Throttle Position (TP) Sensor

DESCRIPTION
Throttle Position (TP) Sensor is a potentiometer which is mounted to the throttle body. The TP sensor detects the position of the throttle plate and sends this information to the powertrain control module (PCM) in the form of a voltage signal. All 4.6L engines use a standard TP sensor which is known as TP-A. This TP sensor performs the same function as a standard throttle position sensor. TP-A data is sent to the PCM, then broadcast by the PCM to the ABS/TC module. Vehicles equipped with traction control have a secondary TP sensor known as TP-B. TP-B data is sent to the PCM, then relayed to the series throttle controller. When wheel slip becomes imminent, the ABS/TC module tells the PCM to lower engine torque output by broadcasting a "Desired Axle Torque Limit Value" message to the PCM.

The PCM calculates the amount of throttle closure necessary to reduce engine torque to the desired limit and sends that information to the series throttle controller. The series throttle controller then closes the series throttle to lower engine torque. The PCM uses the monitored voltage level of the TP-A sensor for control of EPC pressure, torque converter clutch operation and shift scheduling.

If a malfunction occurs in the TP circuit, the PCM will identify that an out-of-specification condition exists in the TP circuit. The PCM will then operate the AX4N in a high capacity mode to prevent transaxle damage.

SYMPTOMS
TP-A Only:
Harsh engagements, firm shift feel, abnormal shift schedule, TCC does not engage, torque converter clutch cycling.
TP-B Only:
TCC disengaged, PID Parameter TRAC-ULFLG= 1.

DTC's
TP-A Only:
P0122, P0123, P 1120
TP-B Only:
P0222, P0223, P1220