The transmission pressure is modified by an adaptive modifier, which controls the shift execution time. This diagnostic tests 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.

The 1-2, 2-3, or 3-4 shift is longer than 0.65 second, twice in 1 trip.

DTC P1811 is a type C DTC.

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Electrical Information Reference

Scan Tool Reference

DTC Type Reference

Ensure the transmission fluid level is at the proper level by performing the Transmission Fluid Check . Ensure the line pressure is within specification by performing the Line Pressure Check .

1. Perform the Transmission Fluid Check .

⇒	If the level is not within specifications, repair as necessary.

2. Perform the Line Pressure Check .

⇒	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 .

•	Spacer plate and gasket damaged or not assembled correctly

•	Refer to 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 .

•	Oil pump assembly damaged or missing components

•	Refer to Transmission Fluid Pump Disassemble .

3. 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 .

•	Forward servo assembly damaged or not assembled correctly

•	Refer to Forward Servo Removal .

•	Oil pump assembly damaged or missing components

•	Refer to Transmission Fluid Pump Disassemble .

•	Spacer plate and gaskets damaged or not assembled correctly

•	Refer to Control Valve Body and Spacer Plate Assemble .

•	Driven sprocket support seals damaged or missing

•	Refer to 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 .

•	Forward band burned, damaged, or not assembled correctly

•	Refer to 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 .

4. 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 .

•	Oil pump assembly damaged or missing components

•	Refer to Transmission Fluid Pump Disassemble .

•	Spacer plate and gaskets damaged or not assembled correctly

•	Refer to Control Valve Body and Spacer Plate Assemble .

•	Driven sprocket support seals damaged or missing

•	Refer to 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 .

•	Third sprag clutch assembly damaged or not assembled correctly

•	Refer to Input and 3rd Clutch Pawl Disassemble .

5. 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 .

•	Spacer plate and gaskets damaged or not assembled correctly

•	Refer to 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 .

•	Fourth clutch piston seal rolled or damaged

•	Fourth clutch piston damaged, not assembled correctly, or seized

•	Refer to Driven Sprocket Support Assembly Removal .

•	Fourth clutch fiber and steel plates not assembled correctly, burned, or damaged

•	Refer to 4th Clutch Components Removal .

•	Fourth clutch spring assembly damaged or not assembled correctly

•	Refer to Driven Sprocket Support Assembly Removal .

6. Replace the automatic transmission fluid and filter. Add new automatic transmission fluid. Refer to Transmission Fluid 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 TCM will update the transmission adapt cell values as the vehicle is driven

7. Perform the Transmission Adapts function.

Perform the Diagnostic Repair Verification after completing the repair.