2002 MAZDA 6 warning

F2–178
TROUBLESHOOTING
End Of Sie
NO.5 ENGINE STALLS-AFTER START/AT IDLEA6E408018881207
Diagnostic Procedure
18 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
5 ENGINE STALLS-AFTER START/AT IDLE
DESCRIPTION•Engine stops unexpectedly.
POSSIBLE
CAUSE•Poor fuel quality
•Intake-air system restriction or clogging
•Engine overheating
•A/C system improper operation
•Immobilizer system (PATS) and/or circuit malfunction (if equipped)
•PCM control relay malfunction
•Glow system malfunction
•Inadequate fuel pressure
•Fuel pressure sensor related circuit malfunction
•Suction control valve malfunction (built-in supply pump)
•Fuel pressure limiter malfunction (built-in common rail)
•Fuel leakage
•Fuel line clogging or restriction
•Fuel filter clogging or restriction
•Incorrect fuel injection timing
•Erratic signal from CKP sensor
•Erratic signal from CMP sensor
•Supply pump malfunction
•Fuel injector malfunction
•Low engine compression
•Improper valve timing
•Exhaust system and/or catalyst converter restriction or clogging
•EGR system malfunction
•ECT sensor or related circuit malfunction
•Accelerator positions sensor or related circuit malfunction
•Accelerator positions sensor misadjustment
•MAF/IAT sensor or related circuit malfunction
•V-reference voltage supply circuit 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
1Note
•The following test should be perform for
vehicles with immobilizer system. Go to
Step 10 for vehicles without immobilizer
system.
Connect WDS or equivalent to DLC-2.
Do following conditions appear?
•Engine is not completely started.
•DTC B1681 is displayed.YesBoth conditions appear:
Go to Step 4.
NoEither or other condition appears:
Go to next step.
2 Is coil connector securely connected to coil? Yes Go to next step.
No Connect coil connector securely.
Return to Step 1.
3 Does security light illuminate? Yes Go to next step.
No Inspect instrument cluster and wiring harness.

TROUBLESHOOTING
F2–181
F2
End Of Sie
NO.6 CRANKS NORMALLY BUT WILL NOT STARTA6E408018881208
Diagnostic Procedure
28 Inspect IDM.
(See F2–84 INJECTOR DRIVER MODULE
(IDM) INSPECTION)
Is IDM okay?Yes Go to next step.
No Repair or replace as necessary.
29 Inspect EGR system operation.
Is EGR system operation normal?Yes Remove and inspect supply pump and common rail.
No Repair or replace malfunctioning part according to
EGR system operation results.
30 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
6 CRANKS NORMALLY BUT WILL NOT START
DESCRIPTION•Starter cranks engine at normal speed but engine will not run.
•Refer to symptom troubleshooting “No.5 Engine stalls” if this symptom appears after engine stall.
•Fuel is in fuel tank.
•Battery is in normal condition.
POSSIBLE
CAUSE•Poor fuel quality
•Intake-air system restriction
•Fuel line restriction
•EGR system malfunction
•Glow system malfunction
•Fuel pressure sensor or related circuit malfunction
•Suction control valve malfunction (built-in supply pump)
•Fuel pressure limiter malfunction (built-in common rail)
•Fuel leakage
•Fuel filter clogging
•Incorrect fuel injection timing
•Erratic signal from CKP sensor
•Erratic signal from CMP sensor
•V-reference supply circuit malfunction
•ECT sensor or related circuit malfunction
•Supply pump malfunction
•Fuel injector malfunction
•Immobilizer system (PATS) and/or circuit malfunction (if equipped)
•Low engine compression
•Improper valve timing
•IDM or related circuit malfunction
•PCM control repay 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
1Note
•The following test should be perform for
vehicles with immobilizer system. Go to
Step 10 for vehicles without immobilizer
system.
Connect WDS or equivalent to DLC-2.
Do following conditions appear?
•Engine is not completely started.
•DTC B1681 is displayed.YesBoth conditions appear:
Go to Step 4.
NoEither or other condition appears:
Go to next step.
2 Is coil connector securely connected to coil? Yes Go to next step.
No Connect coil connector securely.
Return to Step 1.

