2002 MAZDA 6 service

F2–210
TROUBLESHOOTING
End Of SieNO.17 COOLING SYSTEM CONCERNS-OVERHEATINGA6E408018881219
Diagnostic Procedure
17
COOLING SYSTEM CONCERNS-OVERHEATING
DESCRIPTION•Engine runs at higher than normal temperature/overheats.
POSSIBLE
CAUSE•Cooling fan No.2 malfunction
•Cooling fan No.1 malfunction
•Low drive belt tension
•Drive belt damage
•Improper coolant level
•Thermostat malfunction
•Radiator clogging
•Improper water/anti-freeze mixture
•Improper or damaged radiator cap
•Radiator hose damage
•Coolant leakage (engine internal, turbocharger, external)
•A/C system malfunction
•EGR system malfunction
•Coolant heater system malfunction
STEP INSPECTION RESULTS ACTION
1 Inspect following:
•Engine coolant level
•Coolant leakage (around heater unit in
passenger compartment, coolant hoses and/
or radiator, and around coolant heater unit.)
•Water and anti-freeze mixture
•Radiator condition
•Collapsed or restricted radiator hoses
•Radiator pressure cap
•Drive belt tension
•Drive belt
•Fan rotational direction
Are all items okay?Yes Go to next step.
No Service as necessary.
Repeat Step 1.
2 Perform self-test function using WDS or
equivalent.
Turn engine switch to ON.
Retrieve any DTC.
Is DTC displayed?YesDTC is displayed:
Go to appropriate DTC test.
Communication error message is displayed:
Inspect for following:
•Open circuit between PCM control relay and PCM
terminal 53 or 79
•Open circuit PCM control relay and PCM terminal
69
•PCM control relay stuck open
•Open or poor GND circuit (PCM terminal 65, 85,
103 or 104)
•Poor connection vehicle body GND
NoNo DTC is displayed:
Go to next step.

TROUBLESHOOTING
F2–211
F2
End Of Sie
3Note
•The following test should be performed on
the vehicles with A/C system. Go to next
step for vehicles without A/C system
Start engine and run it at idle speed.
Turn A/C switch off.
Does A/C compressor disengaged?Yes Go to next step.
No Go to symptom troubleshooting “NO.24 A/C ALWAYS
ON OR A/C COMPRESSOR RUNS
CONTINUOUSLY”.
4 Start engine and run it at idle speed.
Turn A/C switch on if equipped.
Do cooling fan No.1 and/or cooling fan No.2
operate?Yes Go to next step.
NoCooling fan No.1 does not operate:
Inspect for following:
•Cooling fan relay No.1 is stuck open
•Cooling fan motor No.1 malfunction
•Cooling fan motor No.1 GND open
•Open circuit between cooling fan motor No.1 and
relay
•Open circuit between cooling fan relay No.1 and
PCM terminal 102
•Open battery power circuit of cooling fan relay
No.1
Cooling fan No.2 does not operate:
Inspect for following:
•Cooling fan relay No.2 is stuck open
•Cooling fan motor No.2 malfunction
•Cooling fan motor No.2 GND open
•Open circuit between Cooling fan motor No.2 and
relay
•Open circuit between Cooling fan relay No.2 and
PCM terminal 76
•Open battery power circuit of Cooling fan relay
No.2
5 Is drive belt okay? Yes Go to next step.
No Replace drive belt.
6 Perform EGR system inspection.
Is EGR system okay?Yes Go to next step.
No Repair or replace malfunctioning part according to
EGR system operation results.
7 Perform coolant heater system inspection.
(See E–10 THERMOSTAT INSPECTION)
Is coolant heater system okay?Yes Go to next step.
No Repair or replace malfunctioning part according to
coolant heater system operation results.
8 Cool down engine.
Remove thermostat and inspect operation.
Is thermostat okay?Yes Thermostat is okay.
Inspect cylinder block for leakage or blockage.
No Replace thermostat.
9 Verify test results.
•If okay, return to diagnostic index to service any additional symptoms.
•If malfunction remains, replace PCM. (See F2–64 PCM REMOVAL/INSTALLATION) STEP INSPECTION RESULTS ACTION

