Fault Conditions

The 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=1, the short-term fuel trim will compensate for this by adjusting injection time so that lamda=1 is achieved. When the short-term fuel trim makes an adjustment, the integrator median must be adjusted by the long-term trim. If adaptation needs to adjust to close to its maximum DTC EFI-232 (idling range -0.48 ms to +0.40 ms) or DTC EFI-231 (part load range factor 0.773-1.227) and the status message Upper limit (lean fuel/air mixture) or Lower limit (rich fuel/air mixture) will be stored.