2002 MAZDA 6 service

F2–202
TROUBLESHOOTING
NO.14 POOR FUEL ECONOMYA6E408018881216
Diagnostic Procedure
14 POOR FUEL ECONOMY
DESCRIPTION•Fuel economy is unsatisfactory.
POSSIBLE
CAUSE•Incorrect idle speed
•A/C system improper operation
•Intake -air system clogging or restriction
•Engine cooling system malfunction
•Poor fuel quality
•Improper coolant level
•Erratic signal from CKP sensor
•Erratic signal from CMP sensor
•Fuel pressure sensor or related circuit malfunction
•ECT sensor or related circuit malfunction
•Boost sensor or related circuit malfunction
•Accelerator position sensor or related circuit malfunction
•Incorrect adjustment idle switch
•MAF/IAT sensor or related circuit malfunction
•IAT sensor No .2 or related circuit malfunction
•VSS or related circuit malfunction
•Turbocharger malfunction
•Charge air cooler malfunction
•Low engine compression
•Improper valve timing
•Exhaust system and/or catalyst converter clogging
•Incorrect fuel injection timing
•Fuel injector malfunction
•Supply pump malfunction
•Fuel leakage
•Fuel line clogging or restriction
•Fuel filter clogging or restriction
•Brake dragging
•EGR system malfunction
•Vacuum leakage
•Clutch slippage
•Variable boost control (VBC) system malfunction
•Coolant heater system malfunction
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:
•Fuel quality (e.g.: including water
contamination, winter/summer blend)
•Fuel line/fuel filter clogging and/or restriction
•Fuel line leakage
•Intake-air system restriction
•Exhaust system and/or catalyst converter
restriction
•Charge air cooler condition (restriction or
damaged)
•Vacuum leakage
Are all items okay?Yes Go to next step.
No Service as necessary.
Repeat Step 1.
2 Is brake system functioning properly? Yes Go to next step.
No Inspect for cause.

TROUBLESHOOTING
F2–203
F2
3 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.
4Note
•The following test should be performed on
the vehicles with A/C system. If the
following test cannot be performed due to
engine stalling, go to next step.
•Go to next step for the vehicle without A/C
system.
Connect pressure gauge to A/C line.
Turn blower and A/C switches on.
Is pressure within specifications?Yes Go to next step
NoA/C is always on:
Go to symptom troubleshooting “NO.24 A/C ALWAYS
ON OR A/C COMPRESSOR RUNS
CONTINUOUSLY”.
Other symptoms:
Inspect following:
•Refrigerant charging amount
•Cooling fan No.1 and/or cooling fan No.2
operation.
5 Access ECT PID.
Drive vehicle while monitoring PID.
Is PID within specification?Yes Go to next step.
No Inspect for coolant leakage, cooling fan No.1 and
cooling fan No.2 operations or thermostat operation.
6 Inspect idle speed.
(See F2–34 IDLE SPEED INSPECTION)
Is idle speed okay?Yes Go to next step.
No Go to symptom troubleshooting “NO.7 SLOW
RETURN TO IDLE”.
7 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.
8 Inspect adjustment of accelerator position
sensor and idle switch.
(See F2–72 ACCELERATOR POSITION
SENSOR INSPECTION)
(See F2–70 IDLE SWITCH INSPECTION)
Are accelerator position sensor and idle switch
adjusted correctly?Yes Go to next step.
No Adjust accelerator position sensor and idle switch
correctly.
(See F2–73 ACCELERATOR POSITION SENSOR
ADJUSTMENT)
(See F2–71 IDLE SWITCH ADJUSTMENT)
9 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.
10 Inspect fuel injector.
(See F2–56 FUEL INJECTOR INSPECTION)
Is fuel injector okay?Yes Go to next step.
No Repair or replace as necessary.
11 Perform turbocharger inspection.
(See F2–38 TURBOCHARGER INSPECTION)
Is turbocharger okay?Yes Go to next step.
No Replace turbocharger.
12 Inspect guide blade valve operation.
(See F2–229 ENGINE CONTROL SYSTEM
OPERATION INSPECTION)
Is there any problem?Yes Repair or replace as necessary.
No Go to next step.
13 Visually inspect CKP sensor and teeth of pulse
wheel.
Are CKP sensor and teeth of pulse wheel okay?Yes Go to next step.
No Replace malfunctioning parts. STEP INSPECTION RESULTS ACTION

F2–204
TROUBLESHOOTING
End Of Sie
14 Measure gap between CKP sensor and teeth of
pulse wheel.
Specification
1.5—2.5 mm {0.059—0.098 in}
Is gap within specification?Yes Go to next step.
No Adjust CKP sensor position.
15 Visually inspect CMP sensor and teeth of pulse
wheel.
Are CMP sensor and teeth of pulse wheel okay?Yes Inspect following PIDs:
(See F2–65 PCM INSPECTION)
•ECT
•IAT
•MAF
•MAP
•RPM
•VSS
If PID value is not as specified, repair or replace
malfunctioning parts.
If PID value is okay, go to next step.
No Replace malfunctioning parts.
16 Inspect timing belt for following:
•Chipping of gear teeth
•Low tension
•Breakage damage or cracks
Is timing belt okay?Yes Inspect following:
•Clutch slippage
•CKP sensor
•Boost sensor and related circuit
•Brake system for dragging
•Coolant heater system
•Glow system
If okay, remove and inspect supply pump.
No If timing is incorrect, adjust valve timing.
If timing belt is not okay, replace timing belt.
17 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