F2–212
TROUBLESHOOTING
NO.18 COOLING SYSTEM CONCERNS-RUNS COLDA6E408018881220
Diagnostic Procedure
End Of Sie
18 COOLING SYSTEM CONCERNS-RUNS COLD
DESCRIPTION•Engine takes excessive period for reaching normal operating temperature.
POSSIBLE
CAUSE•Thermostat malfunction
•Cooling fan No.2 system malfunction
•Cooling fan No.1 system malfunction
•Coolant heater system malfunction
STEP INSPECTION RESULTS ACTION
1 Is customer complaint “Lack of passenger
compartment heat”?Yes Inspect A/C heater system.
No Go to next step.
2 Does engine speed continue at fast idle? Yes Go to symptom troubleshooting “NO.7 SLOW
RETURN TO IDLE”.
No Go to next step.
3 Connect WDS or equivalent to DLC-2.
Access ECT PID.
Inspect for both ECT PID and temperature
gauge on instrument cluster readings.
Is ECT PID same as temperature gauge
reading?Yes Go to next step.
No If temperature gauge on instrument cluster indicates
normal range but ECT PID is not same as temperature
gauge reading, inspect ECT sensor.
If temperature gauge on instrument cluster indicates
cold range but ECT PID is normal, inspect
temperature gauge and heat gauge unit.
4 Remove thermostat and inspect operation.
(See E–9 THERMOSTAT REMOVAL/
INSTALLATION)
(See E–10 THERMOSTAT INSPECTION)
Is thermostat okay?Yes Go to next step.
No Replace thermostat.
5 Inspect cooling fan No.1 and cooling fan No.2
operations.
If both or either fan operate normally, inspect for
following:
•Cooling fan relay No.2 is stuck closed
•Short to GND between cooling fan relay No.2
and PCM terminal 76
•Circuit between cooling fan relay No.2 and
fan motor short to battery supply line
•Cooling fan relay No.1 is stuck closed
•Short to GND between cooling fan relay No.1
and PCM terminal 102
•Circuit between cooling fan relay No.1 and
fan motor short to battery supply line
•Short to GND between A/C switch and PCM
terminal 84
Are all circuits okay?Yes Perform coolant heater system inspection.
Repair or replace malfunctioning part according to
coolant heater system operation results.
No Repair or replace as necessary.
6 Verify test results.
•If okay, return to diagnostic index to service any additional symptoms.
•If malfunction remains, replace PCM. (See F2–64 PCM REMOVAL/INSTALLATION)

TROUBLESHOOTING
F2–213
F2
NO.19 EXCESSIVE BLACK SMOKEA6E408018881221
Diagnostic Procedure
19 EXCESSIVE BLACK SMOKE
DESCRIPTION•Excessive black smoke is observed in exhaust gas.
POSSIBLE
CAUSE•Intake-air system clogging or restriction
•Air leakage from Intake-air system
•Incorrect fuel injection timing
•Erratic signal from CKP sensor
•Fuel pressure sensor or related circuit malfunction
•Boost sensor or related circuit malfunction
•IAT sensor No.2 or related circuit malfunction
•Fuel injector malfunction
•Excessive fuel pressure
•Suction control valve malfunction (built-in supply pump)
•Fuel line clogging or restriction
•Fuel pressure limiter malfunction (built-in common rail)
•Low engine compression
•Improper valve timing
•Base engine malfunction
•EGR system malfunction
•Variable boost control (VBC) system malfunction
•Vacuum leakage
•Turbocharger malfunction
•Charge air cooler malfunction
•Intake shutter valve malfunction
•Variable swirl control (VSC) system malfunction
•VSC valve malfunction
•IDM or related circuit malfunction
•Exhaust system and/or catalyst converter restriction or clogging
Warning
The following troubleshooting flow chart contains the fuel system diagnosis and repair
procedures. Read the following warnings before performing the fuel system services:
•Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep
sparks and flames away from fuel.
•Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death
and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE
REPAIR PROCEDURE” and “AFTER REPAIR PROCEDURE” described in this manual.
STEP INSPECTION RESULTS ACTION
1 Inspect for following:
•Intake-air system clogging or restriction
•Exhaust system and/or catalyst converter
restriction or clogging
•Charge air cooler condition (restriction or
damaged)
Are all items okay?Yes Go to next step.
No Service as necessary.
Repeat Step 1.
2 Perform self-test function using WDS or
equivalent.
Turn engine switch to ON.
Retrieve any DTC.
Is DTC displayed?YesDTC is displayed:
Go to appropriate DTC test.
Communication error message is displayed:
Inspect for following:
•Open circuit between PCM control relay and PCM
terminal 53 or 79
•Open circuit PCM control relay and PCM terminal
69
•PCM control relay stuck open
•Open or poor GND circuit (PCM terminal 65, 85,
103 or 104)
•Poor connection vehicle body GND
NoNo DTC is displayed:
Go to next step.
3 Does any other symptom exist? Yes Go to appropriate flowchart.
No Go to next step.
4 Inspect for air cleaner element for clogging.
Is air cleaner element okay?Yes Go to next step.
No Repair or replace air cleaner element.

