P1811
DTC P1811
Circuit Description
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.
If the transmission control module (TCM) detects a counter value of 2 during one trip, 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 1-2, the 2-3 or the 3-4 shift adapt cell has reached its limit.
Conditions for Setting the DTC
The 1-2, 2-3 or 3-4 shift is longer than 0.65 seconds, twice in one trip.
Action Taken When the DTC Sets
^ The TCM does not request the ECM to 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 possible overloading, exceeding the trailer towing limit, or towing in overdrive.
^ Ensure that the current TCM calibration is correct for the final drive ratio.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
7. This step inspects components that may cause low line pressure.
9. This step inspects or repairs components that may cause a maximum adapt and long 1-2 upshift.
11. This step inspects or repairs components that may cause a maximum adapt and long 2-3 upshift.
13. This step inspects or repairs components that may cause a maximum adapt and long 3-4 upshift.
Step 1 - Step 8:
Step 9 - Step 12:
