AutoCodes – Pontiac – P1121 Pontiac

P1121 Pontiac 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 Pontiac 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 4,007

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
FAQs
Comments
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Code P1121 Pontiac 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 Pontiac - Throttle Position Sensor Circuit Intermittent High Voltage - AutoCodes.com — P1121 Pontiac Code - Throttle Position Sensor Circuit Intermittent High Voltage

What does this mean?

What are the Possible Causes of the DTC P1121 Pontiac?

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 Pontiac?

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 Pontiac 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 P1121 Pontiac Code

What does the OBDII code P1121 mean for a Pontiac?

Code P1121 indicates an intermittent high voltage issue in the throttle position sensor (TPS) circuit, which can disrupt proper engine performance.

What are the common symptoms of P1121 in a Pontiac?

Symptoms include poor acceleration, stalling, rough idling, reduced fuel efficiency, and possible activation of the check engine light.

What causes the P1121 code to appear in a Pontiac?

Common causes include a faulty throttle position sensor, damaged wiring or connectors, or issues with the engine control module (ECM).

Can a dirty throttle body cause a P1121 code?

Yes, carbon buildup on the throttle body can interfere with TPS readings and may contribute to this code.

How can I diagnose the P1121 code on my Pontiac?

Use an OBDII scanner to confirm the code, inspect the throttle position sensor and wiring for damage, and check for voltage inconsistencies in the TPS circuit.

Is it safe to drive with a P1121 code active?

Driving is possible but not recommended, as the vehicle may experience unpredictable throttle response or stalling, which could pose safety risks.

How do you fix the P1121 code on a Pontiac?

Repairs typically involve replacing a faulty throttle position sensor, repairing damaged wiring, cleaning the throttle body, or updating/replacing the ECM.

Do I need to clear the P1121 code after repairs?

Yes, after fixing the issue, clear the code using an OBDII scanner to ensure it doesnâ€™t reappear.

Can a failing TPS cause other engine-related issues?

Yes, a malfunctioning throttle position sensor can lead to poor engine performance, increased emissions, and potential damage to other components over time.

What tools are needed to fix the P1121 code on a Pontiac?

Basic tools include an OBDII scanner, multimeter for voltage testing, and possibly a socket set for removing and replacing the throttle position sensor.