Subaru Impreza 2003 Service Manual page 839

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
2 CHECK CAMSHAFT POSITION SENSOR.
1)Remove the camshaft position sensor.
2)Measure the resistance between connector
terminals of camshaft position sensor.
Terminals
No. 1 — No. 2:
3 CHECK HARNESS BETWEEN ECM AND
CAMSHAFT POSITION SENSOR CONNEC-
TOR.
1)Connect the connector to camshaft position
sensor.
2)Disconnect the connector from ECM.
3)Measure the resistance of harness between
camshaft position sensor connector and ECM.
Connector & terminal
With Immobilizer
(B135) No. 8 — (B135) No. 1:
Without Immobilizer
(B135) No. 8 — (B135) No. 2:
4 CHECK HARNESS BETWEEN ECM AND
CAMSHAFT POSITION SENSOR CONNEC-
TOR.
Measure the resistance of harness between
ECM connector and chassis ground.
Connector & terminal
(B135) No. 8 — Chassis ground:
5 CHECK INPUT SIGNAL FOR ECM.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from ECM.
3)Set the oscilloscope probe at ECM connec-
tor terminal positive (+) and its ground lead at
negative (−).
4)Measure the voltage indicated on oscillo-
scope while cranking engine.
Connector & terminal
With Immobilizer
(B135) No. 1 (+) — (B135) No. 8 ( − − − − ):
Without Immobilizer
(B135) No. 2 (+) — (B135) No. 8 ( − − − − ):
6 CHECK POOR CONTACT.
Check poor contact in ECM connector.
7 CHECK ECM.
1)Connect all connectors.
2)Erase the memory. <Ref. to EN(H4SOw/
oOBD)-28, OPERATION, Clear Memory
Mode.>
3)Perform the inspection mode. <Ref. to
EN(H4SOw/oOBD)-26, OPERATION, Inspec-
tion Mode.>
4)Read any DTC on the display. <Ref. to
EN(H4SOw/oOBD)-24, OPERATION, Read
Diagnostic Trouble Code (DTC).>
8 CHECK ANY OTHER DTCs APPEARANCE. Is any other DTC displayed?
Check
Is the resistance 1 — 4 kΩ?
Is the resistance 1 — 5 kΩ?
Is the resistance less than 5
Ω?
Is the voltage more than 400
mV?
Is there poor contact in ECM
connector?
Is the same DTC as in the cur-
rent diagnosis still being out-
put?
EN(H4SOw/oOBD)-63
ENGINE (DIAGNOSTICS)
Yes
Go to step 3. Replace the cam-
shaft position sen-
sor.
Go to step 4. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
camshaft position
sensor and ECM
connector
• Poor contact in
coupling connector
(B21)
Repair the ground Go to step 5.
short circuit in har-
ness between
camshaft position
sensor and ECM
connector.
Go to step 6. Replace the cam-
shaft position sen-
sor.
Repair the poor Go to step 7.
contact in ECM
connector.
Replace the gen- Go to step 8.
erator.
Proceed with the A temporary poor
diagnosis corre- contact.
sponding to the
DTC.
No