TROUBLESHOOTING
F2–205
F2
NO.15 EMISSION COMPLIANCEA6E408018881217
Diagnostic Procedure
15 EMISSION COMPLIANCE
DESCRIPTION•Fails emissions test.
POSSIBLE
CAUSE•Poor fuel quality
•Vacuum leakage
•Air leakage from intake-air system
•Intake-air system restriction or clogging
•Variable swirl control (VSC) system malfunction
•Variable boost control (VBC) system malfunction
•Intake shutter valve stuck close
•VSC valve stuck close
•Turbocharger malfunction
•Guide blade valve malfunction
•Charge air cooler malfunction
•Glow system malfunction
•EGR system malfunction
•EGR water cooler malfunction
•Low coolant temperature
•Engine overheating
•Inadequate fuel pressure
•Fuel pressure limiter malfunction (built-in common rail)
•Suction control valve inspection (built-in supply pump)
•ECT sensor or related circuit malfunction
•MAF/IAT sensor related circuit malfunction
•IAT sensor No.2 or related circuit malfunction
•Fuel pressure sensor or related circuit malfunction
•Incorrect adjustment accelerator position sensor and/or idle switch
•Accelerator position sensor or related circuit malfunction
•Idle switch or related circuit malfunction
•Fuel line rclogging or restriction
•Supply pump malfunction
•Fuel injector malfunction
•Incorrect fuel injection timing
•Incorrect idle speed
•Erratic signal from CKP sensor
•Erratic signal from CMP sensor
•Boost sensor or related circuit malfunction
•Neutral switch or related circuit malfunction
•VSS or related circuit malfunction
•Low engine compression
•Improper valve timing
•Base engine malfunction
•Exhaust system and/or catalyst converter restriction
•Catalyst converter malfunction
•IDM or related circuit malfunction
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 Is engine overheating? Yes Go to symptom troubleshooting “NO.17 COOLING
SYSTEM CONCERNS—OVERHEATING”.
No Go to next step.
2 Does engine run cold? Yes Go to symptom troubleshooting “NO.18 COOLING
SYSTEM CONCERNS—RUNS COLD”.
No Go to next step.

F2–206
TROUBLESHOOTING
3 Connect WDS or equivalent to DLC-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.
4 Inspect for following:
•Fuel quality (e.g.: including water
contamination, winter/summer blend)
•Fuel return line clogging and/or restriction
•Charge air cooler condition (restriction or
damaged)
•Intake-air system restriction
•Exhaust system and/or catalyst converter
restriction
•Vacuum leakage
Are all items okay?Yes Go to next step.
No Service as necessary.
Repeat Step 4.
5 Inspect adjustment of accelerator position
sensor and idle switch.
(See F2–72 ACCELERATOR POSITION
SENSOR INSPECTION)
(See F2–70 IDLE SWITCH INSPECTION)
Are accelerator position sensor and idle switch
adjusted correctly?Yes Go to next step.
No Adjust accelerator position sensor and idle switch
correctly.
(See F2–73 ACCELERATOR POSITION SENSOR
ADJUSTMENT)
(See F2–71 IDLE SWITCH ADJUSTMENT)
6 Inspect adjustment of neutral switch.
(See F2–69 NEUTRAL SWITCH INSPECTION)
Is neutral switch adjusted correctly?Yes Go to next step.
No Adjust neutral switch correctly.
7 Inspect intake shutter valve and VSC valve
operations.
(See F2–229 ENGINE CONTROL SYSTEM
OPERATION INSPECTION)
Is there any problem?Yes Repair or replace as necessary.
No Go to next step.
8 Inspect guide blade valve operation.
(See F2–229 ENGINE CONTROL SYSTEM
OPERATION INSPECTION)
Is there any problem?Yes Repair or replace as necessary.
No Go to next step.
9 Inspect hose bands between following parts:
•Turbocharger compressor housing and air
cleaner
•Turbocharger compressor housing and
charge air cooler
Are hose bands loose?Yes Retighten hose bands.
If concern is resolved, complete inspection.
If concern still exists, go to next step.
No Go to next step.
10 Inspect for improper operation, kinks, clogging or
disconnection on guide blade actuator.
(See F2–229 ENGINE CONTROL SYSTEM
OPERATION INSPECTION)
Is actuator okay?Yes Go to next step.
No Repair or replace as necessary.
If concern is resolved, complete inspection.
If concern still exists, turbocharger is okay.
Go to next step.
11 Remove parts necessary to inspect
turbocharger.
Do not remove turbocharger.
Inspect if turbocharger compressor wheel is
bent, damaged, or interfering with housing on
vehicle.
(See F2–38 TURBOCHARGER INSPECTION)
Is there any problem?Yes Replace turbocharger.
No Go to next step. STEP INSPECTION RESULTS ACTION

