Subaru LEGACY 2003 Service Manual page 62

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
1 CHECK CONDITION OF CRANKSHAFT PO-
SITION SENSOR INSTALLATION.
Are the crankshaft position sensor installing
bolts tightened securely?
2 CHECK CRANKSHAFT POSITION SENSOR.
1) Remove crankshaft position sensor.
2) Measure resistance between connector ter-
minals of crankshaft position sensor.
Terminals
No. 1 — No. 2:
Is the measured value within the specified
value?
3 CHECK HARNESS BETWEEN ECM AND
CRANKSHAFT POSITION SENSOR CON-
NECTOR.
1) Connect connector to crankshaft position
sensor.
2) Disconnect connector from ECM.
3) Measure resistance of harness between
crankshaft position sensor connector and
ECM.
Connector & terminal
(B135) No. 8 — (B135) No. 2 (With
immobilizer)
(B135) No. 8 — (B135) No. 1 (Without
immobilizer)
Is the measured value within the specified
value?
4 CHECK HARNESS BETWEEN ECM AND
CRANKSHAFT POSITION SENSOR CON-
NECTOR.
Measure resistance of harness between ECM
connector and chassis ground.
Connector & terminal
(B135) No. 8 — Chassis ground:
Is the measured value less than the specified
value?
5 CHECK INPUT SIGNAL FOR ECM.
1) Turn ignition switch to OFF.
2) Set the positive (+) probe and ground lead
of oscilloscope at ECM connector termi-
nals.
3) Measure voltage indicated on oscilloscope
while cranking the engine.
Connector & terminal
(B135) No. 2 (+) — (B135) No. 8 ( − − − − ):
(With immobilizer)
(B135) No. 1 (+) — (B135) No. 8 ( − − − − ):
(Without immobilizer)
Does the measured value exceed the spec-
ified value?
6 CHECK POOR CONTACT.
Check poor contact in ECM connector.
Is there poor contact in ECM connector?
Step
EN(H4SOw/oOBD)-60
Value
Installing bolts are securely
tightened.
1 — 4 kΩ
1 — 5 kΩ
10 Ω
400 mV
There is poor contact.
Yes
Go to step 2. Tighten crank-
shaft position sen-
sor installing bolts
securely.
Go to step 3. Replace crank-
shaft position sen-
sor.
Go to step 4. Repair harness
and connector.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
crankshaft posi-
tion sensor and
ECM connector
• Poor contact in
coupling connector
(B21)
Repair ground Go to step 5.
short circuit in har-
ness between
crankshaft posi-
tion sensor and
ECM connector.
Go to step 6. Replace crank-
shaft position sen-
sor.
Repair poor con- Go to step 7.
tact in ECM con-
nector.
No