Subaru 2002 IMPREZA Service Manual page 901

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK CONDITION OF CRANKSHAFT PO-
SITION SENSOR INSTALLATION.
2 CHECK CRANKSHAFT POSITION SENSOR.
1)Remove the crankshaft position sensor.
2)Measure the resistance between connector
terminals of crankshaft position sensor.
Terminals
No. 1 — No. 2:
3 CHECK HARNESS BETWEEN ECM AND
CRANKSHAFT POSITION SENSOR CON-
NECTOR.
1)Connect the connector to crankshaft position
sensor.
2)Disconnect the connector from ECM.
3)Measure the resistance of harness between
crankshaft position sensor connector and
ECM.
Connector & terminal
•With Immobilizer
(B135) No. 8 — (B135) No. 2
•Without Immobilizer
(B135) No. 8 — (B135) No. 1
4 CHECK HARNESS BETWEEN ECM AND
CRANKSHAFT POSITION SENSOR CON-
NECTOR.
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)Set the positive (+) probe and ground lead of
oscilloscope at ECM connector terminals.
3)Measure the voltage indicated on oscillo-
scope while cranking engine.
Connector & terminal
•With Immobilizer
(B135) No. 2 (+) — (B135) No. 8 ( − − − − )
•Without Immobilizer
(B135) No. 1 (+) — (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(w/oOBD)-
30, OPERATION, Clear Memory Mode.>
3)Perform the inspection mode. <Ref. to EN(w/
oOBD)-28, OPERATION, Inspection Mode.>
4)Read any DTC on the display. <Ref. to
EN(w/oOBD)-26, OPERATION, Read Diag-
nostic Trouble Code (DTC).>
8 CHECK ANY OTHER DIAGNOSTIC TROU-
BLE CODES (DTCs) APPEARANCE.
Check
Are the crankshaft position
sensor installing bolts tight-
ened securely?
Is the resistance between 1
and 4 kΩ?
Is the resistance between 1
and 5 kΩ?
Is the resistance less than 10
Ω?
Is the voltage more than 400
mV?
Is there poor contact in ECM
connector?
Is the same DTC as in current
diagnosis still being output?
Is any other DTC displayed?
EN(w/oOBD)-67
ENGINE (DIAGNOSTICS)
Yes
Go to step 2. Tighten the crank-
shaft position sen-
sor installing bolts
securely.
Go to step 3. Replace the crank-
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
crankshaft posi-
tion sensor and
ECM connector
• Poor contact in
coupling connector
(B21)
Repair the ground Go to step 5.
short circuit in har-
ness between
crankshaft posi-
tion sensor and
ECM connector.
Go to step 6. Replace the crank-
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