
TROUBLESHOOTING
F2–199
F2
NO.13 KNOCKING/PINGINGA6E408018881215
Diagnostic Procedure
13 KNOCKING/PINGING
DESCRIPTION•Excessive shrilly knocking sound from engine.
POSSIBLE
CAUSE•Poor fuel quality
•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
•Glow system malfunction
•Low engine compression
•Improper valve timing
•Low coolant temperature
•Incorrect fuel injection timing
•Erratic signal from CKP sensor
•Erratic signal from CMP sensor
•ECT sensor or related circuit malfunction
•MAF/IAT sensor or related circuit malfunction
•IAT sensor No.2 or related circuit malfunction
•Boost sensor or related malfunction
•Fuel pressure sensor or related circuit malfunction
•Accelerator position sensor or related circuit malfunction
•Excessive fuel pressure
•Fuel return line clogging or restriction
•EGR system malfunction
•Exhaust system and/or catalyst converter restriction
•Turbocharger malfunction
•Charge air cooler malfunction
•Suction control valve malfunction (built-in supply pump)
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 run cold? Yes Go to symptom troubleshooting “NO.18 COOLING
SYSTEM CONCERNS—RUNS COLD”.
No Go to next step.
2 Inspect for following:
•Fuel quality (e.g.: including water
contamination, winter/summer blend)
•Fuel return line clogging and/or restriction
•Intake-air system restriction or clogging
•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 2.
3 Connect WDS or equivalent to DLC-2.
Access ECT PID.
Verify ECT PID is above 80 °C {176 °F}?Yes Go to next step.
No Inspect ECT PID.

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
F2–205
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.

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

K2–142
ON-BOARD DIAGNOSTIC
End Of SieDTC P0740A6E577018901212
Diagnostic procedure
12VERIFY TROUBLESHOOTING OF DTC P0720
COMPLETED
•Make sure to reconnect all disconnected
connectors.
•Clear DTC from memory using WDS or
equivalent.
•Drive vehicle with vehicle speed 40 km/h {25
mph} or above for 2 second or more
•Is same DTC present?Yes Replace TCM, then go to next step.
(See K2–96 TCM REMOVAL/INSTALLATION.)
No Go to next step.
13VERIFY AFTER REPAIR PROCEDURE
•Perform “After Repair Procedure”.
(See K2–124 AFTER REPAIR PROCEDURE.)
•Is there any DTC present?Yes Go to applicable DTC inspection.
No Troubleshooting completed. STEP INSPECTION ACTION
DTC P0740 TCC system malfunction
DETECTION
CONDITION•RPM difference between crankshaft (engine speed signal) and reverse clutch drum (input/turbine speed
sensor signal) exceeds the pre-programmed value.
Diagnostic support note:
•This is continuous monitor (CCM).
•MIL illuminates if TCM detects the above malfunction conditions in two consecutive drive cycles.
•PENDING CODE is available.
•FREEZE FRAME DATA is available.
•AT warning light does not indication.
•DTC is stored in TCM memory.
POSSIBLE
CAUSE•ATF level low.
•Deteriorated ATF.
•TCC solenoid valve and pressure control solenoid stuck.
•Line pressure low.
•Oil pump malfunction.
•Control valve stuck
•Torque convert clutch malfunction
•TCM malfunction.
STEP INSPECTION ACTION
1VERIFY FREEZE FRAME DATA HAS BEEN
RECORDED
•Has FREEZE FRAME PID DATA been
recorded?Yes Go to next step.
No Record FREEZE FRAME PID DATA on repair order, then
go to next step.
2VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
•Check for related Service Bulletins and/or on-
line repair information availability.
•Is any related repair information available?Yes Perform repair or diagnosis according to available repair
information.
•If vehicle is not repaired, go to next step.
No Go to next step.
3CHECK ATF CONDITION
•Turn ignition key to OFF.
•Check ATF condition.
—Clear red: Normal
—Milky: Water mixed in fluid
—Reddish brown: Deteriorated ATF
•Is it okay?
(See K2–78 Automatic Transaxle Fluid (ATF)
Condition Inspection.)Yes Go to next step.
No If ATF color milky or reddish brown, replace ATF, then go to
Step 5.
(See K2–80 AUTOMATIC TRANSAXLE FLUID (ATF)
REPLACEMENT.)
4CHECK ATF LEVEL
•Start engine.
•Warm up ATX.
•Is ATF level within specification?
(See K2–79 Automatic Transaxle Fluid (ATF)
Level Inspection.)Yes Go to next step.
No Adjust ATF level, then go to Step 9.
(See K2–79 Automatic Transaxle Fluid (ATF) Level
Inspection.)

