Subaru Impreza 2003 Service Manual page 1259

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
B: DTC P0021 — "A" CAMSHAFT POSITION-TIMING OVER-ADVANCED OR
SYSTEM PERFORMANCE (BANK 2) —
• DTC DETECTING CONDITION:
• Immediately at fault recognition
• TROUBLE SYMPTOM:
• Engine stalls.
• Erroneous idling
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOTC)-48, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)-40, Inspection Mode.>.
Step
1 CHECK ANY OTHER DTC ON DISPLAY.
2 CHECK CURRENT DATA.
1)Start the engine and let it idle.
2)Inspect the AVCS operating angle and vari-
able valve timing solenoid valve duty output
using Subaru Select Monitor and OBD-II gen-
eral scan tool.
NOTE:
•Subaru Select Monitor
For detailed operation procedure, refer to the
"READ CURRENT DATA FOR ENGINE".
<Ref. to EN(H4DOTC)-32, Subaru Select Mon-
itor.>
•OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Instruction Manual.
Check
Is any other DTC displayed?
Is the AVCS operating angle
more than approx. 0°C and the
variable valve timing solenoid
valve duty output more than
approx. 10%?
EN(H4DOTC)-83
ENGINE (DIAGNOSTICS)
Yes
Inspect the rele- Go to step 2.
vant DTC using
"List of Diagnostic
Trouble Code
(DTC)". <Ref. to
EN(H4DOTC)-75,
List of Diagnostic
Trouble Code
(DTC).>
Inspect the follow- A temporary mal-
ing items and function. Conduct
repair or replace if the following to
necessary. clean the oil pas-
• Engine oil sage.
(amount, con- Replace the
tamination) engine oil and idle
• Oil pipe (clog) the engine for 5
• variable valve minutes, then
timing solenoid replace the oil filter
valve (clog or and engine oil.
contamination
in oil passage,
settling at
spring, stuck at
valve)
• Intake cam-
shaft (sludge,
damage at
camshaft)
• Timing belt
(timing mark
aligning)
No