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 1.
If the transmission control module (TCM) detects a counter value of 2 during 1 trip, then DTC P1811 sets. DTC P1811 is a type C DTC.
This diagnostic procedure supports the following DTC:
DTC P1811 Maximum Adapt and Long Shift
• | The shift is adaptable. |
• | The 1-2, 2-3, or 3-4 shift adapt cell has reached its limit. |
The 1-2, 2-3, or 3-4 shift is longer than 0.65 second, twice in 1 trip.
• | The TCM does not request the engine control module (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. |
• | 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. |
• | Ask the customer about possible overloading, exceeding the trailer towing limit, or towing in OVERDRIVE. |
• | Ensure the current TCM calibration is correct for the final drive ratio. |
The numbers below refer to the step numbers on the diagnostic table.
This step inspects components that may cause low line pressure.
This step inspects or repairs components that may cause a maximum adapt and long 1-2 upshift.
This step inspects or repairs components that may cause a maximum adapt and long 2-3 upshift.
This step inspects or repairs components that may cause a maximum adapt and long 3-4 upshift.
Step | Action | Values | Yes | No | ||||||||||||||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||||||||||||||||||||||||||||||||
2 | Did you perform the Transmission Fluid Checking Procedure? | -- | Go to Step 3 | Go to Transmission Fluid Check | ||||||||||||||||||||||||||||||||||||||
3 |
Important: Before clearing the DTCs, use the scan tool in order to record the Failure Records for reference. Using the Clear Info function will erase the stored Failure Records from the TCM. Is DTC P0120, P0220, P0218, P0711, P0712, P0722 or P0723 also set? | -- | Go to Step 4 | Go to Step 5 | ||||||||||||||||||||||||||||||||||||||
4 | Diagnose the above DTCs first. Did you complete the diagnosis and repair? | -- | Go to Step 14 | -- | ||||||||||||||||||||||||||||||||||||||
5 |
Do all the shift times exceed the specified value? | 0.65 second | Go to Step 6 | Go to Step 8 | ||||||||||||||||||||||||||||||||||||||
6 | Perform the Line Pressure Check. Refer to Line Pressure Check . Is the line pressure within specifications? | -- | Go to Diagnostic Aids | Go to Step 7 | ||||||||||||||||||||||||||||||||||||||
Inspect the transmission for the following conditions:
Refer to Incorrect Line Pressure . Did you complete the repair? | -- | Go to Step 14 | -- | |||||||||||||||||||||||||||||||||||||||
8 | Did the 1-2 shift time exceed the specified value? | 0.65 second | Go to Step 9 | Go to Step 10 | ||||||||||||||||||||||||||||||||||||||
Inspect the transmission for the following conditions:
Did you complete the repair? | -- | Go to Step 14 | -- | |||||||||||||||||||||||||||||||||||||||
10 | Did the 2-3 shift time exceed the specified value? | 0.65 second | Go to Step 11 | Go to Step 12 | ||||||||||||||||||||||||||||||||||||||
Inspect the transmission for the following conditions:
Did you complete the repair? | -- | Go to Step 14 | -- | |||||||||||||||||||||||||||||||||||||||
12 | Did the 3-4 shift time exceed the specified value? | 0.65 second | Go to Step 13 | Go to Diagnostic Aids | ||||||||||||||||||||||||||||||||||||||
Inspect the transmission for the following conditions:
Did you complete the repair? | -- | Go to Step 14 | -- | |||||||||||||||||||||||||||||||||||||||
14 |
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. Did you complete the above procedure? | -- | Go to Step 15 | -- | ||||||||||||||||||||||||||||||||||||||
15 | Perform the following procedure in order to verify the repair:
Is each shift time less than 0.65 second? | -- | Go to Step 16 | Go to Step 2 | ||||||||||||||||||||||||||||||||||||||
16 | With a scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |