The 4T65-E transmission uses a line pressure control system, which has the ability to continuously adapt the system's line pressure. This compensates for normal wear of the following parts:
| • | The clutch fiber plates |
| • | The seals |
| • | The springs |
This learning feature is similar to that which is used for fuel control and idle position.
The PCM maintains the following adapt parameter for the transmission:
Upshift Adapt -- The PCM monitors the Automatic Transmission Input (Shaft) Speed Sensor (A/T ISS) and the Vehicle Speed Sensor (VSS) during commanded shifts in order to determine if a shift is occurring too fast or too slow. The PCM adjusts the signal to the transmission Pressure Control Solenoid (PCS) valve in order to maintain a set shift feel.
Transmission adapts must be reset whenever the transmission is overhauled or replaced. In order to reset transmission adapts, select the following:
- Scan tool
- Miscellaneous test
- A/T outputs
- Clear or reset all adapts
