GM Service Manual Online
For 1990-2009 cars only

Checks

Causes

Line pressure solenoid

Refer to DTC 48 .

Transmission fluid level

Refer to Transmission Fluid Check .

Select linkage

Refer Park/Neutral Position Switch Replacement .

Throttle angle

Throttle angle out of adjustment. Refer to Symptoms - Engine Controls .

Low 1-way clutch

Burn or wear of the low clutch. Refer to Low Clutch Disassemble .

Control

Control valve spool error