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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1030 (Automatic Transmission - 4L80-E/4L85-E (Troubleshooting)) >> Troubleshooting >> Inaccurate Shift Points

Inaccurate Shift Points

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Inaccurate Shift Points

Checks Cause
AT Output Shaft Speed Sensor Assembly (22)
  • Pinched or broken wire
  • Loose connector
  • Incorrect air gap
  • Inadequate signal
  • Damaged coil
  • Damaged rotor teeth
  • Loose connection
Throttle Position Sensor
  • Pinched or damaged wire
  • Incorrect resistance
  • Loose connector
  • PCM malfunction
AT Fluid Pressure Manual Valve Position Switch Assembly (40)
  • Loose connector
  • Loose bolts causing leakage
  • A pinched wire
  • No signal to the PCM
Axle Ratio Ratio is incorrect or ratio has been changed from its original value.
Tire Size Tire size is incorrect or the size has been changed from its original value.
Check the PCM for current DTCs.