Engine-CodesBuick – P1421 Buick

P1421 Buick Code - Intake Air Low Pressure Switch Circuit High Voltage

Quick Answer

The P1421 diagnostic trouble code for Buick vehicles indicates an issue with the Intake Air Low Pressure Switch Circuit High Voltage. Common causes include Faulty intake air low-pressure switch, Wiring issues in the circuit, Loose or corroded electrical connections. 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
P1421 Buick indicates Intake Air Low Pressure Switch Circuit High Voltage.
Common causes
Common causes include Faulty intake air low-pressure switch, Wiring issues in the circuit, Loose or corroded electrical connections.
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 P1421 Buick Description

The P1421 diagnostic trouble code for Buick vehicles indicates an issue with the Intake Air Low Pressure Switch Circuit High Voltage. This code is specifically related to the intake air system in the vehicle. The intake air system is crucial for delivering the right amount of air to the engine for combustion, which is essential for proper engine performance and fuel efficiency. The low-pressure switch in the intake air system is responsible for detecting the pressure of the incoming air and sending this information to the engine control module (ECM) for optimal fuel delivery.

OBDII Code P1421 Buick - Intake Air Low Pressure Switch Circuit High Voltage
P1421 Buick Code - Intake Air Low Pressure Switch Circuit High Voltage

Common Causes of P1421 Buick

  1. Faulty intake air low-pressure switch
  2. Wiring issues in the circuit
  3. Loose or corroded electrical connections
  4. ECM malfunction
  5. Air leaks in the intake system

Symptoms of P1421 Buick

  1. Decreased engine performance
  2. Reduced fuel efficiency
  3. Engine misfires
  4. Rough idling
  5. Check Engine Light illuminated on the dashboard

How to Fix P1421 Buick

  1. Begin by performing a thorough inspection of the intake air low-pressure switch and the surrounding wiring. Look for any signs of damage, corrosion, or loose connections.
  2. Test the intake air low-pressure switch using a multimeter to check for proper voltage output. Replace the switch if it is faulty.
  3. Inspect and repair any damaged wiring in the circuit. Ensure all connections are tight and secure.
  4. Clear the diagnostic trouble codes from the ECM using a scan tool and test drive the vehicle to confirm the issue has been resolved.
  5. If the problem persists, consult with a professional mechanic to further diagnose and repair any underlying issues with the intake air system.

Cost to Fix P1421 Buick

The typical repair costs for addressing the P1421 code in a Buick vehicle can range from $100 to $300, depending on the specific cause of the issue and the extent of repairs needed. This estimate includes the cost of parts such as the intake air low-pressure switch, wiring repairs, and labor charges. It is important to note that diagnostic time and labor rates at auto repair shops can vary, so it is advisable to check with local shops for a more accurate cost estimate.

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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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