Mazda 6 2002, Workshop Manual

Page: 345 / 1248

TROUBLESHOOTING
F–215
F
NO.17 COOLING SYSTEM CONCERNS-OVERHEATING
A6E398018881W19
Diagnostic procedure
17 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
•
A/C system operation is improper
•
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
•
Cooling fan is inoperative.
•
Coolant overflow system malfunction
•
Improper tension of drive belt
•
Drive belt damage
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 WDS or equivalent to DLC-2.
Retrieve any continuous memory, KOEO and
KOER DTCs.
Are there any DTCs displayed? Yes DTC is displayed:
Go to appropriate DTC test.
No No DTC is displayed:
Go to next step.
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 for following and repair or replace as
necessary:
•
Refrigerant charging amount
•
Open circuit between A/C relay and PCM terminal
4O
•
Seized A/C magnetic clutch
•
A/C magnetic clutch malfunction
If all items are okay, go to next step.
4 Connect WDS or equivalent to DLC-2.
Access ACSW PID.
Start engine and run it at idle speed.
Turn A/C switch on.
Does ACSW PID read ON? Yes Go to next step.
No Inspect following:
•
Refrigerant pressure switch operation
•
A/C switch is stuck open.
•
Open or short circuit between refrigerant pressure
switch and PCM terminal 1AC
•
Open circuit of blower motor fan switch and resistor
(if blower motor does not operate)
•
Evaporator temperature sensor and A/C amplifier
5 Inspect cooling fan control system operation.
(See
F–234 Cooling Fan Control System
Inspection .)
Does cooling fan control system work properly?
Yes Go to next step.
No Repair or replace malfunctioning parts.
6 Is drive belt okay? Yes Go to next step.
No Replace drive belt.
7 Is there any leakage around heater unit in
passenger compartment? Yes Inspect and service heater for leakage.
No Go to next step.
8 Is there any leakage at coolant hoses and/or
radiator? Yes Replace malfunctioning part.
No Go to next step.