Function Explanation (DTC Detection Outline)
- The PCM detects the oxygen concentration in the exhaust gas from the A/F sensor signal and performs fuel injection amount feedback to maintain the optimum air/fuel ratio. If a condition in which the feedback correction amount is large (fuel injection amount being increased) continues for the specified time, a feedback correction amount malfunction is determined, and a DTC is stored. The feedback correction amount has a "Fuel feedback correction amount" for the air/fuel ratio and a "Fuel learning correction amount" for fuel injector deterioration over time.
- "Fuel feedback correction amount (SHRT_FUEL_TRIM)" and "Fuel learning correction amount (LONG_FUEL_TRIM)" can be verified from the M-MDS PID item.
- The sum of the fuel feedback correction amount (SHRT_FUEL_TRIM) and the fuel learning correction amount (LONG_FUEL_TRIM) is the specified value (30 %) or more, and 10 s or more have elapsed with the fuel learning correction amount (LONG_FUEL_TRIM) at the specified value (15 %) or more. Engine coolant temperature:0-45°C {32-113°F}, 60°C {140°F} or more
- The fuel feedback correction amount reaches the upper limit (25% or more) for 20 s or more. Engine coolant temperature:0-45°C {32-113°F}, 60°C {140°F} or more