P1127moderate severityPowertrain
Long Term Fuel Trim System Too Rich Bank 1
on 2005 Volkswagen Beetle 2.0L I4 · FWD
What this code means
The ECU detected that the long-term fuel trim for Bank 1 has exceeded the maximum rich correction limit. The engine is consistently receiving too much fuel and the adaptive system cannot compensate further.
Symptoms
- Check Engine Light
- Rich exhaust odor
- Black exhaust smoke
- Poor fuel economy
- Rough idle
Common causes
- Leaking fuel injectors
- Faulty fuel pressure regulator (excess pressure)
- O2 sensor reading false lean
- EVAP purge valve stuck open
- Coolant temperature sensor reading colder than actual
Diagnostic steps
- Monitor long-term and short-term fuel trims
- Test O2 sensor response time
- Check fuel pressure with gauge
- Inspect EVAP purge valve
- Test coolant temperature sensor
Repair notes
Identify and repair the root cause of excess fuel delivery on Bank 1.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1