Pressure Regulator and Shift Solenoid Valves

Pressure Regulator and Shift Solenoid Valves Description

The Pressure regulator controls the oil pressure within the transmission. This determines the time each shift takes to be completed and consequently the quality of the shift. If the shift is long, the gear change will be very smooth but this can accelerate wear on the transmission clutches. The solenoid valves control the selected gear as well as the status of the Torque Converter.

There are two diagnostic checks for each solenoid valve.
A fault is detected if:
1. Circuit Continuity - The solenoid valve is energized, and the command signal and the check signal do not match.
2. Functional Check
1st check; the solenoid valve is not energized and the ignition is ON.
2nd check; the solenoid valve is not energized and the battery voltage is greater than 10.5 volts but less than 15 volts.

For the diagnostic tables, please refer to the individual codes:
Table 1 (i.e. P0743, P0750, P0753, P0755 or P0758) P0743
Table 2 (i.e. P0745 or P0748) P0745

If the above tables do not include details of the following enabling conditions: - IAT ECT, vehicle speed range, and time after engine start-up then the state of these parameters has no influence upon the execution of the monitor.