DTC P2820 or P2821

Automatic Transmission - 10L80 MHS MQC | Diagnostic Information and Procedures | Document ID: 5369092 Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC P2820 Transmission Control Solenoid Valve 9 Stuck Off DTC P2821 Transmission Control Solenoid Valve 9 Stuck On Diagnostic Fault Information

Note

DTC P2820 will set with a hydraulic/mechanical condition or high resistance in the circuit of the component Q77J without setting component/control circuit DTCs. DTC P2821 will set with a hydraulic/mechanical condition. The components are listed from the least to the most intrusive to service.

Component	DTC	Condition
Q77J Transmission Control Solenoid Valve 9	P2820, P2821	Binding or Sticking Mechanically damaged Missing components
Default Disable Valve Valve Body Bore Valve Spring	P2820, P2821	Binding or Sticking Debris on the component. Mechanically damaged
Default Select Valve Valve Body Bore Valve Spring	P2820, P2821	Binding or Sticking Debris on the component. Mechanically damaged
Control Valve Body	P2820, P2821	Fluid/oil passage — Restricted / Leaking

Circuit/System Description For an overview of the component/system, refer to: Park - Engine Running Park - Engine Running Reverse Neutral - Engine Running Drive Range, First Gear Drive Range, Second Gear Drive Range, Third Gear Drive Range, Fourth Gear Drive Range, Fifth Gear Drive Range, Sixth Gear Drive Range, Seventh Gear Drive Range, Eighth Gear Drive Range, Ninth Gear Drive Range, Tenth Gear Electronic Component Description Conditions for Running the DTC DTC P126C, P2534, P2820, P2821 = Not set DTCs related to the following system/component = Not Set – B14A Automatic Transmission Output Speed Sensor – B14C Automatic Transmission Input Speed Sensor – B14DA Automatic Transmission Intermediate Speed Sensor 1 – B14DB Automatic Transmission Intermediate Speed Sensor 2 – B26 Crankshaft Position Sensor – B303 Transmission Range Sensor – Q77A Transmission Control Solenoid Valve 1 – Q77B Transmission Control Solenoid Valve 2 – Q77C Transmission Control Solenoid Valve 3 – Q77D Transmission Control Solenoid Valve 4 – Q77E Transmission Control Solenoid Valve 5 Battery Voltage = Greater than 9 V Engine Speed = Greater than 499 RPM High Side Driver 1, 2 = On Ignition and Start Signal = 9 to 32 V Ignition and Start Switch Signal = On Transmission Service Fast Learn = Disabled Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC Gear Ratio = Incorrect Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type A DTC — Additional actions taken: Autostart/Autostop = Disabled Grade braking = Disabled High Side Driver 1 = Disabled Manual Shift Control = Disabled Neutral Idle Mode = Disabled Powertrain braking = Disabled Tap Up & Tap Down = Disabled TCC Control = Disabled Transmission Adaptive Pressure Control = Freeze current adapt values Transmission gear allowed = 2, 7 Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type A DTC Diagnostic Aids High resistance in the circuits of the component Q77J may set DTC P2820 without setting control circuit DTC(s). Reference Information DTC Type Reference Powertrain Diagnostic Trouble Code (DTC) Type Definitions Scan Tool Reference Control Module References Circuit/System Verification

1. Verify the condition does not exist: Incorrect fluid level or condition » Refer to: Transmission Fluid Level and Condition Check ⇒ If a condition exists Repair or replace as necessary ⇓ If no condition exists
2. Ignition » On / Vehicle » In Service Mode
3. Perform the following action: Clear the DTCs.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data. Refer to: Road Test Verify that no DTC listed in the DTC Descriptor Category is set. ⇒ If any DTC listed in the DTC Descriptor Category is set Refer to: Diagnostic Fault Information & Verify the conditions listed in the table do not exist ⇓ If none of the DTCs listed in the DTC Descriptor Category is set
5. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Automatic Transmission Fluid, Fluid Pan and/or Filter Replacement Control Valve Body Replacement Torque Converter Diagnosis Torque Converter Replacement For control module replacement, programming, and setup refer to: Control Module References Additional Procedures Transmission Service Fast Learn Procedure — Perform only when the component/system is serviced.