Subaru IMPREZA 2002 Service Manual page 441

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Step
CHECK CURRENT DATA.
1)Start the engine.
2)Read the data of intake air temperature sen-
sor signal using Subaru Select Monitor or the
OBD-II general scan tool.
NOTE:
*Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE". <Ref.
to EN(S0HC)-32, Subaru Select Monitor.>
*OBD-ll general scan tool
For detailed operation procedure, refer to the
OBD-ll General Scan Tool Instruction Manual.
CHECK HARNESS BETWEEN INTAKE AIR
TEMPERATURE AND PRESSURE SENSOR
AND ECM CONNECTOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from intake air
temperature and pressure sensor.
3)Measure the voltage between intake air tem-
perature and pressure sensor connector and
engine ground.
Connector & terminal
(€20) No. 2 (+)
-
Engine ground (-):
CHECK HARNESS BETWEEN INTAKE AIR
TEMPERATURE AND PRESSURE SENSOR
AND ECM CONNECTOR.
1)Turn the ignition switch to ON.
2)Measure the voltage between intake air tem-
perature and pressure sensor connector and
engine ground.
Connector & terminal
(E20) No. 2 (+)
-
Engine ground ( - ) :
CHECK HARNESS BETWEEN INTAKE AIR
TEMPERATURE AND PRESSURE SENSOR
AND ECM CONNECTOR.
Measure the voltage between intake air tem-
perature and pressure sensor connector and
engine ground.
Connector & terminal
(E20) No. 2 (+)
-
Engine ground ( - ) :
Check
ithe value less than -40°C (-
D'F)?
;
the voltage more than 10 V?
;
the voltage more than 10 V?
s
the voltage more than 3 V?
Yes
io
to step 2.
lepair battery
hort circuit in har-
less between
itake air tempera-
Jre and pressure
ensor and ECM
onnector.
tepair battery
,hart
circuit in har.
less between
itake air tempera.
ure and pressure
;ensor and ECM
:onnector.
; o to step 5.
No
iepair poor con-
3ct.
IOTE:
i
this case, repaii
i e following:
Poor contact in
itake air tempera-
Jre and pressure
ensor
Poor contact in
C M
Poor contact in
oupling connectoi
B21)
Poor contact in
lint connector
B83), (8122)
io to step
3 .
; o
to step 4.
3epair harness
2nd connector.
\JOTE:
n this case, repai
he following:
1
Open circuit in
iarness between
ntake air tempera
ure and pressure
;ensor and ECM
:onnector
1
Poor contact in
ntake air tempera
.ure and pressure
sensor
I
Poor contact in
ECM
1
Poor contact in
:oupling connect0
[B21)
1
Poor contact in
oint connector
(883) and (8122)
EN(S0HC)-117