P1124moderate severityPowertrain
Long Term Fuel Trim Mixture Too Lean
on 2014 Hyundai Tucson 2.0L I4 · AWD
What this code means
The PCM has detected that the long-term fuel trim is correcting excessively in the rich direction, indicating the engine is running too lean. The fuel system is consistently delivering less fuel than needed.
Symptoms
- Check Engine Light
- Rough idle
- Hesitation on acceleration
- Poor performance
- Possible misfires
Common causes
- Vacuum leak in intake system
- Low fuel pressure (weak pump or clogged filter)
- Dirty or failing MAF sensor
- Exhaust leak before O2 sensor
- Clogged fuel injectors
Diagnostic steps
- Check long-term fuel trim values (excessively positive indicates lean correction)
- Perform smoke test for vacuum leaks
- Check fuel pressure under load
- Clean or test MAF sensor
- Check for exhaust leaks
Repair notes
Repair vacuum leaks or fuel delivery issues causing the lean condition.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1