Subaru 2009 IMPREZA Service Manual page 2525

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK VDCCM&H/U INPUT VOLTAGE.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from the
VDCCM&H/U.
3) Run the engine at idle.
4) Measure the voltage between VDCCM&H/U
connector and chassis ground.
Connector & terminal
(B310) No. 28 (+) — Chassis ground (–):
(B310) No. 24 (+) — Chassis ground (–):
2 CHECK VDCCM&H/U INPUT VOLTAGE.
Calculate the voltage difference measured in
step 1.
A: (B310) No. 28 (+) — Chassis ground (–):
B: (B310) No. 24 (+) — Chassis ground (–):
3 CHECK VDCCM&H/U GROUND CIRCUIT.
1) Turn the ignition switch to OFF.
2) Measure the resistance between
VDCCM&H/U connector and chassis ground.
Connector & terminal
(B310) No. 25 — Chassis ground:
4 CHECK VDCCM&H/U VALVE RELAY.
Measure the resistance between VDCCM&H/U
connector terminals.
Connector & terminal
(B310) No. 24 — (B310) No. 25:
5 CHECK POOR CONTACT OF CONNEC-
TORS.
6 CHECK VDCCM&H/U.
1) Connect all connectors.
2) Clear the memory. <Ref. to VDC(diag)-24,
Clear Memory Mode.>
3) Perform the Inspection Mode. <Ref. to
VDC(diag)-23, Inspection Mode.>
4) Read the DTC.
7 CHECK OTHER DTC DETECTION.
VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)
Check
Is the voltage 10 — 15 V?
Is the voltage difference
between A and B 2 V or more?
Is the resistance less than 0.5 ? Go to step 4.
Is the resistance 1 M or
more?
Is there poor contact of connec-
tor between generator, battery
and VDCCM&H/U?
Is the same DTC displayed?
Is any other DTC displayed?
VDC(diag)-63
Yes No
Go to step 2. Repair the power
supply circuit.
Repair the power Go to step 3.
supply circuit.
Repair the
VDCCM&H/U
ground harness.
Go to step 5. Replace the
VDCCM&H/U.
<Ref. to VDC-7,
VDC Control Mod-
ule and Hydraulic
Control Unit
(VDCCM&H/U).>
Repair the connec- Go to step 6.
tor.
Replace the Go to step 7.
VDCCM only.
<Ref. to VDC-9,
REPLACEMENT,
VDC Control Mod-
ule and Hydraulic
Control Unit
(VDCCM&H/U).>
Perform the diag- Temporary poor
nosis according to contact occurs.
DTC. <Ref. to
VDC(diag)-33, List
of Diagnostic Trou-
ble Code (DTC).>