F2–184
TROUBLESHOOTING
NO.7 SLOW RETURN TO IDLEA6E408018881209
Diagnostic Procedure
7 SLOW RETURN TO IDLE
DESCRIPTION•Engine takes more time than normal to return to idle speed.
•Engine speed continues at fast idle after warm-up.
POSSIBLE
CAUSE•Thermostat is stuck open
•Fuel injection timing is incorrect
•Erratic signal from CKP sensor
•Erratic signal from CMP sensor
•ECT sensor or related circuit malfunction
•Accelerator position sensor or related circuit malfunction
•Idle switch or related circuit malfunction
•MAF/IAT sensor or related circuit malfunction
•Fuel pressure sensor or related circuit malfunction
•Incorrect adjustment accelerator pedal position sensor and/or idle switch
•Incorrect idle speed
•Excessive fuel pressure
•Supply pump malfunction
•Suction control valve malfunction (built-in supply pump)
•Fuel pressure limiter malfunction (built-in common rail)
•Fuel injector malfunction (incorrect fuel regulate pressure)
•Neutral switch or related circuit 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 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 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.
2 Access ECT PID.
Start and warm-up engine to normal operating
temperature.
Is ECT PID reading between 82—112 °C {180—
233 °F}?Yes Go to next step.
NoECT PID is higher than 112 °C {233 °F}:
Go to symptom troubleshooting “NO.17 COOLING
SYSTEM CONCERNS-OVERHEATING”.
ECT PID is less than 82 °C {180 °F}:
Go to symptom troubleshooting “NO.18 COOLING
SYSTEM CONCERNS-RUNS COLD”.

F2–186
TROUBLESHOOTING
NO.8 ENGINE RUNS ROUGH/ROLLING IDLEA6E408018881210
Diagnostic Procedure
8 ENGINE RUNS ROUGH/ROLLING IDLE
DESCRIPTION•Engine speed fluctuates between specified idle speed and lower speed and engine shakes excessively.
•Idle speed is too slow and engine shakes excessively.
POSSIBLE
CAUSE•Poor fuel quality
•Air leakage from intake-air system
•Intake-air system restriction
•Incorrect idle speed
•Engine overheating
•Cooling fan No.1 system malfunction
•A/C system improper operation
•EGR system improper operation
•EGR water cooler malfunction
•Fuel leakage
•Inadequate fuel pressure
•Fuel pressure sensor or related circuit malfunction
•Suction control valve malfunction (built-in supply pump)
•Fuel pressure limiter malfunction (built-in common rail)
•Fuel filter clogging
•Fuel line restriction
•Incorrect fuel injection timing
•Erratic signal from CKP sensor
•Erratic signal from CMP sensor
•ECT sensor or related circuit malfunction
•Idle switch misadjustment
•Idle switch or related circuit malfunction
•Accelerator position sensor misadjustment
•Accelerator position sensor or related circuit malfunction
•MAF/IAT sensor malfunction
•Neutral switch or related circuit malfunction
•Supply pump malfunction
•Fuel injector malfunction
•Low engine compression
•Improper valve timing
•Engine compression excessive unbalance for each cylinder
•Unbalanced fuel injection amount for each cylinder
•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 Inspect for following:
•Fuel quality (e.g.: including water
contamination, winter/summer blend)
•Fuel line/fuel filter clogging
•Loose bands on intake-air system
•Cracks on intake-air system parts
•Intake-air system restriction
•Vacuum leakage
•Cooling fan No.1 system operation
Are all items okay?Yes Go to next step.
No Service as necessary
Repeat Step 1.
2 Is engine overheating? Yes Go to symptom troubleshooting “NO.17 COOLING
SYSTEM CONCERNS—OVERHEATING.”
No Go to next step.

