Function Explanation (DTC Detection Outline)

• The PCM diagnoses the turbo system performance by comparing the target air charging pressure with the actual.
• The PCM uses the MAP sensor to monitor the intake manifold pressure during boost control as the actual air charging pressure.
• When the monitoring conditions are met during boost control, the PCM compares the target air charging pressure with the actual. If the actual air charging pressure is higher than the specification for the target air charging pressure, the PCM determines an excess air charging malfunction.
• The PCM performs diagnosis when each of the preconditions during drive cycle is met. If a malfunction is detected, the malfunction detection counter begins counting up. The value of the malfunction detection counter is maintained while the preconditions are not being met. If the cumulative value of the malfunction detection counter exceeds the threshold during the first drive cycle, a malfunction is determined and a pending code is stored.
• If the PCM determines that the malfunction recurs from the next drive cycle and thereafter, it stores a DTC and turns on the check engine light.

Courtesy of MAZDA MOTORS CORP.

COMPONENT OPERATIONS

Component no	Refer to
1	Charging pressure [kPa]
2	Preconditions
3	Realization
4	Not realization
5	Target - Actual
6	Counter
7	DTC
8	Abnormal
9	Normal
10	Count up
11	Count down
12	Hold
13	Actual
14	Target
15	Pending code stored
16	Determined value
17	Threshold
18	Time [s]