AutoCodes – Ford – P0121 1999 Ford F150

P0121 1999 Ford F150 Code - Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance

Quick Answer

The throttle position sensor (TPS) responds to the accelerator pedal movement. Common causes include Binding throttle linkage, Faulty throttle position sensor, Throttle position sensor harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0121 1999 Ford F150 indicates Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance.
Common causes: Common causes include Binding throttle linkage, Faulty throttle position sensor, Throttle position sensor harness is open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 3,896

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0121 1999 Ford F150 Description

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.

OBDII Code P0121 1999 Ford F150 - Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance - AutoCodes.com — P0121 1999 Ford F150 Code - Throttle/Pedal Position Sensor/Switch 'A' Circuit Range/Performance

What does this mean?

What are the Possible Causes of the DTC P0121 1999 Ford F150?

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 to Fix the DTC P0121 1999 Ford F150?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code 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 Code?

Labor: 1.0

To diagnose the P0121 1999 Ford F150 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0121 1999 Ford F150 Code

1. What are the common symptoms of OBDII code P0121 in a 1999 Ford F150?

- Common symptoms include issues with acceleration, rough idling, stalling, and poor fuel efficiency.

2. What can cause the OBDII code P0121 in a 1999 Ford F150?

- The code P0121 is typically triggered by a faulty throttle/pedal position sensor or switch, wiring issues, or a malfunction in the electronic throttle control system.

3. How can I diagnose the cause of OBDII code P0121 in my 1999 Ford F150?

- A thorough diagnostic process involving checking the throttle position sensor, inspecting wiring for damage, and testing the electronic throttle control system is recommended.

4. Can I continue driving my 1999 Ford F150 with OBDII code P0121?

- It is not recommended to drive your vehicle with code P0121 as it can lead to performance issues and potential safety hazards. It's best to address the problem promptly.

5. How can I repair OBDII code P0121 in my 1999 Ford F150?

- Repair options may include replacing the throttle position sensor, repairing damaged wiring, or addressing issues with the electronic throttle control system.

6. Are there any DIY tips for fixing OBDII code P0121 in a 1999 Ford F150?

- While some basic troubleshooting like checking for loose connections or damaged wires can be done DIY, it is advisable to seek professional help for a thorough diagnosis and repair.

7. Will resetting the OBDII code P0121 in my 1999 Ford F150 make it go away?

- Resetting the code may temporarily clear the warning light, but if the underlying issue is not addressed, the code is likely to reappear once the system detects the problem again.

8. How much does it cost to fix OBDII code P0121 in a 1999 Ford F150?

- The cost of fixing code P0121 can vary depending on the exact cause of the issue, parts needed for replacement, and labor costs. It's best to get a professional estimate.

9. Can a bad throttle position sensor cause other problems besides triggering code P0121 in a 1999 Ford F150?

- Yes, a faulty throttle position sensor can lead to various performance issues like erratic shifting, decreased fuel efficiency, and overall drivability problems.

10. Is it safe to drive my 1999 Ford F150 to a repair shop with code P0121 triggered?

- It is recommended to avoid driving your vehicle with code P0121 triggered to prevent potential safety hazards and further damage to the engine or transmission.