Duty Cycle, Frequency and Current Flow
A "duty cycle" may be defined as the percentage of time current is flowing through a solenoid coil during each cycle. The number of cycles that occur within a specified amount of time, usually measured in seconds, is called "frequency". Typically, the operation of an electronically controlled pulse width modulated solenoid is explained in terms of duty cycle and frequency.
The TCM controls the line pressure control solenoid valve on a positive duty cycle at a fixed frequency of 292.5 Hz (cycles-per-second). A higher duty cycle provides a greater current flow through the solenoid. The high (positive) side of the line pressure control solenoid valve electrical circuit at the TCM controls the line pressure control solenoid valve operation. The TCM provides a ground path for the circuit, monitors average current and continuously varies the line pressure control solenoid valve duty cycle to maintain the correct average current flowing through the line pressure control solenoid valve.
| Duty Cycle | Current | Line Pressure |
|---|---|---|
| Minimum | 0.1 amps | Maximum |
| Maximum | 1.1 amps | Minimum |
Line pressure control solenoid valve resistance should measure between 5.0 and 5.6 ohms when measured at 20°C (68°F).
The duty cycle and current flow to the line pressure control solenoid valve are mainly affected by throttle position (engine torque) and they are inversely proportional to throttle angle (engine torque). In other words, as the throttle angle (engine torque) increases, the duty cycle is decreased by the TCM which decreases current flow to the line pressure control solenoid valve. Current flow to the line pressure control solenoid valve creates a magnetic field that moves the solenoid plunger against spring force.
A "duty cycle" may be defined as the percentage of time current is flowing through a solenoid coil during each cycle. The number of cycles that occur within a specified amount of time, usually measured in seconds, is called "frequency". Typically, the operation of an electronically controlled pulse width modulated solenoid is explained in terms of duty cycle and frequency.
The TCM controls the shift pressure control solenoid valve on a positive duty cycle at a fixed frequency of 292.5 Hz (cycles-per-second). A higher duty cycle provides a greater current flow through the solenoid. The high (positive) side of the shift pressure control solenoid valve electrical circuit at the TCM controls the shift pressure control solenoid valve operation. The TCM provides a ground path for the circuit, monitors average current and continuously varies the shift pressure control solenoid valve duty cycle to maintain the correct average current flowing through the shift pressure control solenoid valve.
| Duty Cycle | Current | Line Pressure |
|---|---|---|
| Minimum | 0.1 amps | Maximum |
| Maximum | 1.1 amps | Minimum |
Shift pressure control solenoid valve resistance should measure between 5.0 and 5.6 ohms when measured at 20°C (68°F).
The duty cycle and current flow to the shift pressure control solenoid valve are mainly affected by throttle position (engine torque) and they are inversely proportional to throttle angle (engine torque). In other words, as the throttle angle (engine torque) increases, the duty cycle is decreased by the TCM which decreases current flow to the shift pressure control solenoid valve. Current flow to the shift pressure control solenoid valve creates a magnetic field that moves the solenoid plunger against spring force.