Initial-Set Function; Monitor Function; Fail-Safe Function - Mazda RX-8 2004 Service Highlights

Initial-set Function

• Reverses the stepping motor 60 steps at engine start, and detects the 0-step position.
• The 0-step position becomes the reference for the
regular drive function.

Monitor Function

• When the following conditions are met and after the initial-set function is completed, the monitor function
activates.
— Ignition switch at ON for 12th time.
— When the battery terminals are connected.
• The PCM monitors the stepping motor position when the position switch is on. The monitor method is as
follows:
— The stepping motor is rotated 60 steps clockwise from the 0-step position after the initial-set function, the
step number is counted until the position switch turns on.
• The position switch is on above step 52. However, if the on position for the position switch is not detected
above step 52, a malfunction of the stepping motor is determined and the fail-safe function is activated.
ENGINE SPEED
ABOVE STEP 52
STEPPING
MOTOR
METERING OIL
PUMP POSITION
SWITCH

Fail-safe Function

• When the stepping motor is determined to be malfunctioning by the monitor function, the fail-safe function is
activated.
• The fail-safe function controls fuel injection time, ignition timing, the target step for the stepping motor as
indicated in the table below, and controls engine output to protect the engine. Due to this, burning of engine
seals is prevented.
• Ineffective injection time is determined according to battery voltage and lengthens as battery voltage becomes
lower.
CONTROL SYSTEM
APPROX.
500 RPM
INITIAL-SET
FUNCTION
STEP 0
OFF
ON
ENGINE SPEED
APPROX.
500 RPM
STEPPING
MOTOR
STEP 0
REGULAR DRIVE FUNCTION
LEARNING FUNCTION
INITIAL-SET
REGULAR DRIVE
FUNCTION
FUNCTION
CHU0140S028
CHU0140S029
01–40–33
01–40