2002 MAZDA 6 ECU

F1–40
CONTROL SYSTEM
2TCoil*
9 (Immobilizer
system)CoilBecause this terminal is for communication,
good/no good judgment by terminal voltage
is not possible.•Inspect coil
•Inspect related
harness
—*
10————
2U CAN (+)Instrument cluster,
ABS HU/CM,
ABS/TCS HU/CM,
DSC HU/CM,
TCM*
12
Because this terminal is for CAN, good/no
good judgment by terminal voltage is not
possible.•Inspect related
harness
2V—— — ——
2WSecurity light
control*
9Instrument cluster
(Security light)Security light illuminate—
•Inspect related
harness
Others Below 1.0
—*
10————
2X Main relay control Main relayIgnition switch OFF B+•Inspect main relay
•Inspect related
harness Ignition switch ON Below 1.0
2Y B+ Main relayIgnition switch OFF Below 1.0•Inspect battery
•Inspect related
harness Ignition switch ON B+
2ZBack-up power
supplyBattery (positive
terminal)Under any condition B+•Inspect battery
•Inspect related
harness
2AA—— — ——
2AB GND GND Under any condition Below 1.0•Inspect related
harness
2AC GND GND Under any condition Below 1.0•Inspect related
harness
2AD—— — ——
3A—— — ——
3B—— — ——
3CVehicle speed*
3VSS•Inspect using the wave profile.
(See F1–44 Inspection Using An
Oscilloscope (Reference).)•Inspect VSS
•Inspect related
harness
—*
13————
3DATF temperature*
11TFT sensorIgnition switch
ONTFT 20 °C
{68 °F}Approx.
3.3
•Inspect TFT sensor
•Inspect related
harness TFT 40 °C
{104 °F}Approx.
2.4
TFT 60 °C
{140 °F}Approx.
1.5
—*
14————
3E—— — ——
3F—— — ——
3GInput/turbine speed
sensor (+)*
11Input/turbine
speed sensor•Inspect using the wave profile.
(See F1–44 Inspection Using An
Oscilloscope (Reference).)•Inspect input/turbine
speed sensor
•Inspect related
harness
—*
14————
3H—— — ——
3I—— — ——
3JInput/turbine speed
sensor (–)*
11Input/turbine
speed sensor•Inspect using the wave profile.
(See F1–44 Inspection Using An
Oscilloscope (Reference).)•Inspect input/turbine
speed sensor
•Inspect related
harness
—*
14———— Terminal Signal Connected to Test conditionVoltage
(V)Action

INTAKE-AIR SYSTEM
F2–37
F2Air Pipe Removal Note
1. Remove the battery and the battery tray before removing the air pipe. (See G–5 BATTERY REMOVAL/
INSTALLATION.)
Intake Manifold Removal Note
1. Remove the supply pump before removing the intake manifold. (See F2–53 SUPPLY PUMP REMOVAL/
INSTALLATION.)
2. Remove the EGR valve before removing the intake manifold. (See F2–59 EGR VALVE REMOVAL/
INSTALLATION.)
Air Cleaner Case Installation Note
Note
•Before assembling the air cleaner, verify that the rubber mounts have not fallen off from the air cleaner
bracket (3 locations).
•Always install the air cleaner case using the following procedure.
•When inserting the rubber mounts into the air cleaner case, soapy water can be applied.
1. Verify that the rubber mounts are set in the air cleaner bracket (3 locations).
2. Install the projections on the frame side (2 locations).
3. Verify that the projections on the frame side are installed securely.
4. Install the projection on the engine side (remaining location).
5. Verify that the projection on the engine side installed securely.
End Of Sie
AIR CLEANER ELEMENT INSPECTIONA6E4010010052041. Remove the air cleaner element. (See F2–36 INTAKE-AIR SYSTEM REMOVAL/INSTALLATION.)
2. Verify that the air cleaner element surface is free of dirt.
•If there is dirt present, use an air gun or similar tool to clean the element.
•If the replacement time limit has passed, replace the element.
End Of Sie
1 Vacuum hose
2 Air hose
3 Air cleaner cover
4 Air cleaner element
5Air cleaner case
(See F2–37 Air Cleaner Case Installation Note)
6 MAF/IAT sensor
7Air pipe
(See F2–37 Air Pipe Removal Note)
8 Vacuum pipe
9 Air hose
10 Air pipe11 Air hose
12 Air pipe
13 Boost sensor
14 IAT sensor No. 2
15 Air pipe
16 Air hose
17 Air duct
18 Charge air cooler
19 Vacuum hose (Intake shutter valve actuator)
20 Vacuum hose (VSC shutter valve actuator)
21Intake manifold
(See F2–37 Intake Manifold Removal Note)

