AutoCodes – Chevrolet – P1121 Chevrolet

P1121 Chevrolet Code - Throttle Position Sensor Circuit Intermittent High Voltage

Quick Answer

The Throttle Position (TP) sensor is a potentiometer. Common causes include Faulty Throttle Position Sensor, Throttle Position Sensor harness is open or shorted, Throttle Position Sensor 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: P1121 Chevrolet indicates Throttle Position Sensor Circuit Intermittent High Voltage.
Common causes: Common causes include Faulty Throttle Position Sensor, Throttle Position Sensor harness is open or shorted, Throttle Position Sensor 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 13,705

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 Apr 25, 2019

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1121 Chevrolet Description

The Throttle Position (TP) sensor is a potentiometer. The TP sensor provides a voltage signal that changes relative to throttle blade angle. This signal voltage is one of the most important inputs used by the Powertrain Control Module (PCM). The TP sensor has a 5.0 volt reference, a ground and a signal circuit.
TP sensor Signal voltage should be about 0.6 volt at idle. The TP sensor voltage should increase to above 4.0 volts at wide open throttle (WOT).

OBDII Code P1121 Chevrolet - Throttle Position Sensor Circuit Intermittent High Voltage - AutoCodes.com — P1121 Chevrolet Code - Throttle Position Sensor Circuit Intermittent High Voltage

What does this mean?

What are the Possible Causes of the DTC P1121 Chevrolet?

Faulty Throttle Position Sensor
Throttle Position Sensor harness is open or shorted
Throttle Position Sensor circuit poor electrical connection
Throttle Position Sensor not properly adjusted

How to Fix the DTC P1121 Chevrolet?

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 is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1121 Chevrolet 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.