Function Explanation (DTC Detection Outline)

WARNING: This page is about a different variant/trim than selected.

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 MMDS PID item.

The specified period of time has elapsed while the sum of the fuel feedback correction amount [SHRT_FUEL_TRIM] and the fuel learning correction amount [LONG_FUEL_TRIM] is the threshold or more and the fuel learning correction amount [LONG_FUEL_TRIM] is the threshold or more. Engine coolant temperature: 0-45°C {32-113°F}, 60°C {140°F} or more

Courtesy of MAZDA MOTORS CORP.

PCM COMPONENT OPERATIONS

Component No.	Refer to
1	Correction amount (%)
2	Threshold (%) of sum of fuel feedback correction amount [SHRT_FUEL_TRIM] and fuel learning correction amount [LONG_FUEL_TRIM]
3	Threshold (%) of fuel learning correction amount [LONG_FUEL_TRIM]
4	0 (%)
5	Sum of the fuel feedback correction amount [SHRT_FUEL_TRIM] and fuel learning correction amount [LONG_FUEL_TRIM] (abnormal)
6	Specified period of time or more
7	Fuel learning correction amount (abnormal)
8	Fuel learning correction amount (normal)
9	Sum of the fuel feedback correction amount [SHRT_FUEL_TRIM] and fuel learning correction amount [LONG_FUEL_TRIM] (normal)
10	Time

The specified period of time has elapsed while the fuel feedback correction amount reaches the maximum value. Engine coolant temperature: 0- 45°C {32-113°F}, 60°C {140°F} or more

Courtesy of MAZDA MOTORS CORP.

PCM COMPONENT OPERATIONS

Component No.	Refer to
1	Correction amount (%)
2	Upper limit value (%)
3	0 (%)
4	Specified period of time or more
5	Abnormal
6	Normal
7	Time