Subaru Forester 2004 Service Manual page 257

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTIC)
Step
14 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connector from the acceler-
ator pedal position sensor.
4) Measure the resistance between ECM con-
nector and accelerator pedal position sensor con-
nector.
Connector & terminal
(B136) No. 34 — (B315) No. 4:
(B136) No. 35 — (B315) No. 6:
15 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Connect the ECM connector.
2) Measure the resistance between accelera-
tor pedal position sensor connector and engine
ground.
Connector & terminal
(B315) No. 4 — Engine ground:
(B315) No. 6 — Engine ground:
16 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between accelerator
pedal position sensor connector and engine
ground.
Connector & terminal
(B315) No. 1 (+) — Engine ground (
(B315) No. 3 (+) — Engine ground (
4) Check the voltage change by shaking the
harness and connector of ECM while monitor-
ing the value with voltage meter.
17 CHECK POWER SUPPLY OF ACCELERA-
TOR PEDAL POSITION SENSOR.
1) Measure the voltage between accelerator
pedal position sensor connector and engine
ground.
Connector & terminal
(B315) No. 2 (+) — Engine ground (
(B315) No. 5 (+) — Engine ground (
2) Check the voltage change by shaking the
harness and connector of ECM while monitor-
ing the value with voltage meter.
18 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Connect the accelerator pedal position sen-
sor connector.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM connector
and chassis ground.
Connector & terminal
(B136) No. 17 (+) — Chassis ground (
(B136) No. 28 (+) — Chassis ground (
Check
Is the resistance less than 1
Ω?
Is the resistance less than 5
Ω?
Is the voltage less than 6 V?
−
):
−
):
Is the voltage less than 4.8 V? Go to step 18.
−
):
−
):
Is the voltage less than 4.8 V? Go to step 19.
−
):
−
):
EN(H4DOTC 2.5)-256
Yes
Go to step 15. Repair the open
circuit of harness
connector.
Go to step 16. Repair the poor
contact in ECM con-
nector. Replace the
ECM if defective.
Go to step 17. Repair battery short
circuit in harness
between ECM con-
nector and acceler-
ator pedal position
sensor connector.
Repair short circuit
in harness between
ECM connector and
accelerator pedal
position sensor con-
nector.
Repair poor contact
in accelerator pedal
position sensor con-
nector. Replace the
accelerator pedal
position sensor if
defective.
No