Mazda 6 2002 Workshop Manual page 221

STEP
21 INSPECT SEALING OF ENGINE COOLANT
PASSAGE
Warning
• • • • Removing radiator cap when radiator is
hot is dangerous. Scalding coolant and
steam may shoot out and cause serious
injury.
• • • • When removing radiator cap, wrap thick
cloth around and turn it slowly.
• Remove radiator cap.
• Implement procedure to bleed air from engine
coolant, then run engine at idle.
• Is there any small bubble which makes engine
coolant white at filling opening?
Note
• Large bubbles are normal since they are
remaining air coming out from engine
coolant passage.
22 VERIFY TROUBLESHOOTING OF MISFIRE DTC
COMPLETED
• Make sure to reconnect all disconnected
connectors.
• Turn ignition key to ON (Engine OFF).
• Clear DTC from memory using WDS or
equivalent.
• Run PCM adaptive memory procedure drive
mode.
(See F–64 OBD DRIVE
• Is PENDING CODE the same as DTC
present?
23 VERIFY AFTER REPAIR PROCEDURE
• Perform “After Repair Procedure”.
(See F–66 AFTER REPAIR
• Is there any DTC present?
End Of Sie
DTC P0301, P0302, P0303, P0304
DTC P0301 Cylinder No.1 misfire detection
DTC P0302 Cylinder No.2 misfire detection
DTC P0303 Cylinder No.3 misfire detection
DTC P0304 Cylinder No.4 misfire detection
• PCM monitors CKP sensor input signal interval time. PCM calculates the change of interval time for each
cylinder. If the change of interval time eceeds the preprogrammed criteria, PCM detects a misfire in the
corresponding cylinder. While the engine is running, PCM counts number of misfires that occurred at 200
crankshaft revolutions and 1,000 crankshaft revolutions and calculates misfire ratio for each
crankshaft revolution. If the ratio eceeds the preprogrammed criteria, PCM determines that a misfire,
which can damage catalytic converter or affect emission performance, has occurred.
Diagnostic support note
DETECTION
• This is a continuous monitor (MISFIRE).
CONDITION
• MIL illuminates if PCM detects the misfire which affects emission performance in two consecutive drive
cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
• MIL flashes if PCM detects the misfire which can damage the catalytic converter during first drive cycle.
Therefore, PENDING CODE is not available while MIL flashes.
• PENDING CODE is available if PCM detects the misfire which affects emission performance during first
drive cycle.
• FREEZE FRAME DATA is available.
• DTC is stored in the PCM memory.
• Spark plug malfunction
• High-tension lead malfunction
• Fuel injector malfunction
POSSIBLE
• Air suction in intake air system (between dynamic chamber and cylinder head)
CAUSE
• Inadequate engine compression due to engine internal malfunction
• Related connector or terminal malfunction
• Related wiring harness malfunction
F–124
ON-BOARD DIAGNOSTIC
INSPECTION
MODE.)
PROCEDURE.)
Yes Air gets in from poor sealing on head gasket or other areas
between combustion chamber and engine coolant
passage. Repair or replace faulty parts, then go to net
step.
No Go to net step.
Yes Replace PCM, then go to net step.
(See F–43 PCM REMOVAL/INSTALLATION.)
No Go to net step.
Yes Go to applicable DTC troubleshooting.
(See F–67 DTC TABLE.)
No Troubleshooting completed.
ACTION
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