Mazda 626 Station Wagon, Workshop Manual

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ON-BOARD DIAGNOSTIC
STEP INSPECTION
ACTION
5 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 a thick
cloth around and turn it slowly.
• Remove radiator cap.
• Implement procedure to bleed air from engine
coolant, then run engine at idle.
• Are there any small bubbles, which makes
engine coolant white at filling opening?
Note
• Large bubbles are normal since they are
remaining air coming out from engine
coolant passage.
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 Step 7.
No Go to next step.
6 INSPECT ENGINE COMPRESSION
• Inspect engine compression.
(See Section B)
• Is it okay?
Yes Go to next step.
No Implement engine overhaul for repairs, then go to next
step.
7 VERIFY TROUBLESHOOTING OF DTC P0134
or P0154 COMPLETED
• Make sure to reconnect all disconnected
connectors.
• Turn ignition key to ON (Engine OFF).
• Clear DTC from memory using NGS tester.
• Perform following procedures twice.
— Start engine.
— Access RPM and ECT PIDs using NGS.
— Verify that ECT PID is reading
above 80
" C {158 * F>.
— Increase engine speed above 1,500 rpm
(RPM PID reading) more than 73.5
seconds.
• Is same DTC present?
Yes Replace PCM, then go to next step.
No Go to next step.
8
VERIFY AFTER REPAIR PROCEDURE
• Perform “After Repair Procedure.”
(See F1 36 AFTER REPAIR PROCEDURE)
• Are there any DTCs present?
Yes Go to applicable DTC inspection.
(See F1-37 DTC TABLE)
No Troubleshooting completed.
F1-58