TROUBLESHOOTING
F2–189
F2
NO.9 FAST IDLE/RUNS ONA6E408018881211
Diagnostic Procedure
End Of Sie
9 RUNS IDLE/RUNS ON
DESCRIPTION•Engine speed continues at fast idle after warm-up.
•Engine runs after engine key turned off.
POSSIBLE
CAUSE•ECT sensor or related circuit malfunction
•Incorrect adjustment accelerator position sensor and/or idle switch
•Suction control valve (built-in supply pump)
•Fuel injector malfunction
•IDM or related circuit malfunction
•Vacuum 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 Connect WDS or equivalent to DLC-2.
Access ECT PID.
Start and warm-up engine to normal operating
temperature.
Is ECT PID reading between 82—112 °C {180—
233 °F}?Yes Go to next step.
NoECT PID is higher than 112 °C{233 °F}:
Go to symptom troubleshooting “NO.17 COOLING
SYSTEM CONCERNS—OVERHEATING”.
ECT PID is less than 82 °C{180 °F}:
Go to symptom troubleshooting “NO.18 COOLING
SYSTEM CONCERNS—RUNS COLD”.
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 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)
4 Inspect fuel injector.
(See F2–56 FUEL INJECTOR INSPECTION)
Is fuel injector okay?Yes Go to next step.
No Replace fuel injector.
(See F2–55 FUEL INJECTOR REMOVAL/
INSTALLATION)
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 Inspect vacuum leakage.
No Adjust accelerator position sensor and idle switch
correctly.
(See F2–73 ACCELERATOR POSITION SENSOR
ADJUSTMENT)
(See F2–71 IDLE SWITCH ADJUSTMENT)
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)

F2–190
TROUBLESHOOTING
NO.10 LOW IDLE/STALLS DURING DECELERATIONA6E408018881212
Diagnostic Procedure
10 LOW IDLE/STALLS DURING DECELERATION
DESCRIPTION•Engine stops unexpectedly at beginning of deceleration or recovery from deceleration.
POSSIBLE
CAUSE•Intake-air system restriction or clogging
•Poor fuel quality
•A/C system improper operation
•Inadequate fuel pressure
•Suction control valve malfunction (built-in supply pump)
•Fuel pressure limiter malfunction (built-in common rail)
•Fuel leakage
•Fuel line restriction or clogging
•Fuel filter restriction or clogging
•Incorrect fuel injection timing
•Incorrect idle speed
•Erratic signal from CKP sensor
•Erratic signal from CMP sensor
•Supply pump malfunction
•Fuel injector malfunction
•Low engine compression
•Improper valve timing
•Glow system malfunction
•EGR system malfunction
•MAF/IAT sensor or related circuit malfunction
•ECT sensor or related circuit malfunction
•Fuel pressure sensor or related circuit malfunction
•Neutral switch malfunction or related circuit malfunction
•Accelerator position sensor or related circuit malfunction
•Idle switch or related circuit malfunction
•Incorrect adjustment accelerator position sensor and/or idle switch
•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 Does engine idle rough? Yes Go to symptom troubleshooting “NO.8 ENGINE RUNS
ROUGH/ROLLING IDLE”.
No Go to next step.
2 Inspect for following:
•Fuel line/fuel filter clogging or restriction
•Intake-air system restriction or clogging
•Fuel quality (e.g.: include water
contamination, winter/summer blend)
Are all items okay?Yes Go to next step.
No Service as necessary.
Repeat Step 2.
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.
4 Inspect idle speed.
(See F2–34 IDLE SPEED INSPECTION)
Is idle speed correct?Yes Go to next step.
No Repair or replace malfunctioning part according to idle
speed inspection results.

