The transmission control module (TCM) modifies the transmission line pressure
through the pressure control (PC) solenoid valve, in order to control shift execution
time and shift consistency. The TCM monitors various inputs, and modifies the shift
execution and timing by applying a calculated duty cycle to the PC solenoid valve.
The TCM alters the shifting based on driving habits, transmission load, and internal
transmission condition.
When the TCM detects long shifts that cannot be shortened by shift adapts during
the same ignition cycle, then DTC P1811 sets. DTC P1811 is a type C DTC.
The shift time is greater than 0.65 second twice during the same trip.
Ask the customer about overloading the vehicle, exceeding the trailer towing
limit, or towing in Overdrive.
The numbers below refer to the step numbers on the diagnostic table.
Step
| Action
| Value(s)
| Yes
| No
|
1
| Did you perform the Diagnostic System Check - Vehicle?
| --
| Go to
Step 2
| Go to
Diagnostic System Check - Vehicle
|
2
| Did you perform the Transmission Fluid Checking Procedure?
| --
| Go to
Step 3
| Go to
Transmission Fluid Check
|
3
|
- Install a scan tool.
- Turn ON the ignition, with the engine OFF.
Important: Before clearing the DTC, use the scan tool
in order to record the Failure Records. Using the Clear Info function erases the Failure
Records from the TCM.
- Record the DTC Failure Records.
- Clear the DTC.
- Use the scan tool snapshot mode in order to record the shift times.
- Drive the vehicle in D4 in order to obtain 1-2, 2-3, and
3-4 shift times.
- Record the shift times.
Did all the shift times exceed the specified value?
| 0.65 second
| Go to
Step 4
| Go to
Step 6
|
4
| Did you perform the Line Pressure Check Procedure?
| --
| Go to
Step 5
| Go to
Line Pressure Check
|
5
|
- Inspect the transmission for the following conditions:
• | Low fluid level caused by external leaks |
• | Internal fluid passage leaks |
• | Casting porosity or damage |
• | Out-of-position fluid filter |
• | Damaged gasket or spacer plate |
• | Out-of-position gasket or spacer plate |
• | Contaminated PC solenoid valve |
• | Damaged PC solenoid valve |
• | Stuck PC solenoid valve |
• | Stuck pressure regulator valve train |
• | Leaking pressure regulator valve train |
• | Stuck torque signal valve train |
• | Leaking torque signal valve train |
• | Inadequate oil pump suction |
- Repair any of the above conditions as necessary.
Did you complete the repair?
| --
| Go to
Step 12
| --
|
6
| Did the 1-2 shift time exceed the specified value?
| 0.65 second
| Go to
Step 9
| Go to
Step 7
|
7
| Did the 2-3 shift time exceed the specified value?
| 0.65 second
| Go to
Step 10
| Go to
Step 8
|
8
| Did the 3-4 shift time exceed the specified value?
| 0.65 second
| Go to
Step 11
| --
|
9
|
- Inspect the 1-2 shift circuit for the following conditions:
• | Leaking 1-2 accumulator piston seals |
• | Rolled 1-2 accumulator piston seals |
• | Cut 1-2 accumulator piston seals |
• | 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 |
• | Internal fluid passage leaks |
• | Casting porosity or damage |
• | Damaged gasket or spacer plate |
• | Out-of-position gasket or spacer plate |
• | Slipping forward clutch |
• | Damaged sprag clutch, not holding |
• | 2nd roller clutch damaged, not holding |
- Repair the 1-2 shift circuit as necessary.
Did you complete the repair?
| --
| Go to
Step 12
| --
|
10
|
- Inspect the 2-3 shift circuit for the following conditions:
• | Leaking 2-3 accumulator piston seals |
• | Rolled 2-3 accumulator piston seals |
• | Cut 2-3 accumulator piston seals |
• | 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 |
• | Leaking driven sprocket support seals |
• | Damaged driven sprocket support seals |
• | Damaged driven sprocket support |
• | Internal fluid passage leaks |
• | Casting porosity or damage |
• | Damaged gasket or spacer plate |
• | Out-of-position gasket or spacer plate |
- Repair the 2-3 shift circuit as necessary.
Did you complete the repair?
| --
| Go to
Step 12
| --
|
11
|
- Inspect the 3-4 shift circuit for the following conditions:
• | Leaking 3-4 accumulator piston seals |
• | Rolled 3-4 accumulator piston seals |
• | Cut 3-4 accumulator piston seals |
• | 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 |
• | Burned intermediate/4th band |
• | Out-of-position intermediate/4th band |
• | Damaged intermediate/4th band |
• | Slipping intermediate/4th band |
• | Internal fluid passage leaks |
• | Casting porosity or damage |
• | Damaged gasket or spacer plate |
• | Out-of-position gasket or spacer plate |
- Repair the 3-4 shift circuit as necessary.
Did you complete the repair?
| --
| Go to
Step 12
| --
|
12
|
- Change the AT fluid and filter. Refer to
Automatic Transmission Fluid Filter and Seal Replacement
.
- Inspect the transmission fluid for correct level.
- Add new fluid as necessary.
Did you complete the above procedures?
| --
| Go to
Step 13
| --
|
13
| Perform the following procedure in order to verify the repair:
- Select DTC.
- Select Clear Info.
- Operate the vehicle under the following conditions:
• | Drive the vehicle in D4 in order to obtain 1-2, 2-3, and
3-4 shifts. |
• | Shift times must be less than 0.65 second. |
- Select Specific DTC.
- Enter DTC P1811.
Has the test run and passed?
| --
| Go to
Step 14
| Go to
Step 2
|
14
| With the scan tool, observe the stored information, capture info and DTC info.
Does the scan tool display any DTCs that you have not diagnosed?
| --
| Go to
Diagnostic Trouble Code (DTC) List - Vehicle
| System OK
|