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Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 539

VDC(diag)-55

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Step

Check

Yes

CHECK POOR CONTACT OF CONNECTOR.
Check if there is poor contact between
VDCCM&H/U and ABS wheel speed sensor.

Is there poor contact?

Repair the connec-
tor.

Go to step

CHECK HARNESS CONNECTOR BETWEEN
VDCCM&H/U AND ABS WHEEL SPEED
SENSOR.
1) Disconnect the connector (B310) from the
VDCCM&H/U.
2) Disconnect the connector from ABS wheel
speed sensor.
3) Measure the resistance between
VDCCM&H/U connector and ABS wheel speed
sensor connector.

Connector & terminal

DTC C0021

(B310) No. 6 — (B6) No. 1:
(B310) No. 5 — (B6) No. 2:

DTC C0023

(B310) No. 1 — (B15) No. 1:
(B310) No. 26 — (B15) No. 2:

DTC C0025

(B310) No. 4 — (R72) No. 1:
(B310) No. 3 — (R72) No. 2:

DTC C0027

(B310) No. 27 — (R73) No. 1:
(B310) No. 2 — (R73) No. 2:

Is the resistance less than 1 Ω? Go to step

Repair the harness
connector between
VDCCM&H/U and
ABS wheel speed
sensor.

CHECK GROUND SHORT OF HARNESS.
Measure the resistance between VDCCM&H/U
connector and chassis ground.

Connector & terminal

DTC C0021

(B310) No. 6 — Chassis ground:

DTC C0023

(B310) No. 1 — Chassis ground:

DTC C0025

(B310) No. 4 — Chassis ground:

DTC C0027

(B310) No. 27 — Chassis ground:

Is the resistance 1 MΩ or
more?

Go to step

Repair the harness
connector between
VDCCM&H/U and
ABS wheel speed
sensor.

CHECK ABS WHEEL SPEED SENSOR POW-
ER SUPPLY CIRCUIT.
1) Connect the VDCCM&H/U connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between ABS wheel
speed sensor connector and chassis ground.

Connector & terminal

DTC C0021

(B6) No. 2 (+) — Chassis ground (–):

DTC C0023

(B15) No. 2 (+) — Chassis ground (–):

DTC C0025

(R72) No. 2 (+) — Chassis ground (–):

DTC C0027

(R73) No. 2 (+) — Chassis ground (–):

Is the voltage 5 — 16 V?

Go to step

VDC(diag)-56

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

E: DTC C0022 FRONT RIGHT ABS SENSOR SIGNAL

NOTE:

For the diagnostic procedure, refer to “DTC C0028 REAR LEFT ABS SENSOR SIGNAL”. <Ref. to VDC(di-

ag)-57, DTC C0028 REAR LEFT ABS SENSOR SIGNAL, Diagnostic Procedure with Diagnostic Trouble

Code (DTC).>

F: DTC C0024 FRONT LEFT ABS SENSOR SIGNAL

NOTE:

For the diagnostic procedure, refer to “DTC C0028 REAR LEFT ABS SENSOR SIGNAL”. <Ref. to VDC(di-

ag)-57, DTC C0028 REAR LEFT ABS SENSOR SIGNAL, Diagnostic Procedure with Diagnostic Trouble

Code (DTC).>

G: DTC C0026 REAR RIGHT ABS SENSOR SIGNAL

NOTE:

For the diagnostic procedure, refer to “DTC C0028 REAR LEFT ABS SENSOR SIGNAL”. <Ref. to VDC(di-

ag)-57, DTC C0028 REAR LEFT ABS SENSOR SIGNAL, Diagnostic Procedure with Diagnostic Trouble

Code (DTC).>

CHECK VDCCM&H/U POWER SUPPLY CIR-
CUIT.
1) Turn the ignition switch to OFF.
2) Disconnect the VDCCM&H/U connector.
3) Turn the ignition switch to ON.
4) Measure the voltage between VDCCM&H/U
connector terminals.

Connector & terminal

(B310) No. 28 (+) — (B310) No. 25 (–):

Is the voltage 10 — 15 V?

Go to step

Check the genera-
tor, battery and
VDCCM&H/U
power supply cir-
cuit.

CHECK ABS WHEEL SPEED SENSOR SIG-
NAL.
1) Install the ABS wheel speed sensor.
2) Prepare an oscilloscope.
3) Check the ABS wheel speed sensor. <Ref.
to VDC-25, ABS WHEEL SPEED SENSOR,
INSPECTION, Front ABS Wheel Speed Sen-
sor.>

Is the pattern the same wave-
form as shown in the figure?

Go to step

Replace the ABS
wheel speed sen-
sor. <Ref. to VDC-
24, Front ABS
Wheel Speed Sen-
sor.>

CHECK VDCCM&H/U.
1) Connect all connectors.
2) Clear the memory. <Ref. to VDC(diag)-27,
Clear Memory Mode.>
3) Perform the Inspection Mode. <Ref. to
VDC(diag)-26, Inspection Mode.>
4) Read the DTC.

