Subaru Impreza 2002 Service Manual page 264

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK CURRENT DATA.
1)Start the engine.
2)Measure the ignition timing advance using
Subaru Select Monitor or OBD-II general scan
tool, while running the vehicle at approx. 30
km/h (19 MPH).
NOTE:
•Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(TURBO)-34, Subaru Select Moni-
tor.>
•OBD-II scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Instruction Manual.
2 CHECK HARNESS BETWEEN VARIABLE
VALVE TIMING CAMSHAFT POSITION SEN-
SOR AND ECM CONNECTOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from variable
valve timing camshaft position sensor and
ECM.
3)Measure the resistance of harness between
variable valve timing camshaft position sensor
connector and engine ground.
Connector & terminal
(E35) No. 1 — (B84) No. 9:
(E35) No. 2 — (B84) No. 15:
3 CHECK HARNESS BETWEEN VARIABLE
VALVE TIMING CAMSHAFT POSITION SEN-
SOR AND ECM CONNECTOR.
Measure the resistance of harness between
variable valve timing camshaft position sensor
connector and engine ground.
Connector & terminal
(E35) No. 1 — Engine ground:
(E35) No. 2 — Engine ground:
4 CHECK CONDITION OF VARIABLE VALVE
TIMING CAMSHAFT POSITION SENSOR.
Check
Does the ignition timing
advance smoothly change,
according to engine output
change?
Idling: −2 — +2 degree
Vehicle running: −2 — +50
degree
Is the resistance less than 1
Ω?
Is the resistance more than 1M
Ω?
Is the variable valve timing
camshaft position sensor
installation bolt tightened
securely?
EN(TURBO)-27
ENGINE (DIAGNOSTICS)
Yes
Repair the poor Go to step 2.
contact in connec-
tor.
NOTE:
In this case, repair
the following:
• Poor contact in
variable valve tim-
ing camshaft posi-
tion sensor
• Poor contact in
ECM connector
Go to step 3. Repair the har-
ness and connec-
tor.
NOTE:
In this case, repair
the following:
• Open circuit in
harness between
variable valve tim-
ing camshaft posi-
tion sensor and
ECM connector
• Poor contact in
ECM connector
• Poor contact in
coupling connector
Go to step 4. Repair the ground
short circuit in har-
ness between vari-
able valve timing
camshaft position
sensor and ECM
connector.
NOTE:
The harness be-
tween both con-
nectors
shielded.
the ground short
circuit in harness
together
shield.
Go to step 5. Tighten the vari-
able valve timing
camshaft position
sensor installation
bolt securely.
No
are
Repair
with