Maintenance Manual for Chery·Windcloud
MOTOROLA EFI System
9. Idle Speed Actuator Stepper Motor
DLA
Functions: there is a bypath air passage in
throttle valve casing, and engine speed can
be controlled by bypath airflow, while
bypath airflow is controlled by stepper
motor, which is located in bypath air
passage. ECU, according to signals sent by
sensors, is able to control engine speed
within the target speed range, which can be
calibrated in accordance with coolant
temperature.
Composition and principle: the nature of
stepper motor is a micro electrical machine,
which can rotate in different directions as
per its connecting with current of different
directions. The rotation axis of electrical
machine activates screw rod and indirectly
controls valve opening.
Failure diagnosis:
ECU can monitor short circuit, open circuit
status of two coils in idle speed stepper
motor, and lighten engine failure lamp when
such failure occurs, then engine enters
failure mode.
ECU is incapable of monitoring failure
caused by mechanical part of electrical
machine itself.
Idle speed actuator stepper motor
Idle speed stepper motor
Circuit diagram of idle speed actuator stepper motor
P
ins:
Pin 1 connecting with ECU’s A5# pin
Pin 2 connecting with ECU’s A6# pin
Pin 3 connecting with ECU’s A7# pin
Pin 4 connecting with ECU’s A8# pin
Troubleshooting: check if there is short
circuit or open circuit on the 4 lines
connecting stepper motor and ECU.
If there is clamping stagnation phenomenon
in stepper motor
If short circuit, open circuit occurs in
interior stepper motor.
Disassemble stepper motor, after electrification,
conduct electrical testing on stepper motor to see if
it has good flexibility.
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