DTC EFI-232
2-3-1 LONG-TERM FUEL TRIM, PART LOAD2-3-2 LONG-TERM FUEL TRIM, IDLING
Trouble Code Conditions
- The engine control module (ECM) receives information from the heated oxygen sensor (HO2S) about the fuel/air mixture in the idling and partial load ranges. If the fuel/air mixture deviates from Lambda, the short term fuel trim will compensate for this by adjusting injection time so that Lambda = 1 is achieved. When the short-term fuel trim makes an adjustment,the integrator median must be adjusted by the long-term trim. When the long-term fuel trim has adapted the short-term trim to a maximum value, diagnostic trouble code (DTC) EFI-232 (idling range 0.48 ms +/- 0.40 ms) or diagnostic trouble code EFI-231 (part load range 0.773 - 1.227) and status message Upper Limit (lean fuel/air mixture) or Lower Limit (rich fuel/air mixture) are stored.
Substitute value(s)
- None.
Possible source(s)
Upper limit:
- Defective mass air flow (MAF) sensor
- Low fuel pressure
- Air leakage
- Faulty sensor signals.
Lower limit:
- Defective mass air flow sensor.
- High fuel pressure.
- Leaking injectors.
- Leaking EVAP system.
- Contaminated engine oil.
- Oil level too high.
- Faulty sensor signals.
Fault symptom(s)
- Can result in high fuel consumption
- May result in poor performance.