Engine-CodesBuick – P1121 Buick

P1121 Buick Code - Throttle Position Sensor Circuit Intermittent High Voltage

Quick Answer

The P1121 Buick diagnostic trouble code refers to an issue with the Throttle Position Sensor (TPS) circuit having intermittent high voltage. Common causes include Faulty throttle position sensor, Damaged wiring or connectors in the TPS circuit, Malfunctioning ECU. 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 Buick indicates Throttle Position Sensor Circuit Intermittent High Voltage.
Common causes
Common causes include Faulty throttle position sensor, Damaged wiring or connectors in the TPS circuit, Malfunctioning ECU.
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.
Table of contents Created and updated by William Orellana on Sep 10, 2024
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Code P1121 Buick Description

The P1121 Buick diagnostic trouble code refers to an issue with the Throttle Position Sensor (TPS) circuit having intermittent high voltage. The throttle position sensor is a crucial component of the vehicle's electronic fuel injection system, as it monitors the position of the throttle valve and sends signals to the engine control unit (ECU) to adjust fuel delivery and ignition timing accordingly. When the TPS circuit detects an intermittent high voltage, it means that there is a problem with the sensor's ability to accurately relay throttle position information to the ECU.

OBDII Code P1121 Buick - Throttle Position Sensor Circuit Intermittent High Voltage
P1121 Buick Code - Throttle Position Sensor Circuit Intermittent High Voltage

Common Causes of P1121 Buick

  1. Faulty throttle position sensor
  2. Damaged wiring or connectors in the TPS circuit
  3. Malfunctioning ECU
  4. Vacuum leak affecting TPS readings
  5. Corrosion or buildup on sensor terminals

Symptoms of P1121 Buick

  1. Hesitations or surging during acceleration
  2. Rough idling or stalling
  3. Poor fuel efficiency
  4. Check Engine Light illuminated
  5. Decreased engine performance

How to Fix P1121 Buick

  1. Diagnostic scan: Use a diagnostic scanner to retrieve the trouble codes and pinpoint the issue.
  2. Inspection: Inspect the throttle position sensor, wiring, and connectors for any signs of damage or wear.
  3. Replace TPS: If the sensor is faulty, replace it with a new one following manufacturer's guidelines.
  4. Repair wiring: Repair or replace any damaged wiring or connectors in the TPS circuit.
  5. Clear codes: Clear the trouble codes from the ECU and perform a test drive to ensure the issue is resolved.

Cost to Fix P1121 Buick

The typical repair costs for addressing a P1121 Buick code can vary depending on the specific cause of the issue and the cost of parts and labor in your area. Generally, replacing a throttle position sensor can cost between $100 and $200, while repairing wiring or connectors may add to the total cost. Labor rates at auto repair shops can range from $80 to $150 per hour, so it's advisable to check with local shops for a more accurate estimate based on your vehicle make and model.

When is the Code Detected?

When the Powertrain Control Module (PCM) senses a signal voltage higher than the normal operating range of the sensor, the P1121 will set.

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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.

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