Subaru Legacy 2002 Service Manual page 1326

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
No.
1 CHECK CURRENT DATA.
1) Start engine.
2) Read the data of intake manifold absolute
pressure signal using Subaru Select Monitor
or OBD-II general scan tool.
NOTE:
¼ Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(H6)-38, Subaru Select Monitor.>
¼ OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Instruction Manual.
2 CHECK POOR CONTACT.
Check poor contact in ECM and pressure
sensor connector.
3 CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 9 (+) — Chassis ground (−):
4 CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 9 (+) — Chassis ground (−):
5 CHECK INPUT SIGNAL FOR ECM.
Measure voltage between ECM and chassis
ground.
Connector & terminal
(B135) No. 8 (+) — Chassis ground (−):
6 CHECK INPUT SIGNAL FOR ECM. (USING
SUBARU SELECT MONITOR.)
Read data of atmospheric absolute pressure
signal using Subaru Select Monitor.
NOTE:
¼ Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(H6)-38, Subaru Select Monitor.>
7 CHECK HARNESS BETWEEN ECM AND
INTAKE MANIFOLD PRESSURE SENSOR
CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from intake manifold
pressure sensor.
3) Turn ignition switch to ON.
4) Measure voltage between intake manifold
pressure sensor connector and engine
ground.
Connector & terminal
(E21) No. 3 (+) — Engine ground (−):
Step
Is the value less than 1.7
kPa (13 mmHg, 0.51
inHg)?
Is there poor contact in
ECM or pressure sensor
connector?
Is the voltage more than
4.5 V?
Does the voltage change
more than 4.5 V by shaking
harness and connector of
ECM while monitoring the
value with voltage meter?
Is the voltage less than 0.7
V?
Does the value change
more than 1.7 kPa (13
mmHg, 0.51 inHg) by shak-
ing harness and connector
of ECM while monitoring
the value with Subaru
Select Monitor?
Is the voltage more than
4.5 V?
EN(H6)-119
Check Yes
Go to step 3.
Repair poor con-
tact in ECM or
pressure sensor
connector.
Go to step 5.
Repair poor con-
tact in ECM con-
nector.
Go to step 7.
Repair poor con-
tact in ECM con-
nector.
Go to step 8.
Engine (DIAGNOSTICS)
No
Go to step 2.
Even if MIL lights
up, the circuit has
returned to a nor-
mal condition at
this time.
Go to step 4.
Contact with your
Subaru distributor
service.
NOTE:
Inspection by
DTM is required,
because probable
cause is deterio-
ration of multiple
parts.
Go to step 6.
Go to step 7.
Repair open cir-
cuit in harness
between ECM
and intake mani-
fold pressure sen-
sor connector.