Subaru Forester 2004 Service Manual page 190

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of throttle position sensor
signal using Subaru Select Monitor or OBD-II
general scan tool.
NOTE:
• Subaru Select Monitor
For detailed operation procedure, refer to
"READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE". <Ref. to EN(H4DOTC
2.5)-27, Subaru Select Monitor.>
• OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.
2 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground while tumble generator
valve is fully closed.
Connector & terminal
(B136) No. 16 (+) — Chassis ground (
3 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 16 (+) — Chassis ground (
4 CHECK INPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 26 (+) — Chassis ground (
5 CHECK INPUT SIGNAL FOR ECM WITH
SUBARU SELECT MONITOR.
Measure the voltage between ECM connector
and chassis ground.
Check
Is the voltage less than 0.1 V? Go to step 2.
Is the voltage more than 4.5 V? Go to step 4.
−
):
Does the voltage change by
shaking the harness and con-
nector of ECM while monitoring
the value with voltage meter?
−
):
Is the voltage less than 0.1 V? Go to step 6.
−
):
Does the voltage change by
shaking the harness and con-
nector of ECM while monitoring
the value with Subaru Select
Monitor?
EN(H4DOTC 2.5)-189
ENGINE (DIAGNOSTIC)
Yes
Even if the mal-
function indicator
light illuminates,
the circuit has
returned to a nor-
mal condition at
this time. A tempo-
rary poor contact
of the connector
may be the cause.
NOTE:
In this case repair
the following:
• Poor contact in
throttle position
sensor connector
• Poor contact in
ECM connector.
• Poor contact in
coupling connector
Go to step 3.
Repair the poor Contact the SUB-
contact in ECM ARU dealer.
connector.
NOTE:
Inspection by DTM
is required, because
probable cause is
deterioration of mul-
tiple parts.
Go to step 5.
Repair the poor Go to step 6.
contact in ECM
connector.
No