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Home >> Saturn >> 2000 >> LS Automatic >> Repair and Diagnosis (Single Page) >> Transmission >> Automatic Trans >> Automatic Transaxle Diagnosis - 4T40-E & 4T45-E >> Diagnostic Tests >> DTC P0751: 1-2 Shift Solenoid Performance (No 1ST Or 4TH Gear) >> Diagnostic Procedure

Diagnostic Procedure

NOTE: For connector end views and component locations, see Figure -Figure . For circuit locations, see WIRING DIAGRAMS  .
  1. Perform OBD system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under DIAGNOSIS & TESTING. After performing OBD system check, go to next step.
  2. Check transaxle fluid level. Fill if necessary. See appropriate AUTOMATIC TRANSMISSION SERVICING article in TRANSMISSION SERVICING. Go to next step.
  3. Connect scan tool to DLC. Turn ignition switch to ON position. Using scan tool, record freeze frame and failure records for reference. Clear DTC. Use scan tool snapshot mode to record current gear and gear ratio. Drive vehicle in "D" position, to obtain 1-2, 2-3 and 3-4 shifts with throttle position angle of more than 8 percent. When current gear is 2nd, if gear ratio is 2.87:1-3.13:1, go to step  5 . If gear ratio is not 2.87:1-3.13:1, go to next step.
  4. When current gear is 1st, if gear ratio is 1.54:1-1.71:1, go to step  6 . If gear ratio is not 1.54:1-1.71:1, go to next step.
  5. When current gear is 3rd, if gear ratio is 0.61:1-0.72:1, go to step  7 . If gear ratio is not 0.61:1-0.72:1, go to next step.
  6. When current gear is 4th, if gear ratio is 0.91:1-1.07:1, go to step  8 .
  7. Inspect 1-2 shift circuit for the following conditions: 1-2 shift solenoid valve mechanically stuck on. 1-2 shift valve stuck in applied position. Repair as necessary. See HYDRA-MATIC 4T40-E & 4T45-E OVERHAUL article. After repairs, go to step  9 .
  8. Inspect 1-2 shift circuit for the following conditions: 1-2 shift solenoid valve mechanically stuck off. Damaged 1-2 shift solenoid valve "O" ring. 1-2 shift valve stuck in released position. See HYDRA-MATIC 4T40-E & 4T45-E OVERHAUL article. After repairs, go to next step.
  9. After repair is complete, select DTC on scan tool. Select CLEAR INFO function. Select SPECIFIC DTC and enter DTC "P0751". Drive vehicle in "D" position. Allow transaxle to shift through all gears. Actual gear ratios must match commanded gears for .75 seconds for all gears. If DTC P0751 is not present, repair is complete. If DTC P0751 is still present, repeat test.
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