Subaru IMPREZA 2002 Service Manual page 591

DIAGNOSTIC PROCEDURE WI
Go to step 5. Repair open circuii
between ECM and
front oxygen (NF)
t
sensor.
m
ITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Yes
Check
Does the Subaru Select Moni- Inspect DTC
tor or OBD-ll general scan tool PO131, P0132,
indicate DTC PO1 31, PO1 32, PO031 or PO032
PO031 or P0032? using "List of Diag-
nostic Trouble
Code (DTC)".
<Ref. to
List of Diagnostic
Trouble Code
(DTC).>
Go to step 3 .
EN(S0HC)-77,
s
the value equal to or more
han 0.85 and equal to less
han 1 .I 5 in idling?
~
Step
CHECK ANY OTHER DTC ON DISPLAY.
No
Go to step 2.
Go to step 4.
CHECK FRONT OXYGEN (NF) SENSOR DA-
TA.
1)Start the engine.
2)While observing the Subaru Select Monitor
or OBD-ll general scan tool screen, warm-up
the engine until coolant temperature is above
70°C (1 60°F).
If the engine is already warmed-up, operate at
idle speed for at least 1 minute.
3)Read the data of front oxygen (NF) sensor
signal using Subaru Select Monitor or 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-II general scan tool
For detailed operation procedures, refer to the
OBD-ll General Scan Tool Instruction Manual.
CHECK FRONT OXYGEN (NF) SENSOR D A
TA.
Race the engine at speeds from idling to 5,00(
rpm for a total of 5 cycles.
Is the value more than I .I f o r i
moment?
NOTE:
To increase engine speed to 5,000 rpm, slow1
30 to step 6.
depress accelerator pedal, taking approximatc
ly 5 seconds, and quickly release acceleratc
pedal to decrease engine speed.
CHECK HARNESS BETWEEN ECM AND
FRONT OXYGEN (NF) SENSOR.
1)Turn the ignition switch to OFF.
2)Disconnect the connector from ECM and
front oxygen (NF) sensor connector.
3)Measure the resistance between ECM and
front oxygen (NF) sensor.
Connector & terminals
1
(9136) NO. 6
-
(€24) NO. 3:
(9136) NO. 7
-
(E24) NO. 4:
(9 136) NO. 19
-
(E24) NO. 1:
(9136) NO. 20
-
(E24) NO. 6:
Go to step 4.
Is the resistance less than 5
a?
EN(S0HC)-267