2002 MAZDA 6 engine

OUTLINE
U–3
U
Bold frames: New specification
Refrigerant pressure
switchType Dual-pressure: General area
Operating pressure
(MPa {kgf/cm
2, psi})
TypeTriple-pressure: L3 engine,
intensely hot area
– Operating pressure
(MPa {kgf/cm
2, psi})
Thermal protectorType Bimetallic (Indirect sensing type)
Operating temperature
(°C {°F})
Temperature control Reheat full air mix typeItemSpecification
L3, L8, LF MZR-CD (RF Turbo)
ON
OFF0.166—0.226
{1.693—2.304,
24.08—32.77}2.94—3.34
{30.0—34.0,
427—483}
0.02
{0.20, 2.84}
or less0.39—0.79
{3.98—8.05,
56.6—114}
0.195—0.250
{1.989—2.549, 28.30—36.24}
ON
OFF
ON
OFF  HI and LO pressure switch
 Middle pressure switch0.176—0.216
{1.795—2.202,
25.53—31.31}2.94—3.34
{30.0—34.0,
427—483}
0.02 {0.20,
2.84} or less0.39—0.79
{3.98—8.05,
56.6—114}
0.195—0.250 {1.989—2.549,
28.30—36.24}
1.08—1.38
{11.1—14.0, 158—199}
1.39—1.65
{14.2—16.8,
202—238}
ON
OFF145—155
{293—311}:
European
(L.H.D. U.K.)
specs.
150—155
{302—311}:
GCC specs.
123—137 {254—278}
ON
OFF135—145
{275—293}
113—127 {236—260}

OUTLINE
U–5
U
Bold frames: New specificationEnd Of Sie
Refrigerant pressure
switchType Dual-pressure: General area
Operating pressure
(MPa {kgf/cm
2, psi})
TypeTriple-pressure: L3 engine,
intensely hot area
– Operating pressure
(MPa {kgf/cm
2, psi})
Thermal protectorType Bimetallic (Indirect sensing type)
Operating temperature
(°C {°F})
SensorSolar radiation sensor Photodiode
Ambient temperature sensor
Thermistor Cabin temperature sensor
Evaporator temperature
sensor
Water temperature sensor
ActuatorAir intake actuator Sliding contact type
Air mix actuator, airflow mode
actuatorPotentiometer type
Temperature control Reheat full air mix typeItemSpecification
L3, L8, LF MZR-CD (RF Turbo)
ON
OFF0.166—0.226
{1.693—2.304,
24.08—32.77}2.94—3.34
{30.0—34.0,
427—483}
0.02
{0.20, 2.84}
or less0.39—0.79
{3.98—8.05,
56.6—114}
0.195—0.250
{1.989—2.549, 28.30—36.24}
ON
OFF
ON
OFF  HI and LO pressure switch
 Middle pressure switch0.176—0.216
{1.795—2.202,
25.53—31.31}2.94—3.34
{30.0—34.0,
427—483}
0.02 {0.20,
2.84} or less0.39—0.79
{3.98—8.05,
56.6—114}
0.195—0.250 {1.989—2.549,
28.30—36.24}
1.08—1.38
{11.1—14.0, 158—199}
1.39—1.65
{14.2—16.8,
202—238}
ON
OFF145—155
{293—311}:
European
(L.H.D. U.K.)
specs.
150—155
{302—311}:
GCC specs.
123—137 {254—278}
ON
OFF135—145
{275—293}
113—127 {236—260}

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

U–10
BASIC SYSTEM
A/C UNIT REMOVAL/INSTALLATIONA6E8516611302011. Disconnect the negative battery cable.
2. Discharge the refrigerant from the system.
3. Drain the engine coolant.
4. Remove the dashboard.
5. Remove the theft-deterrent control module.
Caution
•If moisture or foreign material enters the refrigeration cycle, cooling ability will be lowered and
abnormal noise will occur. Always immediately plug open fittings after removing any refrigeration
cycle parts to keep moisture or foreign material out of the cycle.
6. Remove in the order indicated in the table. Do not allow compressor oil to spill.
.
BASIC SYSTEM
1
L.H.D.R.H.D.
3
2
R
R
N·m {kgf·cm, in·lbf} 6.86—9.80
{70.0—99.9,
60.8—86.7}
R
R
3
2
1
4
A6E85162001
1 Heater hose
2 Cooler pipe No.4 (L.H.D.) or cooler pipe No.5
(R.H.D.)
(See U–13 REFRIGERANT LINES REMOVAL/
INSTALLATION) (R.H.D.)
(See U–13 REFRIGERANT LINES REMOVAL/
INSTALLATION)3 Cooler pipe No.3
(See U–13 REFRIGERANT LINES REMOVAL/
INSTALLATION) (R.H.D.)
(See U–13 REFRIGERANT LINES REMOVAL/
INSTALLATION)
4A/C unit
(See U–11 A/C Unit Installation Note)

