Subaru 2009 IMPREZA Service Manual page 2503

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK POOR CONTACT OF CONNECTOR.
Check if there is poor contact between
VDCCM&H/U and ABS wheel speed sensor.
2 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 the 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:
3 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:
4 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 (–):
VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)
Check
Is there poor contact?
Is the resistance less than 0.5 ? Go to step 3.
Is the resistance 1 M or
more?
Is the voltage 5 — 16 V?
VDC(diag)-41
Yes No
Repair the connec- Go to step 2.
tor.
Repair the harness
connector between
VDCCM&H/U and
ABS wheel speed
sensor.
Go to step 4. Repair the harness
connector between
VDCCM&H/U and
ABS wheel speed
sensor.
Go to step 6. Go to step 5.