4T65-E - Automatic Transmission
DTC P1811
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provide an overview of each diagnostic category.
DTC Descriptor
DTC P1811
- Maximum Adapt and Long Shift
Circuit/System Description
The transmission pressure is modified by an adaptive modifier, which controls the shift execution time. The powertrain control module (PCM) monitors the time required to accomplish the shift. If the shift takes longer than 0.65 second and the adaptive modifier cannot shorten this time, then a counter increases by 1.
Conditions for Running the DTC
The shift is adaptable.
Conditions for Setting the DTC
The 1-2, 2-3, or 3-4 shift is longer than 0.65 second, twice in 1 trip.
Action Taken When the DTC Sets
* DTC P1811 is a type C DTC.
* The PCM commands maximum line pressure.
* The PCM freezes transmission adaptive functions.
Conditions for Clearing the DTC
DTC P1811 is a type C DTC.
Diagnostic Aids
DTC P1811 detects shift time that exceeds 0.65 second, indicating increased pressure is needed, but the transmission adaptive pressure (TAP) cell for the shift has already reached maximum value.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (4T65-E - Automatic Transmission)
Connector End View Reference
* Component Connector End Views (Connector End Views By Name)
* Inline Harness Connector End Views (Connector End Views By Number)
Description and Operation Reference
* Transmission General Information (Transmission General Information)
* Transmission General Description (Transmission General Description)
* Transmission Component and System Description (Transmission Component and System Description)
* Electronic Component Description (Electronic Component Description)
* Transmission Adaptive Functions (Transmission Adaptive Functions)
* Automatic Transmission Inline 20-Way Connector Description (Automatic Transmission Inline 20-Way Connector Description)
* Engine Control Module Description (Engine Control Module Description)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information
Special Tools
* J 35616-64B Test Probe
* J 35616-65B Test Probe
* J 44152 Jumper Harness (20 pins)
* J 44257 Main Wiring Harness Connector Remover
Circuit/System Verification
* Ensure the transmission fluid level is at the proper level by performing the Transmission Fluid Level and Condition Check (Transmission Fluid Level and Condition Check). Ensure the line pressure is within specification by performing the Line Pressure Check (Line Pressure Check).
* Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
1. Perform the Line Pressure Check (Line Pressure Check). The pressures should be within specification.
• If the pressures are not within specifications, inspect and repair the following components:
* Oil filter and seal missing, plugged, or damaged-Refer to Automatic Transmission Fluid Filter and Seal Replacement (15. Automatic Transmission Fluid Filter and Seal Replacement).
* Spacer plate and gasket damaged or not assembled correctly-Refer to Control Valve Body and Spacer Plate Assemble (149. Control Valve Body and Spacer Plate Assemble).
* PC solenoid valve damaged or contaminated
* Pressure regulator valve line-up binding or damaged
* Torque signal valve line-up binding or damaged-Refer to Control Valve Body Disassemble (146. Control Valve Body Disassemble).
* Oil pump assembly damaged or missing components-Refer to Transmission Fluid Pump Disassemble (150. Transmission Fluid Pump Disassemble).
2. Using the scan tool, observe the shift times for the 1-2 upshift. The 1-2 shift time should be less than 0.65 second.
• If the shift time is greater than 0.65 second, inspect and repair the following components:
* 1-2 accumulator piston seals rolled or damaged
* 1-2 accumulator piston and pin missing, binding, or damaged-Refer to Accumulator Components Disassemble (157. Accumulator Components Disassemble).
* Forward servo assembly damaged or not assembled correctly-Refer to Forward Servo Removal (47. Forward Servo Removal).
* Oil pump assembly damaged or missing components-Refer to Transmission Fluid Pump Disassemble (150. Transmission Fluid Pump Disassemble).
* Spacer plate and gaskets damaged or not assembled correctly-Refer to Control Valve Body and Spacer Plate Assemble (149. Control Valve Body and Spacer Plate Assemble).