BASIC SYSTEM
U–13
U
REFRIGERANT LINES REMOVAL/INSTALLATIONA6E8516614602011. Remove the battery.
2. Discharge the refrigerant from the system.
3. Remove the washer tank.
4. Remove the air cleaner cover, air cleaner element and air cleaner case. (See F2–36 INTAKE-AIR SYSTEM
REMOVAL/INSTALLATION.)
5. Remove the sedimentor.
6. Remove the No.3 engine mount.
7. Remove the water heater unit.
8. Remove the shroud panel.
9. Remove the right splash shield.
Caution
•If moisture or foreign material enters the refrigeration cycle, cooling ability will be lowered and
abnormal noise will occur. Always immediately plug all open fittings after removing any
refrigeration cycle parts to keep moisture or foreign material out of the cycle.
10. Remove in the order indicated in the table. Do not allow compressor oil to spill.
11. Install in the reverse order of removal.

BASIC SYSTEM, CONTROL SYSTEM
U–15
U
End Of Sie
WATER HEATER UNIT REMOVAL/INSTALLATIONA6E854000170201
Caution
•If the negative battery cable is disconnected during the purge cycle of the water heater unit, the
gas in the unit may not be properly scavenged, causing white smoke (unburnt gas) to emit from
the exhaust pipe. Before disconnecting the negative battery cable, verify that the water heater unit
is not operating (no blower fan operation noise).
1. Complete the “BEFORE REPAIR PROCEDURE”. (See F2–45 BEFORE REPAIR PROCEDURE.)
2. Disconnect the negative battery cable.
3. Drain the engine coolant.
4. Remove the fuel filter with the pipes still connected, and fix the fuel filter using a rope so that it is out of the way.
5. Remove in the order indicated in the table.
6. Install in the reverse order of removal.
7. Complete the “AFTER REPAIR PROCEDURE”. (See F2–45 AFTER REPAIR PROCEDURE.)
8. Refill the engine coolant.
.
End Of Sie
1 Cooler pipe No.1
2 Cooler pipe No.2
3 Cooler pipe No.3
4 Cooler pipe No.45 Cooler pipe No.5 (R.H.D. only)
6 Cooler hose (HI)
7 Cooler hose (LO)
CONTROL SYSTEM
A
A
B
B
5
4
3
1
2
6
TO
FUEL PIPE
8.9—12.7
{90—130, 79—112}
N·m {kgf·cm, in·lbf}
8.9—12.7
{90—130, 79—112}
A6E85402004
1 Connector
2 Heater hose No.1
3 Heater hose No.34 Water heater unit
5 Fuel pump (water heater system)
6 Exhaust pipe