F2–192
TROUBLESHOOTING
End Of Sie
NO.11 ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE,
SURGES
A6E408018881213
17 Inspect IDM.
(See F2–84 INJECTOR DRIVER MODULE
(IDM) INSPECTION)
Is IDM okay?Yes Remove and inspect supply pump and common rail.
No Repair or replace as necessary.
18 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
11ENGINE STALLS/QUITS, ENGINE RUNS ROUGH, MISSES, BUCK/JERK, HESITATION/STUMBLE,
SURGES
DESCRIPTION•Engine stops unexpectedly at beginning of acceleration or during cruise.
•Engine stops unexpectedly while cruising.
•Engine speed fluctuates during acceleration or cruising.
•Engine misses during acceleration or cruising.
•Vehicle bucks/jerks during acceleration, during or deceleration.
•Momentary pause at beginning of acceleration or during acceleration.
•Momentary minor irregularity in engine output.
POSSIBLE
CAUSE•Poor fuel quality
•Glow system malfunction
•Air leakage from intake-air system
•Intake-air system restriction or clogging
•Engine overheating
•A/C system improper operation
•Turbocharger malfunction
•Variable swirl control (VSC) system malfunction
•EGR system malfunction
•Neutral switch or related circuit malfunction
•Cooling fan No.1 or cooling fan No.2 seat are improper
•Fuel line clogging or restriction
•Fuel filter clogging or restriction
•Incorrect fuel injection timing
•Erratic signal from CKP sensor
•Erratic signal from CMP sensor
•ECT sensor or related circuit malfunction
•Boost sensor or related circuit malfunction
•Accelerator position sensor or related circuit malfunction
•Idle switch or related circuit malfunction
•MAF/IAT sensor or related circuit malfunction
•IAT sensor No.2 or related circuit malfunction
•VSS or related circuit malfunction
•Incorrect adjustment accelerator position sensor and/or idle switch
•Incorrect idle speed
•Inadequate fuel pressure
•Fuel pressure sensor or related circuit malfunction
•Suction control valve malfunction (built-in supply pump)
•Fuel pressure limiter malfunction (built-in common rail)
•Supply pump malfunction
•Fuel injector malfunction
•Low engine compression
•Improper valve timing
•Exhaust system and/or catalyst converter restriction
•Clutch slippage
•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.

TROUBLESHOOTING
F2–195
F2
NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISEA6E408018881214
Diagnostic Procedure
12 LACK/LOSS OF POWER-ACCELERATION CRUISE
DESCRIPTION•Performance is poor under load (e.g., power down when climbing hills).
POSSIBLE
CAUSE•Poor fuel quality
•Air leakage from intake-air system
•Intake-air system restriction or clogging
•Engine overheating
•A/C system improper operation
•Improper operation of A/C cut-off control
•Variable boost control (VBC) system malfunction
•Variable swirl control (VSC) system malfunction
•EGR system malfunction
•Vacuum leakage
•Clutch slippage
•Exhaust system and/or catalyst converter restriction
•Fuel line or clogging or restriction
•Fuel filter clogging or restriction
•Incorrect fuel injection timing
•Erratic signal from CKP sensor
•Erratic signal from CMP sensor
•ECT sensor or related circuit malfunction
•Boost sensor or related circuit malfunction
•Accelerator position sensor or related circuit malfunction
•Idle switch or related circuit malfunction
•MAF/IAT sensor or related circuit malfunction
•IAT sensor No.2 or related circuit malfunction
•Incorrect adjustment accelerator position sensor and/or idle switch
•Incorrect idle speed
•Inadequate fuel pressure
•Fuel pressure sensor or related circuit malfunction
•Suction control valve malfunction (built-in supply pump)
•Fuel pressure limiter malfunction (built-in common rail)
•Supply pump malfunction
•Fuel injector malfunction
•Low engine compression
•Improper valve timing
•Cooling fan No.1 or cooling fan No.2 seat are improper
•Turbocharger malfunction
•Charge air cooler malfunction
•Brake system dragging
•Intake shutter valve malfunction
•Guide blade valve 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 idle speed stable? Yes Go to next step.
No Go to symptom troubleshooting “NO.8 ENGINE RUNS
ROUGH/ROLLING IDLE”.
2 Is engine overheating? Yes Go to symptom troubleshooting “NO.17 COOLING
SYSTEM CONCERNS—OVERHEATING”.
No Go to next step.