AutoCodes – Buick – P1421 Buick

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

Quick Answer

P1421 Buick indicates Intake Air Low Pressure Switch Circuit High Voltage. Common causes include Faulty Intake Air Low Pressure Switch, Intake Air Low Pressure Switch harness is open or shorted, Intake Air Low Pressure Switch 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: P1421 Buick indicates Intake Air Low Pressure Switch Circuit High Voltage.
Common causes: Common causes include Faulty Intake Air Low Pressure Switch, Intake Air Low Pressure Switch harness is open or shorted, Intake Air Low Pressure Switch 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 3,017

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 22, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
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Code P1421 Buick Description

OBDII Code P1421 Buick - Intake Air Low Pressure Switch Circuit High Voltage - AutoCodes.com — P1421 Buick Code - Intake Air Low Pressure Switch Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P1421 Buick?

Faulty Intake Air Low Pressure Switch
Intake Air Low Pressure Switch harness is open or shorted
Intake Air Low Pressure Switch circuit poor electrical connection

How to Fix the DTC P1421 Buick?

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 P1421 Buick 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.