Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

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 one.

The 1-2, 2-3, or 3-4 shift is longer than 0.65 second, twice in one 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 that the transmission fluid level is at the proper level by performing the Transmission Fluid Check . Ensure that 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 damage or misassembled. Refer to Control Valve Body and Spacer Plate Assemble in Transmission Unit Repair Manual.

•	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 in Transmission Unit Repair Manual.

•	Oil pump assembly damaged or missing components. Refer to Transmission Fluid Pump Disassemble in Transmission Unit Repair Manual.

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 above 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 in Transmission Unit Repair Manual.

•	Forward servo assembly damaged or misassembled. Refer to Forward Servo Removal in Transmission Unit Repair Manual.

•	Oil pump assembly damaged or missing components. Refer to Transmission Fluid Pump Disassemble in Transmission Unit Repair Manual.

•	Spacer plate and gaskets damaged or misassembled. Refer to Control Valve Body and Spacer Plate Assemble in Transmission Unit Repair Manual.

•	Driven sprocket support seals damaged or missing. Refer to Driven Sprocket Support Assembly Removal in Transmission Unit Repair Manual.

•	Second clutch piston and seal assembly binding or damaged

•	Second clutch fiber and steel plates misassembled, burned, or damaged

•	Second clutch spring assembly damaged or misassembled. Refer to 2nd Clutch Disassemble in Transmission Unit Repair Manual.

•	Forward band burned, damaged, or misassembled. Refer to 1-2 Support Drum and Forward Band Removal in Transmission Unit Repair Manual.

•	1-2 support roller clutch assembly damaged or misassembled. Refer to 1-2 Support Roller Clutch Disassemble in Transmission Unit Repair Manual.

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 above 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 in Transmission Unit Repair Manual.

•	Oil pump assembly damaged or missing components. Refer to Transmission Fluid Pump Disassemble in Transmission Unit Repair Manual.

•	Spacer plate and gaskets damaged or misassembled. Refer to Control Valve Body and Spacer Plate Assemble in Transmission Unit Repair Manual.

•	Driven sprocket support seals damaged or missing. Refer to Driven Sprocket Support Assembly Removal in Transmission Unit Repair Manual.

•	Third clutch piston seal rolled or damaged

•	Third clutch piston damaged or misassembled

•	Third clutch fiber and steel plates misassembled, burned, or damaged

•	Third clutch spring assembly damaged or misassembled. Refer to Input and 3rd Clutch Disassemble in Transmission Unit Repair Manual.

•	Third sprag clutch assembly damaged or misassembled. Refer to Input and 3rd Clutch Pawl Disassemble in Transmission Unit Repair Manual.

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 above 0.65 second, inspect and repair the following components:

•	Oil pump assembly damaged or missing components. Refer to Transmission Fluid Pump Disassemble in Transmission Unit Repair Manual.

•	Spacer plate and gaskets damaged or misassembled. Refer to Control Valve Body and Spacer Plate Assemble in Transmission Unit Repair Manual.

•	3-4 accumulator piston seals rolled or damaged

•	3-4 accumulator piston and pin missing, binding, or damaged. Refer to Case Assembly Inspection in Transmission Unit Repair Manual.

•	Fourth clutch piston seal rolled or damaged

•	Fourth clutch piston damaged, misassembled, or seized. Refer to Driven Sprocket Support Assembly Removal in Transmission Unit Repair Manual.

•	Fourth clutch fiber and steel plates misassembled, burned, or damaged. Refer to 4th Clutch Components Removal in Transmission Unit Repair Manual.

•	Fourth clutch spring assembly damaged or misassembled. Refer to Driven Sprocket Support Assembly Removal in Transmission Unit Repair Manual.

6. Change the AT fluid and filter. Add new AT fluid, refer to Transmission Fluid Check .

⇒	If the fluid is not at the proper level, add 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.

Transmission Fluid Check

Line Pressure Check

Incorrect Line Pressure

Perform the Diagnostic Repair Verification after completing the repair.