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 seconds 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 seconds, twice in one trip.

DTC P1811 is a Type C DTC.

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Transmission Adaptive Functions

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

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 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 Oil Pump Cleaning and Inspection .

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 seconds.

⇒	If the shift time is above 0.65 seconds, inspect and repair the following components:

•	Leaking 1-2 accumulator piston seals

•	Rolled 1-2 accumulator piston seals

•	Cut 1-2 accumulator piston seals

•	Refer to Channel Plate Assembly Disassemble .

•	Leaking 2nd clutch piston seals

•	Rolled 2nd clutch piston seals

•	Cut 2nd clutch piston seals

•	Burned 2nd clutch plates

•	Damaged 2nd clutch plates

•	Broken 2nd clutch springs

•	Out-of-position 2nd clutch springs

•	Damaged 2nd clutch piston

•	Cracked or damaged driven sprocket support

•	Leaking driven sprocket support seals

•	Damaged driven sprocket support seals

•	Refer to Driven Sprocket Support Assembly Disassemble .

•	Internal fluid passage leaks

•	Casting porosity or damage

•	Refer to Case Inspection .

•	Damaged gasket or spacer plate

•	Out-of-position gasket or spacer plate

•	Refer to Control Valve Body Disassemble .

•	Slipping forward clutch

•	Damaged sprag clutch, not holding

•	Refer to Direct/Coast Clutch, Reaction Carrier Disassemble .

•	2nd roller clutch damaged, not holding

•	Refer to Reverse Input and Second 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 seconds.

⇒	If the 2-3 shift time is above 0.65 seconds, inspect and repair the following components:

•	Leaking 2-3 accumulator piston seals

•	Rolled 2-3 accumulator piston seals

•	Cut 2-3 accumulator piston seals

•	Refer to Channel Plate Assembly Disassemble .

•	Leaking direct clutch piston seals

•	Rolled direct clutch piston seals

•	Cut direct clutch piston seals

•	Burned direct clutch plates

•	Damaged direct clutch plates

•	Broken direct clutch springs

•	Out-of-position direct clutch springs

•	Damaged direct clutch pistons

•	Damaged, or not holding, sprag clutch

•	Refer to Direct/Coast Clutch, Reaction Carrier Disassemble .

•	Leaking driven sprocket support seals

•	Damaged driven sprocket support seals

•	Damaged driven sprocket support

•	Refer to Driven Sprocket Support Assembly Disassemble .

•	Internal fluid passage leaks

•	Casting porosity or damage

•	Refer to Case Inspection .

•	Damaged gasket or spacer plate

•	Out-of-position gasket or spacer plate

•	Refer to Control Valve Body 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 seconds.

⇒	If the 3-4 shift time is above 0.65 seconds, inspect and repair the following components:

•	Leaking 3-4 accumulator piston seals

•	Rolled 3-4 accumulator piston seals

•	Cut 3-4 accumulator piston seals

•	Refer to Channel Plate Assembly Disassemble .

•	Leaking intermediate/4th servo piston seals

•	Rolled intermediate/4th servo piston seals

•	Cut intermediate/4th servo piston seals

•	Damaged intermediate/4th servo pin

•	Seized intermediate/4th servo pin

•	Damaged intermediate/4th servo piston

•	Cracked intermediate/4th servo cover

•	Leaking intermediate/4th servo cover

•	Refer to Intermediate/Fourth Servo Disassemble .

•	Burned intermediate/4th band

•	Out-of-position intermediate/4th band

•	Damaged intermediate/4th band

•	Slipping intermediate/4th band

•	Refer to Intermediate Fourth Band Removal .

•	Internal fluid passage leaks

•	Casting porosity or damage

•	Refer to Case Inspection .

•	Damaged gasket or spacer plate

•	Out-of-position gasket or spacer plate

•	Refer to Control Valve Body Disassemble .

•	Slipping direct clutch

•	Refer to Direct/Coast Clutch, Reaction Carrier Disassemble .

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.

Perform the Diagnostic Repair Verification after completing the repair.