Powertrain Control Module (PCM)
The park/neutral position (PNP) switch is mounted on the side of the manual transmission. The PNP switch sends a signal to the powertrain control module (PCM) when the manual transmission is in neutral. The PCM uses this input for idle speed control.
Brake Pedal Position (BPP) Switch
The brake pedal position (BPP) switch is located on the brake pedal. The BPP switch sends a signal to the PCM when the brake pedal is depressed.
Engine Coolant Temperature (ECT) Sensor
The engine coolant temperature sensor (ECT sensor) signal is used by the PCNI to modify ignition timing and the air-to-fuel ratio.
Intake Air Temperature (IAT) Sensor
The PCM uses the intake air temperature sensor (IAT sensor) signal to proportion the cold enrichment fuel flow and as a density corrector for air flow calculations.
Mass Air Flow (MAF) Sensor
The mass air flow sensor (MAF sensor) measures the mass of the air flowing into the engine. The PCM uses the MAF sensor signal to calculate the fuel injector pulse width.
Power Steering Pressure (PSP) Switch
A power steering pressure switch (PSP switch), located on the power steering pressure hose, is normally closed. As the power steering load increases, the PSP switch opens and signals the PCM to increase the idle speed.
Throttle Position (TP) Sensor
The throttle position sensor (TP sensor) is a rotary potentiometer in which the PCM determines four operating modes from the TP signal. These are:
Closed throttle (idle or deceleration).
Part throttle (cruise, moderate acceleration).
Wide open throttle (WOT) (maximum acceleration, de-choke on crank and A/C cutout).
Throttle angle rate.
Vehicle Speed Sensor (VSS)
The vehicle speed sensor (VSS) is located above the differential on the transmission case. The VSS rotates a cable and the instrument cluster generates a DC signal and sends the signal to the PCM.
Turbine Shaft Speed (TSS) Sensor
The turbine shaft speed (TSS) sensor is a magnetic pickup that sends a signal to the PCM that indicates turbine shaft input speed. The TSS sensor provides converter turbine shaft speed information for torque converter clutch(TCC) control strategy. The information is also used in determining static electronic pressure control (EPC) pressure setting during shifts.
Transmission Fluid Temperature (TFT) Sensor
The transmission fluid temperature sensor (TFT sensor) is a two-wire thermistor that is part of the main wiring harness. It receives a voltage signal which is reduced by the resistance of the sensor in accordance with temperature. The signal is then sent to the PCM which interprets the voltage signal to determine transmission fluid temperature.
Transmission Range (TR) Sensor
The transmission range (TR) sensor is mounted on top of the automatic transmission. The TR sensor prevents the engine from being started except when the gearshift lever is in the park (P) or neutral (N) position.
Torque Converter Clutch (TCC) Solenoid
The torque converter clutch(TCC) solenoid is located on the valve body and is switched on and off by electrical signals from the PCM.
The TCC solenoid activates the TCC valve which controls lockup. When the TCC solenoid is off, lockup is prevented. Lockup is actuated when the TCC solenoid is on.
Shift Solenoids (SS1, SS2, SS3)
The 1-2 shift solenoid is located on the main control valve body and is switched on and off by electrical signals from the PCM. The 1-2 shift solenoid activates the 1-2 shift valve which controls the automatic shifting between first and second gear. First gear is established when the 1-2 shift solenoid is switched off. The 1-2 shift solenoid is switched on when the vehicle speed increases and requires a first to second gear upshift.
Electronic Pressure Control (EPC) Solenoid
The electronic pressure control (EPC) solenoid is located on the main control valve body and is controlled by the PCM. The EPC controls line pressure used to apply and release clutches and bands in the transmission.
The 2-3 shift solenoid is located on the main control valve body and is switched on and off by electrical signals from the PCM. The 2-3 shift solenoid activates the 2-3 shift valve which controls the automatic shifting between second and third gear. Second gear is established when the 2-3 shift solenoid is switched on. The 2-3 shift solenoid is switched off when vehicle speed increases and requires a second to third gear upshift.
The 3-4 shift solenoid is located on the main control valve body and is switched on and off by electrical signals from the PCM. The 3-4 shift solenoid activates the 3-4 shift valve which controls the automatic shifting between third and fourth gear. Third gear is established when the 3-4 solenoid is switched off. The 3-4 shift solenoid is switched on when vehicle speed increases and requires a third to fourth gear upshift.
