AutoCodes – Chevrolet – P0121 2018 Chevrolet Silverado

P0121 2018 Chevrolet Silverado Code - Throttle Position Sensor 1 Performance

Quick Answer

The Throttle Body Assembly contains a contact-less inductive throttle position sensing element that is managed by a customized integrated circuit. Common causes include Faulty Throttle Body Assembly, Throttle Body Assembly harness is open or shorted, Throttle Body Assembly circuit poor electrical connection. 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 2018 Chevrolet Silverado indicates Throttle Position Sensor 1 Performance.
Common causes: Common causes include Faulty Throttle Body Assembly, Throttle Body Assembly harness is open or shorted, Throttle Body Assembly circuit poor electrical connection.
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 1,261

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 May 20, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code P0121 2018 Chevrolet Silverado Description

The Throttle Body Assembly contains a contact-less inductive throttle position sensing element that is managed by a customized integrated circuit. The throttle position sensor is mounted within the throttle body assembly and is not serviceable. The Engine Control Module (ECM) supplies the throttle body with a 5 V reference circuit, a low reference circuit. The asynchronous signal means communication is only going from the throttle body to the ECM. The throttle body cannot receive data from the ECM over the signal/serial data circuit. The throttle position sensor provides a signal voltage that changes relative to throttle blade angle. The throttle position sensor information is transmitted between the throttle body and the ECM on the signal/serial data circuit. The ECM decodes the serial data signal and is used as voltages for throttle position sensor 1 and 2. The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the throttle position sensor 1 voltage is stuck in range for greater than 1 s.

OBDII Code P0121 2018 Chevrolet Silverado - Throttle Position Sensor 1 Performance - AutoCodes.com — P0121 2018 Chevrolet Silverado Code - Throttle Position Sensor 1 Performance

What does this mean?

What are the Possible Causes of the DTC P0121 2018 Chevrolet Silverado?

Faulty Throttle Body Assembly
Throttle Body Assembly harness is open or shorted
Throttle Body Assembly circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0121 2018 Chevrolet Silverado?

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

User Submitted Video

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0121 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado Code

1. What are the common symptoms of OBDII code P0121 in a 2018 Chevrolet Silverado?

Symptoms may include reduced engine power, hesitation or stalling when accelerating, and illuminated check engine light.

2. What does the OBDII code P0121 indicate in a 2018 Chevrolet Silverado?

Code P0121 signifies a performance issue with Throttle Position Sensor 1 (TPS) on the Chevrolet Silverado.

3. What are the possible causes of OBDII code P0121 in a 2018 Chevrolet Silverado?

Common causes include a faulty TPS, wiring issues, poor electrical connections, or a malfunctioning throttle body.

4. How can I diagnose the Throttle Position Sensor in a 2018 Chevrolet Silverado with code P0121?

You can use a multimeter to test the TPS for proper voltage output, inspect the wiring for any damage, and check for loose connections.

5. Can a dirty throttle body cause OBDII code P0121 in a 2018 Chevrolet Silverado?

Yes, a dirty throttle body can disrupt the TPS readings and lead to code P0121. Cleaning the throttle body may help resolve the issue.

6. Is it safe to continue driving a 2018 Chevrolet Silverado with OBDII code P0121?

It is not recommended to drive with code P0121 as it can affect the vehicle's performance and fuel efficiency. Address the issue promptly.

7. How can I reset the OBDII code P0121 in a 2018 Chevrolet Silverado?

You can reset the code using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes. However, the underlying issue must be fixed.

8. Can I repair OBDII code P0121 in a 2018 Chevrolet Silverado myself?

Depending on your mechanical skills, you may be able to replace the TPS or fix wiring issues yourself. If unsure, it's best to consult a professional mechanic.

9. Will OBDII code P0121 cause permanent damage to my 2018 Chevrolet Silverado if left unresolved?

Continuing to drive with code P0121 may lead to further engine damage and worsen performance over time. It's important to address the issue promptly.

10. How much does it typically cost to repair OBDII code P0121 in a 2018 Chevrolet Silverado?

The cost of repair can vary depending on the exact cause of the issue. Replacing the TPS or fixing wiring problems may range from $100 to $300 at a repair shop.