Subaru Forester 2004 Service Manual page 255

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTIC)
Step
1 CHECK ACCELERATOR PEDAL POSITION
SENSOR OUTPUT.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and terminal.
Connector & terminal
(B136) No. 17 (+) — (B136) No. 34 (
(B136) No. 28 (+) — (B136) No. 35 (
3) Check the voltage change by shaking the
harness and connector of ECM and accelera-
tor pedal position sensor connector and har-
ness.
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. 15 — (B315) No. 3:
(B136) No. 16 — (B315) No. 1:
(B136) No. 17 — (B315) No. 5:
(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. 15 — Chassis ground:
(B136) No. 16 — Chassis ground:
(B136) No. 17 — 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. 3 (+) — Engine ground (
(B315) No. 1 (+) — Engine ground (
4) Check the voltage change by shaking the
harness and connector of ECM while monitor-
ing the value with voltage meter.
6 CHECK ACCELERATOR PEDAL POSITION
SENSOR.
Measure the resistance of accelerator pedal
position sensor.
Terminals
No. 3 — No. 4:
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 1.2 — 4.8
kΩ?
EN(H4DOTC 2.5)-254
Yes
Go to step 3.
Repair the poor Go to step 12.
contact.
Go to step 4. Repair the open
circuit of harness
connector.
Go to step 5. Repair the ground
short circuit of har-
ness.
Go to step 6. Repair the poor
contact in ECM con-
nector. Replace the
ECM if defective.
Go to step 7. Replace the accel-
erator pedal posi-
tion sensor.
No