2002 MAZDA 6 Workshop Manual Suplement

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.

F2–218
TROUBLESHOOTING
6 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 appropriate DTC test.
7 Access ECT PID.
Inspect ECT PID while warming up engine.
Is PID value correct?Yes Go to next step.
No Inspect ECT sensor and related wiring harnesses.
8 Access IAT PID.
Inspect IAT PID while running engine.
Is PID value correct?Yes Go to next step.
No Inspect IAT sensor and related wiring harnesses.
9 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.
10 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.
11 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
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.
12 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.
13 Remove parts 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. STEP INSPECTION RESULTS ACTION

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

F2–220
TROUBLESHOOTING
NO.22 VIBRATION CONCERNS (ENGINE)A6E408018881224
Diagnostic Procedure
22 VIBRATION CONCERNS (ENGINE)
DESCRIPTION•Vibration from under hood or driveline.
POSSIBLE
CAUSE•Loose attaching bolts or worn parts
•Cooling fan No.1 or cooling fan No.2 seat are improper
•Engine or transaxle mounts are improperly installed
•Components malfunction such as worn parts
•Erratic signal from CMP sensor
•ECT sensor or related circuit malfunction
•Accelerator position sensor or related circuit malfunction
•MAF/IAT sensor or related circuit malfunction
•Idle switch or related circuit malfunction
•Incorrect adjustment of accelerator position sensor and/or idle switch
•Fuel injector malfunction
•Vacuum leakage
•Improper tension or damaged drive belts
•Improper balance of wheels or tires
•Driveline malfunction
•Suspension 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 following components for loose attaching
bolts or worn parts:
•Cooling fan No.1
•Cooling fan No.2
•Cooling fan No.1 and cooling fan No.2 seat
•Drive belt and pulley
•Engine mounts
•Exhaust system
Are all items okay?Yes Go to next step.
No Readjust or retighten engine mount installation
position.
Service as necessary for other parts.
2 Inspect vacuum leakage.
Are vacuum hoses okay?Yes Go to next step.
No Service as necessary.
Repeat Step 2.

TROUBLESHOOTING
F2–221
F2
End Of Sie
3 Connect WDS or equivalent to DLC-2.
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 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 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)
5 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.
6 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
•RPM
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.
7 Inspect fuel injector.
(See F2–56 FUEL INJECTOR INSPECTION)
Is fuel injector okay?Yes Inspect following systems:
•Wheels
•Transaxle and mounts
•Driveline
•Suspension
Service as necessary.
No Repair or replace as necessary.
8 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

