AutoCodes – Generic – P257A

P257A Code - Vacuum Reservoir Control Circuit/Open

Quick Answer

The Engine Control Module (ECM) monitors the Vacuum Reservoir Control Circuit signal. Common causes include Faulty Vacuum Reservoir Control, Vacuum Reservoir Control harness is open or shorted, Vacuum Reservoir Control 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: P257A indicates Vacuum Reservoir Control Circuit/Open.
Common causes: Common causes include Faulty Vacuum Reservoir Control, Vacuum Reservoir Control harness is open or shorted, Vacuum Reservoir Control 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 5,875

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 Jan 19, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P257A Description

The Engine Control Module (ECM) monitors the Vacuum Reservoir Control Circuit signal. The ECM sets the OBDII code when the Vacuum Reservoir Control Circuit signal is out of factory specifications.

OBDII Code P257A - Vacuum Reservoir Control Circuit/Open - AutoCodes.com — P257A Code - Vacuum Reservoir Control Circuit/Open

What does this mean?

What are the Possible Causes of the DTC P257A?

Faulty Vacuum Reservoir Control
Vacuum Reservoir Control harness is open or shorted
Vacuum Reservoir Control circuit poor electrical connection

How to Fix the DTC P257A?

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 P257A 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.