Subaru Impreza 2003 Service Manual page 508

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK CURRENT DATA.
1)Start the engine.
2)Read the data of intake manifold absolute
pressure signal using Subaru Select Monitor or
OBD-II general scan tool.
NOTE:
•Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(H4SO)-31, Subaru Select Moni-
tor.>
•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 manifold
absolute pressure sensor connector.
3 CHECK OUTPUT SIGNAL FOR ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 3 (+) — Chassis ground ( − − − − ):
4 CHECK OUTPUT SIGNAL FOR ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B135) No. 3 (+) — Chassis ground ( − − − − ):
5 CHECK INPUT SIGNAL FOR ECM.
Measure the voltage between ECM and chas-
sis ground.
Connector & terminal
(B135) No. 15 (+) — Chassis ground ( − − − − ):
6 CHECK INPUT SIGNAL FOR ECM. (USING
SUBARU SELECT MONITOR)
Read the data of atmospheric absolute pres-
sure signal using Subaru Select Monitor.
NOTE:
•Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(H4SO)-31, Subaru Select Moni-
tor.>
Check
Is the measured value less
than 13.3 kPa (100 mmHg,
3.94 inHg)?
Is there poor contact in ECM or
manifold absolute pressure
sensor connector?
Is the voltage more than 4.5 V? Go to step 5.
Does the voltage change by
shaking the ECM harness and
connector?
Is the voltage less than 0.2 V? Go to step 7.
Is the measured value more
than 13.3 kPa (100 mmHg,
3.94 inHg) by shaking the har-
ness and connector of ECM?
EN(H4SO)-96
Yes
Go to step 3. Go to step 2.
Repair poor con- Even if malfunc-
tact in ECM or tion indicator light
manifold absolute lights up, the cir-
pressure sensor cuit has returned
connector. to a normal condi-
tion at this time.
Go to step 4.
Repair poor con- Contact with SUB-
tact in ECM con- ARU distributor
nector. service.
NOTE:
Inspection by DTM
is required,
cause
cause is deteriora-
tion of
parts.
Go to step 6.
Repair poor con- Go to step 7.
tact in ECM con-
nector.
No
be-
probable
multiple