DTC B250 Dodge

Description

The fuel system diagnostic utilizes two separate monitors. The first monitor asseses the percentage of the long-term fuel adaptation. The second monitor asseses the percentage of the short-term FT’s physical limits. The short-term FT monitor is enabled in every engine state except for DFCO. The long-term FT monitor is enabled during its learning process and is inhibited during EVAP canister purge phases. Therefore, an additional learning process can be initiated when large short-term FT deviations occur and the assessment can be executed. Separate counters are started for both assessments. When neither a lean condition nor a rich condition is detected, the end diagnostic counter is decremented from a calibratable value to zero and a passing decision is made. When a lean condition is present and the total fuel control exceeds the calibrated threshold value, a time counter is incremented. When the time counter exceeds the calibrated threshold value, a lean error is set. When a rich condition is present and the total fuel control falls below the calibrated threshold value, a time counter is incremented. When the time counter exceeds the calibrated threshold value, a rich error is set. The time counters are incremented while the lambda controller or the lambda adaptation exceeds minimum or maximum threshold values. A malfunction is detected as soon as one of the time counters reaches its respective maximum value.