Is the same DTC displayed?

Replace the
VDCCM only.
<Ref. to VDC-12,
REPLACEMENT,
VDC Control Mod-
ule and Hydraulic
Control Unit
(VDCCM&H/U).>

Go to step

CHECK OTHER DTC DETECTION.

Is any other DTC displayed?

Perform the diag-
nosis according to
DTC. <Ref. to
VDC(diag)-48, List
of Diagnostic Trou-
ble Code (DTC).>

It results from a
temporary noise
interference.

Step

Check

Yes

VDC(diag)-57

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

H: DTC C0028 REAR LEFT ABS SENSOR SIGNAL

DTC DETECTING CONDITION:

• Defective ABS wheel speed sensor signal (noise, irregular signal, etc.)

• Defective harness connector

TROUBLE SYMPTOM:

• ABS does not operate.

• VDC does not operate.

Step

Check

Yes

CHECK OUTPUT OF ABS WHEEL SPEED
SENSOR USING SUBARU SELECT MONI-
TOR.
1) Select “Current Data Display & Save” on the
Subaru Select Monitor.
2) Read the defective ABS wheel speed sen-
sor output.

Does the speed indicated on
the display change in response
to the speedometer reading
during acceleration/decelera-
tion when the steering wheel is
in the straight-ahead position?

Go to step

CHECK POOR CONTACT OF CONNECTOR.
Turn the ignition switch to OFF.

Is there poor contact of connec-
tors between VDCCM&H/U and
ABS wheel speed sensor?

Repair the connec-
tor.

Go to step

CHECK CAUSE OF SIGNAL NOISE.
Make sure the radio wave devices and elec-
tronic components are installed correctly.

Are the radio wave devices and
electronic components
installed correctly?

Go to step

Install the radio
wave devices and
electronic compo-
nents properly.

CHECK CAUSE OF SIGNAL NOISE.
Check if the noise sources (such as an
antenna) are installed near the sensor harness.

Are noise sources installed?

Install the noise
sources apart from
sensor harness.

Go to step

Is the same DTC displayed?

Replace the
VDCCM only.
<Ref. to VDC-12,
REPLACEMENT,
VDC Control Mod-
ule and Hydraulic
Control Unit
(VDCCM&H/U).>

Go to step

CHECK OTHER DTC DETECTION.

Is any other DTC displayed?

Perform the diag-
nosis according to
DTC. <Ref. to
VDC(diag)-48, List
of Diagnostic Trou-
ble Code (DTC).>

It results from a
temporary noise
interference.

CHECK INSTALLATION OF ABS WHEEL
SPEED SENSOR.

Is the ABS wheel speed sensor
installation bolt tightened to 7.5
N·m (0.76 kgf-m, 5.5 ft-lb)?

Go to step

Tighten the ABS
wheel speed sen-
sor installation
bolts.

Does the oscilloscope indicate
the waveform pattern like
shown in the figure when the
tire is slowly turned? Does the
oscilloscope indication repeat
the waveform pattern like
shown in the figure when the
tire is slowly turned in equal
speed for one rotation or more?

Go to step

10.

Go to step

VDC(diag)-58

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

CHECK ABS WHEEL SPEED SENSOR OR
MAGNETIC ENCODER.

Are there foreign matter, break-
age or damage at the tip of ABS
wheel speed sensor or mag-
netic encoder?

Remove dirt thor-
oughly. Also
replace the ABS
wheel speed sen-
sor or magnetic
encoder as a unit
with hub unit bear-
ing if it is broken or
damaged.

Go to step

10.

CHECK CAUSE OF SIGNAL NOISE.
Make sure the radio wave devices and elec-
tronic components are installed correctly.

Are the radio wave devices and
electronic components
installed correctly?

Go to step

11.

Install the radio
wave devices and
electronic compo-
nents properly.

CHECK CAUSE OF SIGNAL NOISE.
Check if the noise sources (such as an
antenna) are installed near the sensor harness.

Are noise sources installed?

Install the noise
sources apart from
sensor harness.

Go to step

12.

Is the same DTC displayed?

Replace the
VDCCM only.
<Ref. to VDC-12,
REPLACEMENT,
VDC Control Mod-
ule and Hydraulic
Control Unit
(VDCCM&H/U).>

Go to step

13.

CHECK OTHER DTC DETECTION.

Is any other DTC displayed?

Perform the diag-
nosis according to
DTC. <Ref. to
VDC(diag)-48, List
of Diagnostic Trou-
ble Code (DTC).>

It results from a
temporary noise
interference.
NOTE:

Though  the  ABS
warning  light  re-
mains  on  at  this
time, this is normal.
Drive the vehicle at
12  km/h  (7  MPH)
or more in order to
turn  ABS  warning
light off. Be sure to
drive  the  vehicle
and check that the
warning  light  goes
off.

Step

Check

Yes

Content .. 537 538 539 540 ..