Engine-Codes - Ford - P0121 2002 FORD F150

P0121 2002 FORD F150 - Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance

Repair Importance Level: 3/3
Repair Difficulty Level: 2/3  What is this?
Table of contents

P0121 2002 FORD F150 Possible Causes

  • Binding throttle linkage
  • Faulty throttle position sensor
  • Throttle position sensor harness is open or shorted
  • Throttle position sensor circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

How is the P0121 2002 FORD F150 code repair?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

Tech Notes

The TP sensor circuit is monitored by the PCM for a non closed throttle position at idle. If key ON engine running self-test terminates upon placing the transmission range selector in gear (DRIVE or REVERSE) or when closing the throttle (idle) after opening it (in PARK or NEUTRAL) the TP closed throttle position is not attained, the test fails.

What is the cost to diagnose the P0121 2002 FORD F150 code

Labor: 1.0

The cost to diagnose the P0121 2002 FORD F150 code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.
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When is the code detected?

Malfunction is detected when an excessively low or high voltage from the sensor is sent to ECM.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P0121 2002 FORD F150 Meaning

The throttle position sensor (TPS) responds to the accelerator pedal movement. This sensor is a kind of potentiometer which transforms the throttle position into output voltage, and emits the voltage signal to the Engine Control Module (ECM). In addition, the sensor detects the opening and closing speed of the throttle valve and feeds the voltage signal to the ECM.
Idle position of the throttle valve is determined by the ECM receiving the signal from the throttle position sensor. This sensor controls engine operation such as fuel cut. On the other hand, the Wide open and closed throttle position switch, which is built into the throttle position sensor unit, is not used for engine control.

More Information

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