Subaru Forester 2004 Service Manual page 244

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
Step
1 CHECK ACCELERATOR PEDAL POSITION
SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector terminals.
Connector & terminal
(B136) No. 28 (+) — (B136) No. 35 (
3) Check the voltage exceed the standard
value by shaking the harness and connector of
ECM and accelerator pedal position sensor
connector and harness.
2 CHECK POOR CONTACT.
Check poor contact in connector between
ECM and accelerator pedal position sensor.
3 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. 16 — (B315) No. 1:
(B136) No. 28 — (B315) No. 2:
4 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR PEDAL POSITION SENSOR.
Measure the resistance between ECM connec-
tor and chassis ground.
Connector & terminal
(B136) No. 16 — Chassis ground:
(B136) No. 28 — Chassis ground:
5 CHECK POWER SUPPLY OF ACCELERA-
TOR 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 (
4) Check the voltage is within the specified
value when shaking the harness and connector
of ECM while monitoring the value with voltage
meter.
6 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor.
Terminals
No. 1 — No. 6:
Check
Is the voltage more than 0.4 V? Go to step 2.
−
):
Is there poor contact?
Is the resistance less than 1
Ω?
Is the resistance more than 1
MΩ?
Is the voltage 4.5 — 5.5 V?
−
):
Is the resistance 0.75 — 3.15
kΩ?
EN(H4DOTC 2.5)-243
ENGINE (DIAGNOSTIC)
Yes
Go to step 3.
Repair the poor Temporary poor
contact. contact occurred,
but it is normal at
present.
Go to step 4. Repair the open
circuit of harness
connector.
Go to step 5. Repair the chas-
sis short circuit of
harness.
Go to step 6. Repair the poor
contact in ECM
connector.
Replace the ECM
if defective.
Go to step 7. Replace the accel-
erator pedal posi-
tion sensor.
No