AutoCodes – Volkswagen – P1129 Volkswagen

P1129 Volkswagen Code - Long Term Fuel Trim B2 System Too Rich

Quick Answer

The Engine Control Module (ECM) monitors the Long-Term Fuel Trim B2 System. Common causes include Faulty Oxygen Sensor, Faulty Mass Air Flow (MAF) 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: P1129 Volkswagen indicates Long Term Fuel Trim B2 System Too Rich.
Common causes: Common causes include Faulty Oxygen Sensor, Faulty Mass Air Flow (MAF) 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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 7,569

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 Jul 19, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P1129 Volkswagen Description

The Engine Control Module (ECM) monitors the Long-Term Fuel Trim B2 System. The ECM sets the OBDII code when the Long-Term Fuel Trim B2 System is not to factory specifications.

OBDII Code P1129 Volkswagen - Long Term Fuel Trim B2 System Too Rich - AutoCodes.com — P1129 Volkswagen Code - Long Term Fuel Trim B2 System Too Rich

What does this mean?

What are the Possible Causes of the DTC P1129 Volkswagen?

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

How to Fix the DTC P1129 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 P1129 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.

Need more information about the P1129 Volkswagen code?

Need more information on how to fix the P1129 Volkswagen code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1129 Volkswagen code diagnosed by a professional: Find a repair shop in your area

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.