TROUBLESHOOTING
F2–207
F2
12 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.
13 Inspect turbocharger compressor wheel by
hand.
Does wheel turn easily and smoothly?Yes Go to next step.
No Replace turbocharger.
14 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.
15 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.
16 Is any engine oil found inside turbocharger
compressor hosing?Yes Wipe oil off of vehicle and install all removed parts in
Step 10. Then, go to next step.
No Turbocharger is okay.
Install all parts removed in Step10.
Then, go to next step.
17 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.
18 Inspect EGR water cooler for following:
•Coolant passage clogging/restriction
•Exhaust gas clogging/restriction
Is EGR water cooler okay?Yes Go to next step.
No Service as necessary.
19 Inspect glow system operation.
(See T–19 RELAY INSPECTION)
Is glow system operation normal?Yes Go to next step.
No Repair or replace malfunctioning part according to
glow system operation results.
20 Visually inspect CKP sensor and teeth of pulse
wheel.
Are CKP sensor and teeth of pulse wheel okay?Yes Go to next step.
No Replace malfunctioning parts.
21 Measure gap between CKP sensor and teeth of
pulse wheel.
Specification
1.5—2.5 mm {0.059—0.098 in}
Is gap within specification?Yes Go to next step.
No Adjust CKP sensor position.
22 Visually inspect CMP sensor and teeth of pulse
wheel.
Are CMP sensor and teeth of pulse wheel okay?Yes Inspect following PIDs:
(See F2–65 PCM INSPECTION)
•ECT
•IAT
•MAF
•MAP
•RPM
•VSS
If PID value is not as specified, repair or replace
malfunctioning parts.
If PID value is okay, go to next step.
No Replace malfunctioning parts.
23 Inspect fuel pressure sensor.
(See F2–79 FUEL PRESSURE SENSOR
INSPECTION)
Is fuel pressure okay?Yes Go to next step.
No Replace common rail.
24 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) STEP INSPECTION RESULTS ACTION

F2–208
TROUBLESHOOTING
End Of Sie
25 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.
26 Inspect fuel injector.
(See F2–56 FUEL INJECTOR INSPECTION)
Is fuel injector okay?Yes Go to next step.
No Repair or replace as necessary.
27 Inspect IDM.
(See F2–84 INJECTOR DRIVER MODULE
(IDM) INSPECTION)
Is IDM okay?Yes Go to next step.
No Repair or replace as necessary.
28 Inspect timing belt for followings:
•Chipping of gear teeth
•Low tension
•Breakage damage or cracks
Is timing belt okay?Yes Inspect following:
•ECT sensor
•Boost sensor
•MAF/IAT sensor
•Catalyst converter
If okay, remove and inspect supply pump and common
rail.
No If timing is incorrect, adjust valve timing.
If timing belt is not okay, replace timing belt.
29 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

TROUBLESHOOTING
F2–209
F2
NO.16 HIGH OIL CONSUMPTION/LEAKAGEA6E408018881218
Diagnostic Procedure
16 HIGH OIL CONSUMPTION/LEAKAGE
DESCRIPTION•Oil consumption is excessive.
POSSIBLE
CAUSE•Improper engine oil level
•Improper dipstick
•Improper engine oil viscosity
•Engine internal parts malfunction
•Oil leakage
•Turbocharger malfunction
STEP INSPECTION RESULTS ACTION
1 Verify following:
•Proper dipstick
•Proper engine viscosity
•Engine oil level
Are all items okay?Yes Go to next step.
No Service as necessary.
Repeat Step 1.
2 Remove to necessary to inspect turbocharger.
Note
•Do not remove turbocharger.
Inspect if turbocharger compressor wheel is
bent, damaged, or interfering with housing on
vehicle.
Is there any problem?Yes Replace turbocharger.
No Go to next step.
3 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.
4 Turn turbocharger compressor wheel by hand.
Does wheel turn easily and smoothly?Yes Go to next step.
No Replace turbocharger.
5 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.
6 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.
7 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.
8 Is any engine oil found around oil pipes attached
on turbocharger center housing?Yes If oil leaks from damaged pipe, replace oil pipe.
Then, go to next step.
No Go to next step.
9 Is any engine oil found inside air intake pipes or
hoses?Yes Wipe engine oil off.
No Turbocharger is okay.
Install all parts removed in Step 2.
Then go to next step.
10 Is engine compression correct?
(See B2–8 COMPRESSION INSPECTION)Yes Inspect oil leakage from outside of engine.
No Inspect for following:
•Damaged valve seat
•Worn valve stem and valve guide
•Worn or stuck piston ring
•Worn piston, piston ring or cylinder
Service as necessary.
11 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)