FUEL SYSTEM
F2–49
F2
(2) Apply a slight amount of clean engine oil to
the sealing surface of the fuel pump unit.
(3) Align the fuel pipe on the fuel pump unit and
quick release connector so that the tabs of the
retainer are correctly fitted into the quick
release connector. Push the quick release
connector straight into the retainer until a click
is heard.
(4) Lightly pull and push the quick release
connector a few times by hand and verify that
it can move 2.0—3.0 mm {0.08—0.11 in} and
it is connected securely.
•If the quick release connector does not
move at all, verify that O-ring is not
damaged of that is has not slipped, and reconnect the quick release connector.
2. When the retainer is removed, perform the following procedure.
End Of Sie
FUEL TANK INSPECTIONA6E401242110202
Caution
•Disconnecting/connecting the quick release connector without cleaning it may possibly cause
damage to the fuel pipe and quick release connector. Always clean the quick release connector
joint area before disconnecting/connecting using a cloth or soft brush, and make sure that it is
free of foreign material.
Note
•This inspection is for two rollover valves and check valve (two-way) integrated in the fuel tank.
1. Remove the fuel tank with the fuel gauge sender unit. (See F2–45 FUEL TANK REMOVAL/INSTALLATION.)
2. Plug the fuel pipe of the fuel gauge sender unit.
3. Plug port C.
4. Connect the pump to port B.
5. Level the fuel tank.
6. Apply pressure of +2.0 kpa {+34 mmHg, +1.3
inHg} to port B.
(1) Verify there is airflow from port A.
•If there is no airflow, replace the fuel tank.
7. Apply pressure of –5.9 kPa {–44 mmHg, –1.7
inHg} to port B.
•If there is no vacuum, replace the fuel tank.
•If there is vacuum, turn the fuel tank
upside-down and proceed to next step.
8. Apply pressure of +2.0 kPa {+15 mmHg, +0.6
inHg} to port B.
(1) Verify there is no airflow from port A.
•If there is airflow, replace the fuel tank.
End Of Sie
OILOIL
PLASTIC FUEL HOSE QUICK RELEASE
CONNECTOR SEALING
SURFACE
A6E3912W006
B
C
APLUG
PLUG
CHECK VALVE
(TWO-WAY)
FUEL GAUGE SENDER UNIT
ROLLOVER VALVE
A6E40122034
B CA
PLUGPLUG
CHECK VALVE
(TWO-WAY)
FUEL GAUGE SENDER UNIT
ROLLOVER VALVE
A6E40122035

CONTROL SYSTEM
F2–71
F2
IDLE SWITCH ADJUSTMENTA6E404041600202
Caution
•Adjusting the idle switch unnecessarily may adversely affect engine control. Therefore, adjust the
idle switch only when it is replaced.
1. Verify that the accelerator position sensor is normal.
2. Visually inspect all accelerator pedal components for looseness.
3. Loosen the locknut that secures the idle switch.
4. Verify that the power circuit voltage.
(1) Verify that the voltage between the PCM terminals 90 (power circuit) and 91(GND circuit) is 4.75—5.25 V.
Note
•Voltage at the PCM terminal 10 may deviate when the power circuit voltage is abnormal.
5. Depress the accelerator pedal by hand and
secure it when the voltage between the PCM
terminals 10 (accelerator position detection
signal) and 91 is within the range specified below.
Voltage range
0.9—1.1V (Target value: 1.0 V)
6. Turn the idle switch under the condition in Step 5.
Secure the idle switch when the continuity turns
from OFF to ON, and tighten the locknut.
7. Release the accelerator pedal. Depress the
accelerator pedal again and verify that the idle
switch continuity changes from OFF to ON when
the PCM terminal 10 voltage is within 0.9—1.1 V.
•If the continuity does not change, repeat Step
6.
End Of Sie
ACCELERATOR POSITION SENSOR
IDLE SWITCHPCM B
A
C
D
A
B31 10
90
88
91
A6E40702037
ACCELERATOR PEDAL
A6E40702039
IDLE SWITCH
LOCKNUTA
B
A6E40702040