TROUBLESHOOTING
F2–215
F2
End Of Sie
15 Inspect if turbocharger compressor wheel
locknut is loose or has fallen down inside
turbocharger.
Is there any problem?Yes Replace turbocharger.
No Go to next step.
16 Inspect if turbocharger compressor wheel by
hand.
Does wheel turn easily and smoothly?Yes Go to next step.
No Replace turbocharger.
17 Inspect if turbocharger turbine wheel is
damaged, cracked or interfering with housing on
vehicle.
Note
•Inspect all fins on each turbine wheel.
Is there any problem?Yes Replace turbocharger.
No Go to next step.
18 Is any engine oil found inside turbocharger
compressor housing?Yes Wipe oil off of vehicle and install all removed parts in
Step 15. Then, go to next step.
No Turbocharger is okay.
Install all parts removed is Step 15. Then, go to next
step.
19 Inspect suction control valve.
(See F2–54 SUCTION CONTROL VALVE
INSPECTION)
Is suction control valve okay?Yes Go to next step.
No Repair supply pump.
(See F2–54 SUPPLY PUMP INSPECTION)
20 Is engine compression correct?
(See B2–8 COMPRESSION INSPECTION)Yes Go to next step.
No Inspect for following:
•Damaged valve seat
•Worn valve stem and valve guide
•Worn or stuck piston ring
•Worn piston, piston ring or cylinder
•Improper valve timing
Service as necessary.
21 Inspect IDM.
(See F2–84 INJECTOR DRIVER MODULE
(IDM) INSPECTION)
Is IDM okay?Yes Go to next step.
No Repair or replace as necessary.
22 Inspect fuel injector.
(See F2–56 FUEL INJECTOR INSPECTION)
Is fuel injector okay?Yes Inspect following:
•Boost sensor
•Fuel pressure limiter (built-in common rail)
•Fuel pressure sensor
•Fuel return line restriction or clogging
Service as necessary.
No Repair or replace as necessary.
23 Verify test results.
•If okay, return to diagnostic index to service any additional symptoms.
•If malfunction remains, replace PCM. (See F2–64 PCM REMOVAL/INSTALLATION) STEP INSPECTION RESULTS ACTION

F2–216
TROUBLESHOOTING
NO.20 FUEL ODOR (IN ENGINE COMPARTMENT)A6E408018881222
Diagnostic Procedure
End Of Sie
20 FUEL ODOR (IN ENGINE COMPARTMENT)
DESCRIPTION•Fuel smell or visible leakage.
POSSIBLE
CAUSE•Excessive fuel pressure
•Suction control valve malfunction (built-in supply pump)
•Fuel pressure limiter malfunction (built-in common rail)
•Fuel pressure sensor or related circuit malfunction
•Fuel leakage
Warning
The following troubleshooting flow chart contains the fuel system diagnosis and repair
procedures. Read the following warnings before performing the fuel system services:
•Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep
sparks and flames away from fuel.
•Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death
and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE
REPAIR PROCEDURE” and “AFTER REPAIR PROCEDURE” described in this manual.
STEP INSPECTION RESULTS ACTION
1 Visually inspect fuel leakage at fuel injector and
fuel line.
Is there any fuel leakage?Yes Service as necessary.
No Go to next step.
2 Visually inspect for damaged or cracked fuel
filter.
Is fuel filter okay?Yes Go to next step.
No Replace fuel filter.
3 Inspect fuel pressure sensor.
(See F2–79 FUEL PRESSURE SENSOR
INSPECTION)
Is fuel pressure okay?Yes Go to next step.
No Repair or replace as necessary.
4 Inspect suction control valve.
(See F2–54 SUCTION CONTROL VALVE
INSPECTION)
Is suction control valve okay?Yes Go to next step.
No Repair supply pump.
(See F2–54 SUPPLY PUMP INSPECTION)
5 Perform self-test function using WDS or
equivalent.
Turn engine switch to ON.
Retrieve any DTC.
Is DTC displayed?YesDTC is displayed:
Go to appropriate DTC test.
Communication error message is displayed:
Inspect for following:
•Open circuit between PCM control relay and PCM
terminal 53 or 79
•Open circuit PCM control relay and PCM terminal
69
•PCM control relay stuck open
•Open or poor GND circuit (PCM terminal 65, 85,
103 or 104)
•Poor connection vehicle body GND
NoNo DTC is displayed:
Remove and inspect common rail.
6 Verify test results.
•If okay, return to diagnostic index to service any additional symptoms.
•If malfunction remains, replace PCM. (See F2–64 PCM REMOVAL/INSTALLATION)

