switch when the TCC is applied:
    • The turbine shaft "O" ring seal leaking.
    • The turbine shaft oil seal rings missing or damaged.
    • The TCC control valve damaged.
    • The No. 1 check ball damaged.
    • The spacer plate release exhaust blocked with debris.
    • The case cover or spacer plate gaskets improperly installed.

    See appropriate OVERHAUL article. Did you complete the repair? If so, go to step  11 .

  8. Replace the transaxle internal wiring harness assembly. See TRANSAXLE INTERNAL WIRING HARNESS  under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to step  11 .
  9. Replace the TFP manual valve position switch. See TRANSMISSION FLUID PRESSURE MANUAL VALVE POSITION SWITCH  under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to step  11 .
  10. Replace the PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to next step.
  11. Perform the following procedure to verify the repair:
    • Select DTC.
    • Select CLEAR INFO.
    • Drive the vehicle in D4 until the transaxle shifts to 4th gear and the TCC is commanded on.
    • Observe TCC release pressure on the scan tool.
    • The TCC release pressure status must indicate NO for at least 3 seconds.
    • Select SPECIFIC DTC.
    • Enter DTC P1887.

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

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