Long Term Fuel Trim System Too Lean Bank 1
1998-2008 Volkswagen Pointer 1.8L I4 🇷🇺
Description
The ECU detected that the long-term fuel trim for Bank 1 has reached the maximum lean correction limit. The engine is not receiving enough fuel relative to the air charge, and the system cannot add more fuel.
Symptoms
- Check Engine Light
- Rough idle
- Hesitation on acceleration
- Lean misfire
- Poor fuel economy
Common Causes
- Vacuum leak on intake side
- Weak fuel pump
- Clogged fuel injectors
- MAF sensor under-reading
- Intake manifold gasket leak
Diagnostic Steps
- Perform smoke test for vacuum leaks
- Monitor fuel trim values
- Test fuel pressure
- Clean or test MAF sensor
- Inspect intake manifold gasket
Repair Notes
Repair vacuum leaks first; then address fuel delivery issues if trims remain lean.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P1128 on Other Vehicles
Volkswagen Arteon
2019-2024 2.0L Turbo I4
Volkswagen Atlas
2018-2024 2.0L Turbo I4
Volkswagen Atlas
2018-2024 3.6L V6
Volkswagen Atlas Cross Sport
2020-2024 2.0L Turbo I4
Volkswagen Atlas Cross Sport
2020-2024 3.6L V6
Volkswagen Beetle
2012-2019 2.0L Turbo I4
Volkswagen Beetle
2012-2019 2.5L I5
Volkswagen Beetle Turbo
2012-2018 2.0L Turbo I4
Common Questions
What does code P1128 mean on a 1998-2008 Volkswagen Pointer?
P1128 stands for "Long Term Fuel Trim System Too Lean Bank 1". The ECU detected that the long-term fuel trim for Bank 1 has reached the maximum lean correction limit. The engine is not receiving enough fuel relative to the air charge, and the system cannot add more fuel.
What are the symptoms of P1128 on a Volkswagen Pointer?
Common symptoms of P1128 include: Check Engine Light, Rough idle, Hesitation on acceleration, Lean misfire, Poor fuel economy.
What causes P1128 on a 1998-2008 Volkswagen Pointer?
Common causes of P1128 include: Vacuum leak on intake side, Weak fuel pump, Clogged fuel injectors, MAF sensor under-reading, Intake manifold gasket leak.