AutoCodes – Volkswagen – P1123 Volkswagen

P1123 Volkswagen Code - Long Term Fuel Trim Adjustment Bank 1 System Too Rich

Quick Answer

P1123 Volkswagen indicates Long Term Fuel Trim Adjustment Bank 1 System Too Rich. Common causes include Faulty HO2S, Faulty Mass Air Flow Sensor, High fuel pressure. 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: P1123 Volkswagen indicates Long Term Fuel Trim Adjustment Bank 1 System Too Rich.
Common causes: Common causes include Faulty HO2S, Faulty Mass Air Flow Sensor, High fuel pressure.
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 4,518

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 Apr 25, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1123 Volkswagen Description

OBDII Code P1123 Volkswagen - Long Term Fuel Trim Adjustment Bank 1 System Too Rich - AutoCodes.com — P1123 Volkswagen Code - Long Term Fuel Trim Adjustment Bank 1 System Too Rich

What does this mean?

What are the Possible Causes of the DTC P1123 Volkswagen?

Faulty HO2S
Faulty Mass Air Flow Sensor
High fuel pressure
Canister purge solenoid stuck open
HO2S harness is open or shorted
HO2S circuit poor electrical connection

How to Fix the DTC P1123 Volkswagen?

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 P1123 Volkswagen 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.