Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 553

VDC(diag)-111

General Diagnostic Table

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Vibration or
noise
• When braking
suddenly
• When accel-
erating sud-
denly
• While driving
on a slippery
road

Excessive
brake pedal
vibration

• Road surface (uneven)
• Incorrect wiring or piping connections

• VDCCM&H/U
• Brake booster
• Suspension play or fatigue (reduced damping)

Noise from
VDCH/U

• VDCCM&H/U (mount bushing)
• Defective ABS wheel speed sensor or
sensor gap
• Brake pipe

• VDCCM&H/U
• Defective steering angle sensor or improper
neutral position
• Defective yaw rate & G sensor or improper
installation

Noise from the
front side of
vehicle

• VDCCM&H/U (mount bushing)
• Defective ABS wheel speed sensor or
sensor gap
• Master cylinder
• Brake caliper
• Brake pad
• Disc rotor
• Brake pipe
• Brake booster
• Suspension play or fatigue (reduced
damping)

• Axle and wheels
• Tire specifications, tire wear and air pressures

Noise from the
rear side of
vehicle

• Defective ABS wheel speed sensor or
sensor gap
• Brake caliper
• Brake pad
• Disc rotor
• Parking brake
• Brake pipe
• Suspension play or fatigue (reduced
damping)

• Axle and wheels
• Tire specifications, tire wear and air pressures

Engine does not accelerate or
goes into a stall when accelerat-
ing suddenly or driving on a slip-
pery surface.

• VDCCM&H/U
• Defective ABS wheel speed sensor or
sensor gap
• Master cylinder
• Brake caliper
• Parking brake
• Incorrect wiring or piping

• Defective steering angle sensor or improper
neutral position
• Defective yaw rate & G sensor or improper
installation
• Brake pad
• Brake pipe

Symptoms

Main probable cause

Other probable cause

VDC(diag)-112

General Diagnostic Table

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Poor change-
direction-opera-
tion stability of
TCS

Deviation to
right or left
direction

• VDCCM&H/U
• Defective ABS wheel speed sensor or
sensor gap
• Defective steering angle sensor or
improper neutral position
• Defective yaw rate & G sensor or
improper installation
• Brake caliper
• Brake pad
• Wheel alignment
• Road surface (uneven)
• Road with crowns or banks
• Tire specifications, tire wear and air
pressures
• Incorrect wiring or piping connections

• Disc rotor
• Brake pipe
• Axle and wheels
• Suspension play or fatigue (reduced damping)

Vehicle spin

• VDCCM&H/U
• Defective ABS wheel speed sensor or
sensor gap
• Defective steering angle sensor or
improper neutral position
• Defective yaw rate & G sensor or
improper installation
• Brake pad
• Tire specifications, tire wear and air
pressures
• Incorrect wiring or piping connections

• Brake caliper
• Brake pipe

Steering wheel drag while driving

• VDCCM&H/U
• Defective ABS wheel speed sensor or
sensor gap
• Defective steering angle sensor or
improper neutral position
• Defective yaw rate & G sensor or
improper installation
• Incorrect wiring or piping connections
• Power steering system

• Brake caliper
• Brake pad
• Disc rotor
• Wheel alignment
• Road surface (uneven)
• Road with crowns or banks
• Suspension play or fatigue (reduced damping)
• Tire specifications, tire wear and air pressures

VDC operates while driving nor-
mally.

• VDCCM&H/U
• Defective ABS wheel speed sensor or
sensor gap
• Defective steering angle sensor or
improper neutral position
• Defective yaw rate & G sensor or
improper installation
• Wheel alignment
• Road surface (uneven)
• Road with crowns or banks
• Suspension play or fatigue (reduced
damping)
• Tire specifications, tire wear and air
pressures
• Incorrect wiring or piping connections
• Power steering system

Symptoms

Main probable cause

Other probable cause

VDC(diag)-113

General Diagnostic Table

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

VDC OFF indicator light does not
illuminate when the VDC OFF
switch is depressed. (5MT model)
NOTE:

When pressing VDC OFF switch
for 10 seconds or more, VDC OFF
indicator light goes off and cannot
operate any more. When turning
the ignition switch from OFF to
ON, the previous status is re-
stored.

• Harness
• Combination meter
• VDC OFF switch

VDC traction mode indicator light
does not illuminate when the VDC
OFF switch is depressed. (6MT
model)
NOTE:

When the VDC OFF switch is
pressed for 10 seconds or more,
the VDC traction mode indicator
light goes off, and operation can-
not be continued. When turning
the ignition switch from OFF to
ON, the previous status is re-
stored.

• Harness
• Combination meter
• VDC OFF switch

Symptoms

Main probable cause

Other probable cause

VDC(diag)-114

General Diagnostic Table

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)