Subaru Legacy 2004 Service Manual page 3201

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)
Step
1 CHECK STOP LIGHT SWITCH CIRCUIT.
Check stop light switch open circuit.
2 CHECK PRESSURE SENSOR POWER SUP-
PLY.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from pressure
sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between pressure
sensor connector and chassis ground.
Connector & terminal
(B348) No. 3 (+) — Chassis ground (
3 CHECK OUTPUT VOLTAGE OF VDCCM&H/
U.
Measure the voltage between VDCCM&H/U
and chassis ground.
Connector & terminal
(B310) No. 27 (+) — Chassis ground (
4 CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in con-
5 CHECK GROUND CIRCUIT OF PRESSURE
SENSOR.
Measure the resistance between pressure
sensor and chassis ground.
Connector & terminal
(B348) No. 1 — Chassis ground:
6 CHECK GROUND CIRCUIT OF VDCCM&H/U.
Measure the resistance between VDCCM&H/U
and chassis ground.
Connector & terminal
(B310) No. 12 — Chassis ground:
7 CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in con-
8 CHECK PRESSURE SENSOR HARNESS.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from VDCCM&H/
U.
3) Measure the resistance between
VDCCM&H/U and pressure sensor.
Connector & terminal
(B310) No. 11 — (B348) No. 2:
9 CHECK GROUND SHORT OF HARNESS.
Measure the resistance between VDCCM&H/U
connector and chassis ground.
Connector & terminal
(B310) No. 11 — Chassis ground:
10 CHECK VDCCM&H/U.
1) Connect all the connectors.
2) Erase the memory.
3) Perform the inspection mode.
4) Read the DTC.
Check
Is the stop light switch circuit
OK?
Is the voltage 4.75 — 5.25 V? Go to step 5.
#
):
Is the voltage 4.75 — 5.25 V? Repair the har-
#
):
nector?
Is the resistance less than 0.5
&?
Is the resistance less than 0.5
&?
nector?
Is the resistance less than 0.5
&?
Is the resistance more than 1
M&?
Is DTC displayed?
VDC(diag)-128
Yes
Go to step 2. If there is malfunc-
tion in the stop
light switch circuit,
DTC may be
recorded in the
memory.
Go to step 3.
Go to step 4.
ness between
pressure sensor
and VDCCM&H/U.
Correct or replace Go to step 10.
the connector.
Go to step 8. Go to step 6.
Repair the har- Go to step 7.
ness between
pressure sensor
and VDCCM&H/U.
Correct or replace Go to step 10.
the connector.
Go to step 9. Repair the har-
ness between yaw
rate & lateral G
sensor and
VDCCM&H/U.
Go to step 10. Repair the har-
ness between yaw
rate & lateral G
sensor and
VDCCM&H/U.
Replace the Go to step 11.
VDCCM&H/U.
<Ref. to VDC-7,
VDC Control Mod-
ule & Hydraulic
Control Unit
(VDCCM&H/U).>
No