F2–222
TROUBLESHOOTING
NO.23 A/C DOES NOT WORK SUFFICIENTLYA6E408018881225
Diagnostic Procedure
End Of Sie
23 A/C DOES NOT WORK SUFFICIENTLY
DESCRIPTION•A/C compressor magnetic clutch does not engage when A/C switch is turned on.
POSSIBLE
CAUSE•Improper refrigerant charge amount
•Open A/C switch magnetic clutch
•Open circuit between A/C relay and A/C magnetic clutch
•Poor GND of A/C magnetic clutch
•Improper A/C magnetic clutch clearance
•Refrigerant pressure switch is stuck open
•A/C relay is stuck open
•Improper A/C cut-off control
•Open circuit between A/C switch and PCM through both refrigerant pressure switch and A/C amplifier
STEP INSPECTION RESULTS ACTION
1 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
YesNo DTC is displayed:
Go to appropriate DTC test.
2 Disconnect A/C compressor connector.
Start engine and turn A/C switch to ON.
Is there correct voltage at terminal of A/C
compressor magnetic clutch connector?
Specification
More than 10.5 VYes Inspect for GND condition of magnetic clutch on A/C
compressor.
If GND condition is okay, inspect magnetic clutch coil
for open circuit.
No Go to next step.
3 Disconnect refrigerant pressure switch
connector.
Connect jumper wire between terminals of
refrigerant pressure switch connector.
Turn engine switch to ON.
Turn A/C switch on and set blower fan at any
speed.
Measure PCM terminal 84 voltage.
Is voltage below 1.0 V?Yes Inspect refrigerant pressure switch operation.
If switch is okay, go to next step.
No Inspect for following:
•A/C switch is stuck open
•Open circuit between refrigerant pressure switch
and PCM terminal 84
•Open circuit of blower motor fan switch and
resistor (if blower motor does not operate)
•Evaporator temperature sensor and A/C amplifier
4 Inspect A/C cut-off operation.
Does A/C cut-off work properly?Yes Go to next step.
No Repair or replace malfunctioning part according to A/C
cut-off system inspection results.
5 Remove jumper wire from switch connector.
Reconnect connector to refrigerant pressure
switch.
Start engine and turn A/C switch on.
Does fan operate?Yes Inspect for stuck open A/C relay.
Replace if necessary.
No Inspect following and repair or replace as necessary:
•Refrigerant charging amount
•Seized A/C compressor
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
F2–223
F2
NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLYA6E408018881226
Diagnostic Procedure
End Of Sie
24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
DESCRIPTION•A/C compressor magnetic clutch does not disengage.
POSSIBLE
CAUSE•A/C compressor magnetic clutch stuck engagement
•A/C relay is stuck closed
•Improper A/C compressor magnetic clutch clearance
•Short to GND circuit between A/C switch and PCM
•Short to GND circuit between A/C relay and PCM
•A/C relay to magnetic clutch circuit shorts to battery power
STEP INSPECTION RESULTS ACTION
1 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 appropriate DTC test.
2 Start engine and run it at idle.
Turn A/C switch on.
Remove A/C relay.
Does A/C magnetic clutch disengage?Yes Inspect for following:
•A/C relay is stuck closed
•Short to GND circuit between A/C relay and PCM
terminal 73
If both items are okay, go to next step.
No Inspect if circuit between A/C relay and magnetic
clutch shorts to battery power circuit.
If circuit is okay, inspect magnetic clutch stuck
engagement or clearance.
3 Start engine and turn A/C switch on.
Measure PCM terminal 84 voltage while
disconnecting refrigerant pressure switch
connector.
Note
•PCM terminal 84 voltage should read B+
when disconnecting connector. If PCM
terminal 84 voltage reading remains
below 1.0 V, short to GND circuit may be
present.
Is voltage B+?Yes Inspect for short to GND circuit between refrigerant
pressure switch and PCM terminal 84.
No Go to next step.
4 Reconnect refrigerant pressure switch
connector.Measure PCM terminal 84 voltage
while turning off A/C switch.
Note
•PCM terminal 84 voltage should read B+
when turning A/C switch off. If PCM
terminal 84 voltage reading remains
below 1.0 V, short to GND circuit maybe
present.
Does voltage remain B+?Yes Inspect for following:
•Short to GND circuit between A/C switch and A/C
amplifier.
•Short to GND circuit between A/C amplifier and
refrigerant pressure switch.
No Inspect for stuck closed A/C switch.
5 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)

F2–224
TROUBLESHOOTING
NO.25 A/C DOES NOT CUT OFF UNDER WIDE OPEN THROTTLE CONDITIONSA6E408018881227
Diagnostic Procedure
End Of Sie
25 A/C DOES NOT CUT OFF UNDER WIDE OPEN THROTTLE CONDITIONS
DESCRIPTION•A/C compressor magnetic clutch does not disengage under wide open throttle.
POSSIBLE
CAUSE•Accelerator position sensor malfunction
•Accelerator position sensor misadjustment
•Loosely installed accelerator position sensor
STEP INSPECTION RESULTS ACTION
1 Does A/C compressor disengage when A/C
switch is turned off?Yes Go to next step.
No Go to symptom troubleshooting “NO.24 A/C ALWAYS
ON OR A/C COMPRESSOR RUNS
CONTINUOUSLY”.
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:
Inspect adjustment of accelerator position sensor.
If accelerator position sensor adjustment is not
correct, adjust accelerator position sensor.
3 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)