This calibration procedure must be performed under the following conditions:
- Replacement of one or all ECPC valves
- The initial assembly of a new machine
- Changing ECPC valves between positions
- Replacement of the Electronic Control Unit (ECU)
- An ECU that is exchanged between machines
There are variations in shift solenoids from the factory. Because of these variations, the position of first gear and the position of second gear may overlap. The ECU automatically determines the detent for first gear by looking for a stable duty cycle. The stable duty cycle is a lower duty cycle than the current duty cycle used for first gear. When a stable duty cycle is read the ECU uses the stable value as the new first gear position. The ECU adjusts the position for second gear accordingly.
This automatic process will not detect the detent for first gear correctly if new solenoids are installed or if the ECU has been replaced on the machine. Therefore, a manual procedure to reset the calibration back to the default is required.
For a well service work over rig application, the park brake must be applied in order for calibration to execute. For a pump application, the drive shaft must be disconnected and the Cat 284-0837 Holding Fixture (TRANSMISSION AUTOCALIBRATION) must be bolted onto the transmission. The Holding Fixture must be used in order to complete the auto-calibration sequence. The 288-7353 Special Bolt (SHEAR) can be replaced.
Use the following procedure in order to calibrate the ECU to the shift solenoid that is installed on the machine.
- Start the procedure with Caterpillar Electronic Technician (Cat ET). The machine must be in NEUTRAL. The engine must be running and the transmission oil must be warm.