Subaru Legacy 2004 Service Manual page 642

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK ACCELERATOR POSITION SEN-
SOR OUTPUT.
1) Turn the ignition switch to ON.
2) Read the data of main accelerator position
sensor signal using Subaru Select Monitor.
2 CHECK POOR CONTACT.
Check poor contact in connector between
ECM and accelerator position sensor.
3 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Disconnect the connector from accelerator
position sensor.
4) Measure the resistance between ECM con-
nector and accelerator position sensor connec-
tor.
Connector & terminal
(B137) No. 31 — (B315) No. 4:
4 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR POSITION SENSOR.
1) Connect the ECM connector.
2) Measure the resistance between accelera-
tor position sensor connector and engine
ground.
Connector & terminal
(B315) No. 4 — Engine ground:
5 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR POSITION SENSOR.
1) Connect the ECM connector.
2) Turn the ignition switch to ON.
3) Measure the voltage between accelerator
position sensor connector and engine ground.
Connector & terminal
(B315) No. 5 (+) — Engine ground (
6 CHECK HARNESS BETWEEN ECM AND AC-
CELERATOR POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between ECM con-
nectors.
Connector & terminal
(B137) No. 29 — (B137) No. 25:
(B137) No. 29 — (B136) No. 17:
Check
Is the voltage less than 4.8 V? Go to step 2.
Is there poor contact?
Is the resistance less than 1
&?
Is the resistance less than 5
&?
Is the voltage less than 6 V?
"
):
Is the resistance more than 1
M&?
EN(H4SO 2.0)(diag)-210
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 poor
contact in ECM
connector.
Replace the ECM
if defective. <Ref.
to FU(H4SO 2.0)-
34, Engine Con-
trol Module
(ECM).>
Go to step 6. Repair the battery
short circuit in har-
ness between
ECM connector
and accelerator
position sensor
connector.
Repair the poor Repair the short
contact in acceler- circuit to sensor
ator position sen- power supply.
sor connector.
Replace the accel-
erator position
sensor if defective.
No