Subaru 2009 IMPREZA, Service Manual

Page: 1538 / 3619

EN(H4DOTC)(diag)-317
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
15 CHECK REAR OXYGEN SENSOR DATA.
1) Warm up the engine until engine coolant
temperature is higher than 75°C (167°F), and
keep the engine speed at 3,000 rpm. (2 minutes
maximum)
2) Read the data of rear oxygen sensor signal
using Subaru Select Monitor or general scan
tool.
NOTE:
• Depress the clutch pedal. (MT model)
• Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-34, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedures, refer to the
general scan tool operation manual.
Is the voltage 490 mV or more? Go to step 16 . Go to step 17 .
16 CHECK REAR OXYGEN SENSOR DATA.
1) Warm up the engine until engine coolant
temperature is higher than 75°C (167°F), and
rapidly reduce the engine speed from 3,000
rpm.
2) Read the data of rear oxygen sensor signal
using Subaru Select Monitor or general scan
tool.
NOTE:
• Depress the clutch pedal. (MT model)
• Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-34, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedures, refer to the
general scan tool operation manual.
Is the voltage 250 mV or less? Go to step 18 . Go to step 17 .
17 CHECK REAR OXYGEN SENSOR CONNEC-
TOR AND COUPLING CONNECTOR. Has water entered the connec-
tor? Completely
remove any water
inside. Go to step 19 .
18 CHECK FRONT OXYGEN (A/F) SENSOR
AND REAR OXYGEN SENSOR DATA.
1) Warm up the engine until engine coolant
temperature is higher than 75°C (167°F), then
keep the engine idling for 5 minutes or more.
2) Read the data of rear oxygen sensor signal
using Subaru Select Monitor or general scan
tool.
NOTE:
• Subaru Select Monitor
For detailed operation procedures, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-34, Subaru Select Moni-
tor.>
• General scan tool
For detailed operation procedures, refer to the
general scan tool operation manual.
Is a voltage of 0.8 V or more
maintained for 5 minutes or
more? Replace the front
oxygen (A/F) sen-
sor. <Ref. to
FU(H4DOTC)-48,
Front Oxygen (A/F)
Sensor.> Go to step 19 .
Step Check Yes No