Subaru 2009 IMPREZA Service Manual page 1315

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
ENGINE (DIAGNOSTICS)
D: DTC P0021 INTAKE CAMSHAFT POSITION - TIMING OVER-ADVANCED OR
SYSTEM PERFORMANCE (BANK 2)
DTC DETECTING CONDITION:
• Detected when two consecutive driving cycles with fault occur.
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-13, DTC P0021 INTAKE CAMSHAFT POSITION -
TIMING OVER-ADVANCED OR SYSTEM PERFORMANCE (BANK 2), Diagnostic Trouble Code (DTC) De-
tecting Criteria.>
TROUBLE SYMPTOM:
• Engine stalls.
• Improper idling
CAUTION:
After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-54,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-43, PROCE-
DURE, Inspection Mode.>.
Step
1 CHECK CURRENT DATA.
1) Start the engine and let it idle.
2) Check the AVCS system operating angle
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.
2 CHECK CURRENT DATA.
1) Drive with acceleration and deceleration at
80 km/h (50 MPH) or less.
NOTE:
Drive to an extent that the duty output of oil flow
control solenoid valve increases.
2) Measure the AVCS system operating angle
and oil flow control solenoid valve duty output
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.
Check
Is the AVCS system operating
angle approximately 0°?
When the oil flow control sole-
noid valve duty output exceeds
10%, is the AVCS system oper-
ating angle approx. 0°?
EN(H4DOTC)(diag)-94
Yes No
Go to step 2. Check the follow-
ing item and repair
or replace if neces-
sary.
• Oil pipe (clog)
• Oil flow control
solenoid valve
(clog or dirt of oil
routing, setting of
spring)
• Intake camshaft
(dirt, damage of
camshaft)
Check the follow- Perform the follow-
ing item and repair ing procedures,
or replace if neces- and clean the oil
sary. routing.
• Oil pipe (clog) Replace the
• Oil flow control engine oil and idle
solenoid valve the engine for 5
(clog or dirt of oil minutes, and then
routing, setting of replace the oil filter
spring) and engine oil.
• Intake camshaft <Ref. to
(dirt, damage of LU(H4SO)-9,
camshaft) REPLACEMENT,
Engine Oil.> <Ref.
to LU(H4SO)-21,
Engine Oil Filter.>