Mazda 626 - Instrument Cluster

TROUBLESHOOTING
NO.16 COOLING SYSTEM CONCERNS—OVERHEATING
16
Cooling system concerns overheating
DESCRIPTION
Engine runs at higher than normal temperature/Overheats.
POSSIBLE
CAUSE
Improper coolant level
Blown fuses
Coolant leakage
Excessive A/C system pressure
Improper water/anti-freeze mixture
Fans reverse rotation
Poor radiator condition
Thermostat malfunction
Radiator hoses damage
Condenser fan is inoperative.
Improper or damaged radiator cap
Main cooling fan is inoperative.
Coolant overflow system malfunction
Improper tension of drive belt
Drive belt damage
_______________
Diagnostic Procedure
STEP INSPECTION
RESULTS ACTION
1
Inspect following:
• Engine coolant level
• Coolant leakage
• Water and anti-freeze mixture
• Radiator condition
• Collapsed or restricted radiator hoses
• Radiator pressure cap
• Overflow system
• Fan rotational direction
• Fuses
Are all items okay?
Yes Go to next step.
No Service as necessary.
Repeat Step 1.
2 Connect NGS tester to DLC.
Turn ignition switch on.
Retrieve any DTC.
Is any DTC displayed?
Yes No DTC is displayed:
Go to next step.
No DTC is displayed:
Go to appropriate DTC test.
3
Start engine and run it at idle speed.
Turn A/C switch on.
Does A/C compressor engage?
Yes
Go to Step 5.
No Inspect following and repair or replace as
necessary:
• Refrigerant charging amount
• Open circuit between A/C relay and PCM
terminal 69 (for GF4A-EL models) or 96
(except for GF4A-EL models)
• Seized A/C magnetic clutch
• A/C magnetic clutch malfunction
If all items are okay, go to next step.
4
Connect NGS tester to DLC.
Access AC S/W or ACCS PID on NGS tester.
Start engine and run it at idle speed.
Turn A/C switch on.
Does AC S/W or ACCS PID read on?
Yes
Go to next step.
No
Inspect for following:
• Refrigerant pressure switch operation
• A/C switch is stuck open.
• Open or short circuit between refrigerant
pressure switch and PCM terminal 41
• Open circuit of blower motor fan switch and
resistor (if blower motor does not operate)
• Evaporator temperature sensor and A/C
amplifier
F1-133