GM Service Manual Online
For 1990-2009 cars only

No 2-3 Upshift

Checks

Causes

Shift solenoid B

Refer to Diagnostic System Check - Vehicle.

Shift switch

Refer to Diagnostic System Check - Vehicle.

Transmission control module (TCM)

Refer to Diagnostic System Check - Vehicle.

Line pressure out of range

Operation of the control valve spool

Line pressure in range

Burn or wear of the clutch. Refer to High Clutch Disassemble.