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2011 HYUNDAI TUCSON

2.0L I4AWDAUTOMATICgas
5 active safety recalls on this vehicle — view recalls
Repairs0Labor986Torque9872Fluid15DTC1786Battery0Maintenance0Recalls5
P1128moderate severityPowertrain

Long Term Fuel Trim System Too Lean

on 2011 Hyundai Tucson 2.0L I4 · AWD

What this code means

The PCM has detected that the long-term fuel trim system correction has exceeded the lean limit. The entire fuel system is consistently lean beyond the PCM correction capability.

Symptoms

  • Check Engine Light
  • Rough idle
  • Hesitation
  • Poor acceleration
  • Possible misfires at idle

Common causes

  • Large vacuum leak
  • Failing fuel pump with low pressure
  • Clogged fuel filter
  • MAF sensor contamination under-reporting airflow
  • Intake gasket leak

Diagnostic steps

  1. Check system fuel trim values on scan tool
  2. Perform comprehensive vacuum leak test
  3. Test fuel pressure at idle and under load
  4. Clean or replace MAF sensor
  5. Inspect intake manifold gaskets

Repair notes

Find and repair the vacuum leak or fuel delivery issue causing the lean system fuel trim.

Other Powertrain codes on this vehicle

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