EP Equipment CQD16, Service Manual

Page: 79 / 251

65
REV. 07/2016
OPERATING SYSTEM
6
6.6 Stepper Motor
Stepper motor provides the vehicle with steering
input signals.
6.6.1 Removal and Installation
See Section 6.1 .
6.6.2 Faults and Causes
1
Fault
Operate the steering wheel, the
vehicle does not respond to the
steering signal;
the instrument displays fault code:
STEER SENSOR KO
Cause
a. Stepper motor failure;
b. Stepper motor circuit not
conducted.
Checking
-
-
Check if the appearance of the stepper motor
and its wiring harness are in good condition,
and if the connectors are connected securely;
Check if the mechanical connection between
stepper motor and steering wheel is secure
and if there is loosening.
6.6.3 Checking and Testing
-
“STEPPER MOTOR”, turn the steering wheel,
if the voltage display is always "0", it indicates
that the stepper motor has no signal output
(see Section 8.12):
- mechanical loosening between steering wh-
eel and step motor;
- stepper motor failure or its circuit not condu-
cted.
Check if the circuit from controller to stepper
motor is conducted.
If the two circuits are conducted, but the fault
still exists, then replace the stepper motor.
6.6.4 Control Circuit Troubleshooting
Stepper Motor Control Circuit
(Figure 90310)
Check if the circuit is broken by using a multi-
meter:
-
- Set the multimeter to ON-OFF;
Check if #19/#20/#21/#83 circuit (circuit
between stepper motor and controller) is
conducted.
- Enter TESTER Menu (EPSAC0) to check the
stepper motor voltage:
Testing
Blue
White
Black
Red