AutoCodes – Cadillac – P1578 Cadillac

P1578 Cadillac Code - Brake Booster Vacuum Sensor Circuit Low Vacuum

Quick Answer

During engine speed at 500 rpm or more for 20 seconds, brakes not applied, BARO input at 72 kPa or more, MAP input at 60 kPa or less, the Powertrain Control Module (PCM) detects the Brake Booster Vacuum (BBV) input of 5 kPa or less for 16 seconds. Common causes include Faulty Brake Booster Vacuum (BBV) sensor, Brake Booster Vacuum (BBV) sensor harness is open or shorted, Brake Booster Vacuum (BBV) 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: P1578 Cadillac indicates Brake Booster Vacuum Sensor Circuit Low Vacuum.
Common causes: Common causes include Faulty Brake Booster Vacuum (BBV) sensor, Brake Booster Vacuum (BBV) sensor harness is open or shorted, Brake Booster Vacuum (BBV) 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 3,601

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 May 18, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
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Code P1578 Cadillac Description

OBDII Code P1578 Cadillac - Brake Booster Vacuum Sensor Circuit Low Vacuum - AutoCodes.com — P1578 Cadillac Code - Brake Booster Vacuum Sensor Circuit Low Vacuum

What does this mean?

What are the Possible Causes of the DTC P1578 Cadillac?

Faulty Brake Booster Vacuum (BBV) sensor
Brake Booster Vacuum (BBV) sensor harness is open or shorted
Brake Booster Vacuum (BBV) sensor circuit poor electrical connection

How to Fix the DTC P1578 Cadillac?

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 P1578 Cadillac 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.