Throttle Position Sensor

The 3-wire Throttle Position (TP) sensor is mounted on the throttle body and is connected to the throttle blade. See Fig 1 and Fig 2 . The (TP) sensor is a 3-wire variable resistor that provides the Powertrain Control Module (PCM) with an input signal (voltage) that represents the throttle blade position of the throttle body. The sensor is connected to the throttle blade shaft. As the position of the throttle blade changes, the resistance (output voltage) of the (TP) sensor changes. The PCM supplies approximately 5 volts to the (TP) sensor. The (TP) sensor output voltage (input signal to the PCM) represents the throttle blade position. The PCM receives an input signal voltage from the (TP) sensor. This will vary in an approximate range of from 0.26 volt at minimum throttle opening (idle), to 4.49 volts at wide open throttle. Along with inputs from other sensors, the PCM uses the (TP) sensor input to determine current engine operating conditions. In response to engine operating conditions, the PCM will adjust fuel injector pulse width and ignition timing. The PCM needs to identify the actions and position of the throttle blade at all times. This information is needed to assist in performing the following calculations:

• Ignition Timing Advance
• Fuel Injection Pulse-Width
• Idle (Learned Value Or Minimum (TP) Sensor)
• Off-Idle (0.06 Volt)
• Wide Open Throttle (WOT) Open Loop (2.608 Volts Above Learned Idle Voltage)
• Deceleration Fuel Lean Out
• Fuel Cutoff During Cranking At WOT (2.608 Volts Above Learned Idle Voltage)
• A/C WOT Cutoff (Certain Automatic Transmissions Only)

Fig 1: Identifying Throttle Position Sensor (3.9L & 5.9L)

Courtesy of CHRYSLER CORP.

Fig 2: Identifying Throttle Position Sensor (4.7L)

Courtesy of CHRYSLER CORP.