Volkswagen DTC P1129 – Long Term Fuel Trim B2 System Too Rich
DTC P1129 meaning on Volkswagen
DTC P1129 on a Volkswagen indicates that the Long Term Fuel Trim Bank 2 system is detecting a fuel mixture that is too rich. This means that there is an excessive amount of fuel being delivered to the engine in relation to the amount of air, leading to a rich air-fuel mixture.
Volkswagen DTC P1129 symptoms
Symptoms of DTC P1129 on a Volkswagen may include:
- Decreased fuel efficiency
- Black smoke from the exhaust
- Rough idling or stalling
- Check Engine Light illuminated
Volkswagen DTC P1129 causes
The common causes of DTC P1129 on a Volkswagen include:
- Faulty oxygen sensor
- Leaking fuel injectors
- Dirty or clogged air filter
- Issues with the fuel pressure regulator
Volkswagen DTC P1129 seriousness
While DTC P1129 may not cause immediate harm to the engine, it can lead to decreased fuel efficiency and increased emissions. Ignoring this issue can potentially cause damage to the catalytic converter over time.
How to diagnose DTC P1129 on Volkswagen
To diagnose DTC P1129 on a Volkswagen, you can perform the following steps:
- Use an OBD-II scanner to retrieve the fault code
- Inspect the oxygen sensor for proper functioning
- Check for any fuel leaks or issues with the fuel injectors
- Inspect the air filter for dirt or clogs
How to fix DTC P1129 on Volkswagen
To fix DTC P1129 on a Volkswagen, you can try the following solutions:
- Replace the faulty oxygen sensor
- Clean or replace clogged air filter
- Repair or replace leaking fuel injectors
- Check and adjust the fuel pressure regulator
How to erase DTC P1129 on Volkswagen
To erase DTC P1129 on a Volkswagen, you can clear the fault code using an OBD-II scanner. After fixing the underlying issue causing the rich fuel mixture, you can reset the Check Engine Light and the DTC P1129 code.
Recommended tools for Volkswagen diagnostics
Explore our expert picks: The Best OBD2 Scanners for 2025
Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter
Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.