U–22–2
ON-BOARD DIAGNOSTIC
PID/Data Monitor and Record Procedure
1. Connect SST (WDS or equivalent) to the vehicle
DLC-2 16-pin connector located as shown in the
figure.
2. Access and monitor PIDs by WDS or equivalent.
End Of SieDTC TABLEA6E857001038202
* : If a DTC not listed above is detected, there is a water heater malfunction, and the water heater must be
replaced.
End Of SiePID/DATA MONITOR AND RECORDA6E857001038209PID Monitoring Item Table
DLC-2
A6E3970W002
DTC Possible cause Page
B1317 Input voltage high (See U–22–3 DTC B1317)
B1318 Input voltage low (See U–23 DTC B1318)
B1342 Malfunction in water heater unit(See U–23 DTC B1342, B2463,
B2537, B2538, B2547)
B2449 Glow plug circuit short to ground (See U–24 DTC B2449, B2450)
B2450 Glow plug circuit open (See U–24 DTC B2449, B2450)
B2451 Fuel pump circuit short to ground (See U–24 DTC B2451, B2452)
B2452 Fuel pump circuit open (See U–24 DTC B2451, B2452)
B2453 Blower fan circuit short to ground (See U–25 DTC B2453, B2454)
B2454 Blower fan circuit open (See U–25 DTC B2453, B2454)
B2463 Overheat(See U–23 DTC B1342, B2463,
B2537, B2538, B2547)
B2537 Water heater system does not start(See U–23 DTC B1342, B2463,
B2537, B2538, B2547)
B2538 Unstable flame(See U–23 DTC B1342, B2463,
B2537, B2538, B2547)
B2547 Flame prior to operation(See U–23 DTC B1342, B2463,
B2537, B2538, B2547)
B2548 Water heater lockout mode (See U–25 DTC B2548)
PID Name
(Definition)Unit/
ConditionCondition/Specification
(Reference)ActionWater
Heater Unit
terminal
CCNTFFH
(Number of continuous
codes)—•DTC is detected: 1—255
•DTC is not detected: 0Perform inspection
using appropriate
DTC.—
ECT
(Engine coolant temperature)°C°F•ECT 20 °C {68 °F}: 20 °C {68 °F}
•ECT 60 °C {140 °F}: 60 °C {140 °F}——
VPWR_FFH
(Module supply voltage)V•Ignition switch ON: B+Inspect water heater
unit power supply
terminal.A
VPWR_LMT
(Low voltage threshold)V•Ignition switch ON: approx. 9.5 VInspect water heater
unit power supply
terminal.A
FAN
(Fan control)%•Blower fan is not operating: 0 %
•Blower fan is operating: 0—100 %——
GPD
(Glow plug duty cycle)%•Water heater unit is not operating: 0 %
•Water heater unit is operating: 0—100 %——
BLOWRMTR
(Blower motor)On/Off•Blower fan is not operating: Off
•Blower fan is operating: On——

U–24
ON-BOARD DIAGNOSTIC
DTC B2449, B2450A6E857001038206
Diagnostic procedure
End Of Sie
DTC B2451, B2452A6E857001038207
Diagnostic procedure
DTCB2449 Glow plug circuit short to ground
B2450 Glow plug circuit open
DETECTION
CONDITION•CPU detects malfunction in glow plug circuit
POSSIBLE
CAUSE•Water heater unit malfunction
STEP INSPECTION ACTION
1INSPECT WATER HEATER UNIT
•Replace the water heater unit. (See U–15
WATER HEATER UNIT REMOVAL/
INSTALLATION)
•Perform the combustion Test. (See U–22 KOEO
Self Test/Combustion Test.)
•Are any DTCs present?Yes Go to the applicable DTC troubleshooting.
No Troubleshooting completed.
DTCB2451 Fuel pump (water heater system) circuit short to ground
B2452 Fuel pump (water heater system) circuit open
DETECTION
CONDITION•CPU detects malfunction in fuel pump (water heater system) circuit
POSSIBLE
CAUSE•Fuel pump (water heater system) malfunction
•Water heater unit malfunction
•Short to ground between water heater unit terminal B and fuel pump (water heater system) terminal A
•Open circuit between water heater unit terminal B and fuel pump (water heater system) terminal A
•Open circuit between fuel pump (water heater system) terminal B and GND
A C E
B D F WATER HEATER UNIT CONNECTORFUEL PUMP
(WATER HEATER SYSTEM)
CONNECTOR
A
B
STEP INSPECTION ACTION
1INSPECT WIRING HARNESS BETWEEN
WATER HEATER UNIT AND FUEL PUMP
(WATER HEATER SYSTEM) FOR
CONTINUITY
•Start the engine.
•Is the voltage at fuel pump (water heater
system) connector terminal A approximately
12 V?Yes Go to the next step
No Repair the wiring harness.
2INSPECT FUEL PUMP (WATER HEATER
SYSTEM)
•Inspect the fuel pump (water heater system).
(See U–16 FUEL PUMP (WATER HEATER
SYSTEM) INSPECTION)
•Is the fuel pump (water heater system) okay?Yes Go to the next step
No Replace the fuel pump (water heater system).
(See U–15 WATER HEATER UNIT REMOVAL/
INSTALLATION)
3INSPECT WIRING HARNESS BETWEEN
FUEL PUMP (WATER HEATER SYSTEM) AND
GROUND FOR CONTINUITY
•Is there continuity between the fuel pump
(water heater system) connector terminal B
and ground?Yes Go to the next step
No Repair the wiring harness.