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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 214 (Automatic Transaxle Diagnosis - 4T65-E) >> Diagnostic Tests >> DTC P0753: 1-2 Shift Solenoid Electrical Problem >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Buick Regal and 2003 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 DTCs. Are DTCs P0758 or P1860 also set? If so, go to next step. If not, go to step  9 .
  3. Inspect the fuse in the ignition "1" voltage circuit for an open. Replace the fuse if necessary. Was the fuse open? If so, go to next step. If not, go to step  7 .
  4. Test the ignition "1" voltage circuit (CKT 1039) of the 1-2 shift solenoid valve for a short to ground between the fuse block and the transaxle in-line 20-pin connector. Did you find and correct the condition? If so, go to step  20 . If not, go to next step.
    NOTE: The condition that affects this circuit may exist in other connecting branches of the circuit.
  5. Disconnect the transaxle internal wiring harness from the 1-2 shift solenoid valve, the 2-3 shift solenoid valve and the TCC PWM solenoid valve. Test the ignition "1" voltage circuit (CKT 839) of the 1-2 shift solenoid valve for a short to ground between the transaxle in-line 20-pin connector and the solenoids. Did you find the condition? If so, go to step  17 . If not, go to next step.
    NOTE: The condition that affects this circuit may exist in other connecting branches of the circuit.
  6. Test the 1-2 shift solenoid valve, the 2-3 shift solenoid valve and the TCC PWM solenoid valve for a short to ground between the ignition "1" voltage side of each solenoid and the transaxle case. Replace any faulty solenoid. See REMOVAL & INSTALLATION in SERVICING - CENTURY & REGAL article. Did you complete the replacement? If so, go to step  20 .
  7. Test the ignition "1" voltage circuit (CKT 1039) of the 1-2 shift solenoid valve for an open between the fuse block and the transaxle in-line 20-pin connector. Did you find and correct the condition? If so, go to step  20 . If not, go to next step.
  8. Test the ignition "1" voltage circuit (CKT 839) of the 1-2 shift solenoid valve for an open between the transaxle in-line 20-pin connector and the solenoid. Did you find the condition? If so, go to step  17 . If not, see INTERMITTENT CONDITIONS in the appropriate ENGINE PERFORMANCE article.
  9. Turn ignition OFF. Disconnect the transaxle in-line 20-pin harness connector (additional DTCs may set). Install the Jumper Harness (J 44152) on the engine side of the transaxle in-line 20-pin connector. Using the Connector Test Adapter Kit (J 35616-A), connect a test lamp from terminal "A" to terminal "E" of the jumper harness. Turn ignition ON, engine OFF. With a scan tool, command the 1-2 shift solenoid valve ON and OFF three times. Does the test lamp turn ON and OFF? If so, go to step  12 . If not, go to next step.
  10. Test the ignition "1" voltage circuit (CKT 1039) of the 1-2 shift solenoid valve for an open between the fuse block and the transaxle in-line 20-pin connector. Did you find and correct the condition? If so, go to step  20 . If not, go to next step.
  11. Test the control circuit (CKT 1222) of the 1-2 shift solenoid valve for an open, short to ground or short to power between the PCM and the transaxle in-line 20-pin connector. Did you find and correct the condition? If so, go to step  20 . If not, go to step  19 .
  12. Connect the jumper harness to the transaxle side of the transaxle in-line 20-pin connector. Using a DMM, measure the resistance of the 1-2 shift solenoid valve circuit between terminals "A" and "E" of the jumper harness. Does the resistance measure within 19-31 ohms? If so, go to next step. If not, go to step  16 .
  13. Measure the resistance from terminals "A" and "E" to the transaxle case. Are both readings greater than 10 k/ohms? If so, see go to next step. If not, go to step  15 .
  14. Measure the resistance from terminal A and all other terminals of the A/T inline 20-pin connector. Did you find a condition of 10 k/ohms? If so, go to step  16 . If not, go to INTERMITTENT CONDITIONS in the appropriate ENGINE PERFORMANCE article.
  15. Disconnect the harness at the solenoid. Measure the resistance from each terminal of the solenoid to the transaxle case. Are both readings greater than 10 k/ohms? If so, go to step  17 . If not, go to step  18 .
  16. Disconnect the harness from the 1-2 shift solenoid valve. Measure the resistance of the solenoid. Is the resistance within 19-31 ohms? If so, go to next step. If not, go to step  18 .
  17. 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  20 .
  18. Replace the 1-2 shift solenoid valve. See REMOVAL & INSTALLATION in SERVICING - CENTURY & REGAL article. Did you complete the replacement? If so, go to step  20 .
  19. Replace the PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to next step.
  20. Perform the following procedure to verify the repair:
    • Select DTC.
    • Select Clear Info.
    • Drive the vehicle in D4 until the transaxle shifts to 2nd gear and maintain speed for at least 5 seconds.
    • Ensure that the gear ratios are as specified for 1st and 2nd gear.
    • Select SPECIFIC DTC.
    • Enter DTC P0753.

    Has the test run and passed? If so, go to next step. If not, go to step  2 .

  21. With a scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? If so, go to appropriate ENGINE PERFORMANCE article. If not, the system is OK.
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