Long Term Fuel Trim System Too Rich
2016-2021 Hyundai Tucson 2.0L I4
Description
The PCM has detected that the long-term fuel trim system correction has exceeded the rich limit. Similar to P1123 but applies to the overall system-level fuel trim rather than individual bank correction.
Symptoms
- Check Engine Light
- Poor fuel economy
- Black exhaust smoke
- Rich exhaust odor
- Rough idle
Common Causes
- Multiple leaking fuel injectors
- Fuel pressure regulator failure
- EVAP system purging excessively
- Faulty MAP or MAF sensor over-reporting airflow
- Stuck-open fuel injector
Diagnostic Steps
- Monitor system-level fuel trim on scan tool
- Compare bank-to-bank fuel trims
- Check fuel pressure at idle and under load
- Test EVAP purge valve for leaking
- Inspect fuel injectors for leaks
Repair Notes
Diagnose and repair the source of excess fuel delivery causing the rich system fuel trim.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
P1127 on Other Vehicles
Common Questions
What does code P1127 mean on a 2016-2021 Hyundai Tucson?
P1127 stands for "Long Term Fuel Trim System Too Rich". The PCM has detected that the long-term fuel trim system correction has exceeded the rich limit. Similar to P1123 but applies to the overall system-level fuel trim rather than individual bank correction.
What are the symptoms of P1127 on a Hyundai Tucson?
Common symptoms of P1127 include: Check Engine Light, Poor fuel economy, Black exhaust smoke, Rich exhaust odor, Rough idle.
What causes P1127 on a 2016-2021 Hyundai Tucson?
Common causes of P1127 include: Multiple leaking fuel injectors, Fuel pressure regulator failure, EVAP system purging excessively, Faulty MAP or MAF sensor over-reporting airflow, Stuck-open fuel injector.