U–1
U
UHEATER AND AIR CONDITIONER SYSTEMS
OUTLINE................................................................ U-2
OUTLINE OF CONSTRUCTION.......................... U-2
FEATURES .......................................................... U-2
SPECIFICATIONS ............................................... U-2
CONTROL SYSTEM............................................... U-6
WATER HEATER SYSTEM................................. U-6
OUTLINE................................................................ U-7
SUPPLEMENTAL SERVICE INFORMATION .....U-7
LOCATION INDEX.................................................U-8
BASIC SYSTEM................................................... U-8
CONTROL SYSTEM ............................................ U-9
BASIC SYSTEM................................................... U-10
A/C UNIT REMOVAL/INSTALLATION...............U-10
A/C COMPRESSOR
REMOVAL/INSTALLATION ............................U-11
CONDENSER REMOVAL/INSTALLATION ....... U-12
REFRIGERANT LINES
REMOVAL/INSTALLATION ............................U-13
CONTROL SYSTEM............................................. U-15
WATER HEATER UNIT
REMOVAL/INSTALLATION ............................U-15
FUEL PUMP (WATER HEATER SYSTEM)
INSPECTION .................................................. U-16
CLIMATE CONTROL UNIT INSPECTION.........U-16
ON-BOARD DIAGNOSTIC...................................U-22
FOREWORD ......................................................U-22
DTC TABLE ................................................... U-22-2
PID/DATA MONITOR AND RECORD ........... U-22-2
DTC B1317 .................................................... U-22-3
DTC B1318 ........................................................ U-23
DTC B1342, B2463, B2537, B2538, B2547 ....... U-23
DTC B2449, B2450 ............................................ U-24
DTC B2451, B2452 ............................................ U-24
DTC B2453, B2454 ............................................ U-25
DTC B2548 ........................................................ U-25
TROUBLESHOOTING.......................................... U-26
FOREWORD ......................................................U-26
TROUBLESHOOTING INDEX ...........................U-26 FEATURES
SERVICE

U–6
CONTROL SYSTEM
WATER HEATER SYSTEMA6E854000169201Outline
•The function, structure and operation of the water heater system is essentially carried over from that of the
current MPV (LW) model, except for following:
—Full/half switching temperature has been changed.
Structural View
.
Operation
Full/half switching
•Depending on the engine coolant temperature, the CPU sets the flame to either full or half strength settings.
.
End Of Sie
CONTROL SYSTEM
1
2
A6E85402002
1 Water heater unit2 Fuel pump (water heater system)
3
1
2
68
{154}74
{165}75
{167}78
{172}˚C
{˚F}
A6E85402003
1 Full mode
2 Half mode3 Idle mode

OUTLINE
U–7
U
SUPPLEMENTAL SERVICE INFORMATIONA6E850201038204•The following additions have been made for the MZR-CD (RF Turbo) since the publication of the Mazda6
Workshop Manual (1730-1*-02C).
A/C unit
•Removal/installation procedure has been modified.
A/C compressor
•Removal/installation procedure has been modified.
Condenser
•Removal/installation procedure has been modified.
Refrigerant lines
•Removal/installation procedure has been modified.
Water heater unit
•Removal/installation procedure has been added.
Fuel pump (water heater system)
•Inspection procedure has been added.
Climate control unit
•Inspection procedure has been modified.
Water heater system
•On-board diagnostic system has been added.
End Of Sie
OUTLINE