P1811
DTC P1811
Circuit Description
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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1811 Maximum Adapt and Long Shift
Conditions for Running the DTC
^ The shift is adaptable.
^ The shift adapt is at the limit.
Conditions for Setting the DTC
The shift time is greater than 0.65 second twice during the same trip.
Action Taken When the DTC Sets
^ The TCM does not illuminate the malfunction indicator lamp (MIL).
^ The TCM commands maximum line pressure.
^ The TCM freezes transmission adaptive functions.
^ The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
^ The TCM stores DTC P1811 in TCM history.
Conditions for Clearing the DTC
^ A scan tool can clear the DTC.
^ The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring.
^ The TCM cancels the DTC default actions when the fault no longer exists and the DTC passes.
Diagnostic Aids
Ask the customer about overloading the vehicle, exceeding the trailer towing limit, or towing in Overdrive.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step tests for low fluid level, which can cause long shifts.
4. This step tests for low line pressure, which can cause long shifts.
Step 1 - Step 8:
Step 9:
Step 10:
Step 11 - Step 13:
