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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 250 (Automatic Transmission - 6L50/6L80/6L90 - DTC P0218 To DTC P0971) >> DTC P0776 or P0777 >> Diagnostic Fault Information

Diagnostic Fault Information

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The following fault table will help determine if a hydraulic circuit or an incorrect position of a valve train component affects the transmission operation.

Component Cause DTCs
1-2-3-4 and 3-5-R Clutch Housing Assembly 1-2-3-4 clutch backing plate retaining ring not seated, causing the piston to over-travel and cut 1-2-3-4 clutch piston seal P0776
P0777
4-5-6 Clutch Housing 4-5-6 Housing broken hub weld P0776
Control Solenoid (w/body and TCM) Valve Assembly
  • Clutch pressure control solenoid 2:
    • Always exhausting (Stuck On)
    • Not exhausting (Stuck Off)
    • Needle piston or armature pin binding
    • Control signal fluid supply leak - valve body filter plate assembly cracked or damaged gasket seal
    • O-ring seals leaking
  • Valve body filter plate assembly cracked, blocked or damaged gasket seal
 P0776
P0777
Fluid Pump Cover Assembly Fluid pump cover vanes and fluid pump rotor broken - wrong pump rotor installed P0776
Fluid Pump Cover Assembly Isolator valve sticking or stuck - debris, sediment, binding or scored bore P0776
P0777
Upper Control Valve Body 3-5-R regulator valve stuck - debris, sediment, binding or scored bore P0776
Upper Control Valve Body
  • Actuator feed limit circuit supply fluid to solenoid restricted or not available (debris or sediment blockage)
  • B-R-1 and 4-5-6 clutch regulator valve not in the applied position - debris, sediment, binding or scored
  • 4-5-6 clutch boost valve not exhausting - binding or scored bore
 P0776
P0777
Upper Control Valve Body The B-2-6 regulator valve stuck - debris, sediment, binding or scored bore P0777
Transmission Gear Range to PC Solenoid Valve Operation

Gear 1-2-3-4 CL PC SOL 5 2-6 CL PC SOL 4 3-5 REV CL PC SOL 2 LOW REV 4-5-6 CL PC SOL 3
Park OFF OFF OFF ON
Reverse OFF OFF ON ON
Neutral OFF OFF OFF ON
1st Braking ON OFF OFF ON
1st ON OFF OFF OFF
2nd ON ON OFF OFF
3rd ON OFF ON OFF
4th ON OFF OFF ON
5th OFF OFF ON ON
6th OFF ON OFF ON
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