F2–174
TROUBLESHOOTING
NO.2 MIL ILLUMINATESA6E408018881204
Diagnostic procedure
End Of Sie
NO.3 WILL NOT CRANKA6E408018881205
Diagnostic procedure
2 MIL ILLUMINATES
DESCRIPTION•MIL illuminates incorrectly.
POSSIBLE
CAUSE•PCM illuminates for emission-related concern (DTC is stored in PCM)
•Instrument cluster malfunction
Note
•If MIL blinks at steady rate, misfire condition could possibly exist.
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.
NoNo DTC is displayed:
•Inspect instrument cluster operation.
2 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)
3 WILL NOT CRANK
DESCRIPTION•Starter does not work.
POSSIBLE
CAUSE•Open starter circuit between engine switch and starter
•Starter malfunction
•Seized/hydrolocked engine, flywheel
•Immobilizer system (PATS) and/or circuit malfunction (if equipped)
•Low or dead battery
•Charging system malfunction
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.
4 Connect WDS or equivalent to DLC-2 and
retrieve DTC.
DTC
B1213, B1342, B1600, B1601, B1602, B1681,
B2103, B2431Yes Go to appropriate DTC test.
No Go to next step.

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.

F2–182
TROUBLESHOOTING
3 Does security light illuminate? Yes Go to next step.
No Inspect instrument cluster and wiring harness.
4 Connect WDS or equivalent to DLC-2 and
retrieve DTC.
DTC
B1213, B1342, B1600, B1601, B1602, B1681,
B2103, B2431Yes Go to appropriate DTC test.
No Go to next step.
5 Is there continuity between PCM GND terminals
65, 85, 103, 104 and GND?Yes Go to next step.
No Repair or replace wiring harness.
6 Measure voltage between PCM GND terminals
65, 85, 103, 104 and coil terminal C.
Is the voltage below 1.0?Yes Go to next step.
No Repair or replace wiring harness.
7 Turn engine switch to ON.
Access VPWR PID.
Is VPWR PID okay?
Specification
Battery voltageYes Go to next step.
No Repair or replace wiring harness.
8 Disconnect coil connector.
Turn engine switch to ON.
Is there battery voltage at coil connector terminal
D (harness-side)?Yes Inspect for following:
•Open or short circuit between coil terminal A and
PCM terminal 80
•Open or short circuit between coil terminal B and
PCM terminal 28
No Repair or replace wiring harness between coil
connector terminal D and fuse panel.
9 Is there continuity between PCM terminal 57 and
starter relay?Yes Go to next step.
No Repair replace wiring harness.
10 Inspect for following:
•Fuel quality (e.g.: include water
contamination, winter/summer blend)
•Fuel line/fuel filter clogging
•Intake-air system restriction
Are all items okay?Yes Go to next step.
No Service as necessary.
Repeat Step 10.
11Note
•Ignore DTC P0122, P0123, P0222 or
P0223 while performing this test.
Disconnect accelerator position sensor
connector.
Measure voltage at accelerator position sensor
connector VREF terminal (terminal D) with
engine switch ON.
Specification
4.5—5.5 V
Is voltage okay?Yes Go to next step.
No Go to symptom troubleshooting “NO.26 CONSTANT
VOLTAGE”.
12 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. STEP INSPECTION RESULTS ACTION