* Driven sprocket support seals damaged or missing-Refer to Driven Sprocket Support Assembly Removal (65. Driven Sprocket Support Assembly Removal).
* Second clutch piston and seal assembly binding or damaged
* Second clutch fiber and steel plates not assembled correctly, burned, or damaged
* Second clutch spring assembly damaged or not assembled correctly-Refer to 2nd Clutch Disassemble (114. 2nd Clutch Disassemble).
* Forward band burned, damaged, or not assembled correctly-Refer to 1-2 Support Drum and Forward Band Removal (73. 1-2 Support Drum and Forward Band Removal).
* 1-2 support roller clutch assembly damaged or not assembled correctly-Refer to 1-2 Support Roller Clutch Disassemble (93. 1-2 Support Roller Clutch Disassemble).
3. Using the scan tool, observe the shift times for the 2-3 upshift. The 2-3 shift time should be less than 0.65 second.
• If the 2-3 shift time is greater than 0.65 second, inspect and repair the following components:
* 2-3 accumulator piston seals rolled or damaged
* 2-3 accumulator piston and pin missing, binding, or damaged-Refer to Accumulator Components Disassemble (157. Accumulator Components Disassemble).
* Oil pump assembly damaged or missing components-Refer to Transmission Fluid Pump Disassemble (150. Transmission Fluid Pump Disassemble).
* Spacer plate and gaskets damaged or not assembled correctly-Refer to Control Valve Body and Spacer Plate Assemble (149. Control Valve Body and Spacer Plate Assemble).
* Driven sprocket support seals damaged or missing-Refer to Driven Sprocket Support Assembly Removal (65. Driven Sprocket Support Assembly Removal).
* Third clutch piston seal rolled or damaged
* Third clutch piston damaged or not assembled correctly
* Third clutch fiber and steel plates not assembled correctly, burned, or damaged
* Third clutch spring assembly damaged or not assembled correctly-Refer to Input and 3rd Clutch Disassemble (105. Input and 3rd Clutch Disassemble).
* Third sprag clutch assembly damaged or not assembled correctly-Refer to Input and 3rd Clutch Pawl Disassemble (102. Input and 3rd Clutch Pawl Disassemble).
4. Using the scan tool, observe the shift times for the 3-4 upshift. The 3-4 shift time should be less than 0.65 second.
• If the 3-4 shift time is greater than 0.65 second, inspect and repair the following components:
* Oil pump assembly damaged or missing components-Refer to Transmission Fluid Pump Disassemble (150. Transmission Fluid Pump Disassemble).
* Spacer plate and gaskets damaged or not assembled correctly-Refer to Control Valve Body and Spacer Plate Assemble (149. Control Valve Body and Spacer Plate Assemble).
* 3-4 accumulator piston seals rolled or damaged
* 3-4 accumulator piston and pin missing, binding, or damaged-Refer to Case Assembly Inspection (76. Case Assembly Inspection).
* Fourth clutch piston seal rolled or damaged
* Fourth clutch piston damaged, not assembled correctly, or seized-Refer to Driven Sprocket Support Assembly Removal (65. Driven Sprocket Support Assembly Removal).
* Fourth clutch fiber and steel plates not assembled correctly, burned, or damaged-Refer to 4th Clutch Components Removal (62. 4th Clutch Components Removal).
* Fourth clutch spring assembly damaged or not assembled correctly-Refer to Driven Sprocket Support Assembly Removal (65. Driven Sprocket Support Assembly Removal).
5. Replace the automatic transmission fluid and filter. Add new automatic transmission fluid. Refer to Transmission Fluid Level and Condition Check (Transmission Fluid Level and Condition Check).
• If the fluid is not at the proper level, add fluid as necessary.
Important: The Reset Transmission Adapts function will clear all adapt cells. This may affect transmission performance. The PCM will update the transmission adapt cell values as the vehicle is driven
6. Perform the Transmission Adapts function.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.