TROUBLESHOOTING
F2–217
F2
NO.21 ENGINE NOISEA6E408018881223
Diagnostic Procedure
21 ENGINE NOISE
DESCRIPTION•Engine noise under hood.
POSSIBLE
CAUSE•Engine internal damage
•Timing belt displacement
•Fuel injector malfunction
•Loose attaching bolts or worn parts
•Improper drive belt tension
•Air leakage from intake-air system
•Incorrect injection timing
•Erratic signal from CKP sensor
•Erratic signal from CMP sensor
•Fuel pressure sensor or related circuit malfunction
•Boost sensor or related circuit malfunction
•Accelerator position sensor or related circuit malfunction
•MAF/IAT sensor or related circuit malfunction
•ECT sensor or related circuit malfunction
•EGR system or malfunction
•IAT sensor No.2 or related circuit malfunction
•Vacuum leakage
•Suction control valve malfunction (built-in supply pump)
•Air leakage from intake-air system
•Air in power steering fluid line
•Turbocharger operating noise
•Solenoid valve operating noise
Warning
The following troubleshooting flow chart contains the fuel system diagnosis and repair
procedures. Read the following warnings before performing the fuel system services:
•Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep
sparks and flames away from fuel.
•Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injury or death
and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE
REPAIR PROCEDURE” and “AFTER REPAIR PROCEDURE” described in this manual.
Note
•PCM checks fuel injection amount during a set interval while idling, and automatically corrects it to
maintain engine efficiency. It is normal that engine noise and vibration might be a little louder during
this process.
STEP INSPECTION RESULTS ACTION
1 Is squeal, click or chirp sound present? Yes Inspect engine oil level, solenoid valves installation or
drive belt.
No Go to next step.
2 Is rumble or grind sound present? Yes Inspect drive belt tension or power steering system
fluid level.
If okay, perform power steering fluid line air bleed.
No Go to next step.
3 Is rattle sound present? Yes Inspect location of rattle for loose parts.
No Go to next step.
4 Is hiss sound present? Yes Inspect for vacuum leakage and intake-air system
leakage.
No Go to next step.
5 Is rap or roar sound present? Yes Inspect exhaust system or loose parts.
No Go to next step.

TROUBLESHOOTING
F2–219
F2
End Of Sie
14 Inspect if turbocharger compressor wheel
locknut is loose or has fallen down inside
turbocharger.
Is there any problem?Yes Replace turbocharger.
No Go to next step.
15 Turn turbocharger compressor wheel by hand.
Does wheel turn easily and smoothly?Yes Go to next step.
No Replace turbocharger.
16 Inspect if turbocharger turbine wheel is
damaged, cracked or interfering with housing on
vehicle.
Note
•Inspect all fins on each turbine wheel.
Is there any problem?Yes Replace turbocharger.
No Go to next step.
17 Is any engine oil found inside turbocharger
turbine housing?YesExcessive amount of oil is found:
Replace turbocharger.
Small amount of oil is found:
Wipe oil off of vehicle, then go to next step.
No Go to next step.
18 Is any engine oil found inside turbocharger
compressor housing?Yes Wipe oil off of vehicle, then go to next step.
No Go to next step.
19 Is any exhaust gas leakage found around
location where turbocharger is attached to
exhaust manifold?Yes Remove turbocharger.
Inspect for cracks on center housing inlet surface.
If cracks are found, replace turbocharger.
No Go to next step.
20 Are any center housing and turbine housing
attaching bolts loose?Yes Retighten loose bolts.
If a bolt is found to be missing, attach appropriate new
bolts.
No Turbocharger is okay.
Install all parts removed in Step 13.
Go to next step.
21 Inspect suction control valve.
(See F2–54 SUCTION CONTROL VALVE
INSPECTION)
Is suction control valve okay?Yes Go to next step.
No Repair supply pump.
(See F2–54 SUPPLY PUMP INSPECTION)
22 Inspect fuel injector and fuel injector gasket.
(See F2–56 FUEL INJECTOR INSPECTION)
Is fuel injector okay?Yes Inspect for following:
•Metal flow
•Bent connecting rod
•Damaged valve seat
•Incorrect valve clearance
No Repair or replace as necessary.
23 Verify test results.
•If okay, return to diagnostic index to service any additional symptoms.
•If malfunction remains, replace PCM. (See F2–64 PCM REMOVAL/INSTALLATION) STEP INSPECTION RESULTS ACTION