Dtc P0012 - Mazda 2002 6 Workshop Manual

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DTC P0012

DTC P0012
CMP - Timing over-retarded
• Actual valve timing is over-retarded by 5 deg. from target valve timing for 5 s when the OCV system control
is within feed-back range.
Diagnostic support note
• This is a continuous monitor (CCM).
DETECTION
• MIL illuminates if PCM detects the above malfunction condition during first drive cycles.
CONDITION
• PENDING CODE is available if PCM detects the above malfunction condition.
• FREEZE FRAME DATA is available.
• DTC is stored in PCM memory.
• OCV (oil control valve) malfunction
• Low engine oil pressure
• Spool valve in OCV (oil control valve) is stuck in retard position.
• Vriable valve timing actuator is stuck in retard position.
• Following oil runners are clogged or have leakage.
POSSIBLE
Oil runners
CAUSE
• Between oil pressure switch and OCV (oil control valve)
• Between OCV (oil control valve) and variable valve timing actuator
• In variable valve timing actuator
• Loose timing belt or improper valve timing due to timing belt slippage
• PCM malfunction
Diagnostic procedure
STEP
1
PERFORM DTC CONFIRMATION PROCEDURE
• Perform DTC CONFIRMATION PROCEDURE.
(See
F–66 DTC CONFIRMATION
PROCEDURE.)
• Is same DTC present?
2
VERIFY RELATED PENDING CODE OR
STORED DTCS
• Is DTC P0010 present?
3
VERIFY ENGINE OIL PRESSURE
• Start engine.
• Does oil pressure warning light illuminate?
4
VERIFY TIMING BELT INSTALLATION
• Stop engine.
• Remove timing belt cover.
• Is camshaft timing mark at correct point?
(See
B–10 TIMING CHAIN REMOVAL/
INSTALLATION.)
5
INSPECT OCV FOR MALFUNCTION
• Stop engine.
• Remove OCV.
• Inspect position of spool valve in OCV.
• Is spool valve located at valve retard position?
6
INSPECT ENGINE OIL RUNNER
• Inspect following engine oil runners for
clogging or leakage.
— Beetween oil pressure switch and OCV
— Between OCV and variable valve timing
actuator
— In variable valve timing actuator
• Is there any clogging or leakage?
ON-BOARD DIAGNOSTIC
INSPECTION
Yes Go to next step.
No
Intermittent concern exists. Go to INTERMITTENT
CONCERN TROUBLESHOOTING procedure.
(See
F–227 INTERMITTENT CONCERN
TROUBLESHOOTING.)
Yes Go to DTC P0010 troubleshooting procedure.
(See
F–70 DTC
P0010)
No
Go to next step.
Yes Inspect engine oil pressure.
(See
D–3 OIL PRESSURE
No
Go to next step.
Yes Go to next step.
No
Reinstall timing belt, then go to Step 7.
Yes VARIABLE VALVE TIMING MECHANISM IS NORMAL
Note
• This DTC detected by intermittent concern.
• Intermittent concern might be removed by cleaning
mode of variable valve timing control function.
Go to next step.
No
Replace OCV, then go to Step 7.
Yes Repair or replace suspected runner, then go to next step.
No
VARIABLE VALVE TIMING MECHANISM IS NORMAL
Note
• This DTC is detected by intermittent concern.
• Intermittent concern might be removed by cleaning
mode of variable valve timing control function.
Go to next step.
A6E397001084W03
ACTION
INSPECTION)
F–73
F

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