Subaru 2004 LEGACY Service Manual page 4

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
B: DTC P0021 "A" CAMSHAFT POSITION - TIMING OVER-ADVANCED OR SYS-
TEM PERFORMANCE (BANK 2)
DTC DETECTING CONDITION:
Two consecutive driving cycles with fault
TROUBLE SYMPTOM:
• Engine stalls.
• Erroneous idling
CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H6DO)(diag)-40,
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H6DO)(diag)-33, Inspection
Mode.>.
Step
1 CHECK ANY OTHER DTC ON DISPLAY.
2 CHECK CURRENT DATA.
1) Start the engine and let it idle.
2) Measure the AVCS system operating angle
and oil flow control solenoid valve duty output
using Subaru Select Monitor or OBD-II general
scan tool.
NOTE:
• Subaru Select Monitor
For detailed operation procedures, refer to the
"READ CURRENT DATA SHOWN ON DIS-
PLAY FOR ENGINE". <Ref. to
EN(H6DO)(diag)-25, Subaru Select Monitor.>
• OBD-II general scan tool
For detailed operation procedures, refer to the
OBD-II General Scan Tool Operation Manual.
Check
Is any other DTC displayed?
Is the AVCS system operating
angle approx. 0 deg., and oil
flow control solenoid valve duty
output approx. 10%?
EN(H6DO)(diag)-73
ENGINE (DIAGNOSTICS)
Yes
Inspect the rele- Go to step 2.
vant DTC using
"List of Diagnostic
Trouble Code
(DTC)". <Ref. to
EN(H6DO)(diag)-
66, List of Diag-
nostic Trouble
Code (DTC).>
Check the follow- A temporary mal-
ing and repair or function.
replace if neces- Perform the follow-
sary. ing, and clean the
• Engine oil oil routing.
(amount, dirt) Replace the
• Oil pipe (clog) engine oil and idle
• Oil flow con- the engine for 5
trol solenoid minutes, and then
valve (clog or replace the oil filter
dirt of oil rout- and engine oil.
ing, setting of
spring, clog of
valve)
• Intake cam-
shaft (dirt, dam-
age of
camshaft)
• Timing chain
(matching of
timing mark)
No