Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 250
EN(H4DOTC)(diag)-224
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
Step
Check
Yes
No
1
CHECK POWER SUPPLY OF CAMSHAFT
POSITION SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from camshaft
position sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between camshaft
position sensor connector and engine ground.
Connector & terminal
(E65) No. 1 (+) — Engine ground (–):
Is the voltage 10 V or more?
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit or
short circuit to
ground in harness
between main re-
lay connector and
camshaft position
sensor connector
• Poor contact of
coupling connector
2
CHECK HARNESS BETWEEN ECM AND
CAMSHAFT POSITION SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance between ECM con-
nector and camshaft position sensor connector.
Connector & terminal
(B137) No. 29 — (E65) No. 2:
(B137) No. 30 — (E65) No. 3:
Is the resistance less than 1 Ω? Go to step
Repair the harness
and connector.
NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM
connector
and camshaft posi-
tion sensor con-
nector
• Poor contact of
coupling connector
3
CHECK HARNESS BETWEEN ECM AND
CAMSHAFT POSITION SENSOR CONNEC-
TOR.
Measure the resistance between camshaft
position sensor connector and engine ground.
Connector & terminal
(E65) No. 2 — Engine ground:
Is the resistance 1 MΩ or
more?
Repair short circuit
to ground in har-
ness between
ECM connector
and camshaft posi-
tion sensor con-
nector.
4
CHECK HARNESS BETWEEN ECM AND
CAMSHAFT POSITION SENSOR CONNEC-
TOR.
Measure the voltage between camshaft posi-
tion sensor connector and engine ground.
Connector & terminal
(E65) No. 2 (+) — Engine ground (–):
Is the voltage 5 V or more?
Repair the short
circuit to power in
the harness
between ECM con-
nector and cam-
shaft position
sensor connector.
5
CHECK CONDITION OF CAMSHAFT POSI-
TION SENSOR.
Is the camshaft position sensor
installation bolt tightened
securely?
6
CHECK CAMSHAFT POSITION SENSOR.
Check the waveform of the camshaft position
sensor. <Ref. to EN(H4DOTC)(diag)-23,
Engine Control Module (ECM) I/O Signal.>
Is there any abnormality in
waveform?
Replace the cam-
shaft position sen-
sor. <Ref. to
FU(STI)-37, Cam-
shaft Position Sen-
sor.>
Repair the follow-
ing item.
• Poor contact of
ECM connector
• Poor contact of
camshaft position
sensor connector
• Poor contact of
coupling connector