GM Service Manual Online
For 1990-2009 cars only

Checks

Cause

DEFINITION: Transmission main line pressure that is determined to be high or low. Refer to Line Pressure Check .

Automatic Transmission Fluid Level - low pressure only

Low fluid level

Thermo Element Assembly - low pressure only

    • The thermo element plate pins (120, 123) are misadjusted.
    • The thermo element (121) or the thermo element plate (122) is out of position, missing, or damaged -- causing low fluid level in the oil pan.

Oil Filter and Seal Assembly

    • The oil filter assembly (100) is missing or damaged.
    • The oil filter seal assembly (101) is missing or damaged, low pressure only.

Wiring Harness Assembly

The wiring harness assembly (224) is disconnected or damaged.

Oil Pump Assembly

    • The following components are worn or damaged - low pressure only:
       - The oil pump cover (201)
       - The oil pump body (202)
       - The oil pump vane ring (209)
       - The oil pump rotor (210)
       - The oil pump vanes (211)
       - The oil pump slide oil seal ring (212)
       - The oil pump slide O-ring seal (213)
       - The oil pump slide (214)
    • The oil pump slide (214) is binding, high pressure only.
    • The oil pump prime springs (222, 223) or the oil pump slide pivot pin (215) is missing or damaged, low pressure only.
    • The oil pump slide seal (220) or the oil pump slide seal support (221) is missing or damaged, high pressure only.

Pressure Control Solenoid Valve Assembly

    • The pressure control solenoid valve assembly (322) is damaged.
    • The solenoid valve O-ring seals (305, 316) are missing or damaged.
    • The valve retainer (314) is missing or damaged.

Torque Signal Regulator Valve Assembly

    • The torque signal regulator valve (321) is binding or damaged.
    • The valve retainer (314) is missing or damaged.

Pressure Regulator Valve Assembly

    • The pressure regulator valve (313) is binding or is damaged.
    • The pressure regulator valve springs (311, 312) is missing or damaged.
    • The reverse boost valve (310) is binding or is damaged, high pressure only.
    • The line boost valve (304) is binding or is damaged, high pressure only.
    • The valve retainer (302) is missing or is damaged.

Actuator Feed Limit Valve Assembly - low pressure only

    • The actuator feed limit valve (414) is binding or is damaged.
    • The actuator feed limit valve spring (415) is missing or is damaged.
    • The actuator feed limit valve spring retainer (416) is missing or damaged.

Low Blow Off Valve Assembly - low pressure only

    • The low blow off valve spring (323) is missing or is damaged.
    • The low blow off ball valve (324) is missing, binding, or is damaged.
    • The low blow off valve spring retainer (325) is missing or is damaged.