Mazda Mazda6 Workshop Manual Supplement page 889

DTC B1318
DTC B1318 Input voltage low
DETECTION
• Voltage detected at water heater unit terminals A is less than 9 V.
CONDITION
• Generator malfunction
POSSIBLE
• Battery malfunction
CAUSE
Diagnostic procedure
STEP
1 INSPECT BATTERY VOLTAGE
• Measure the battery voltage.
• Is the voltage more than 9 V?
2 INSPECT WIRING HARNESS BETWEEN W.HEAT
40 A FUSE AND WATER HEATER UNIT
• Turn the ignition switch to the ON position.
• Measure the voltage at water heater unit
connector terminal A.
• Is the voltage more than 9 V?
3 INSPECT WATER HEATER UNIT
• Clear the DTC.
• Perform the KOEO Self Test. (See
Self Test/Combustion
• Is the same DTC present?
4 VERIFY AFTER REPAIR PROCEDURE
• Perform the after repair procedure. (See
After Repair Procedure.)
• Are any DTCs present?
End Of Sie
DTC B1342, B2463, B2537, B2538, B2547
B1342 Malfunction in water heater unit
B2463 Overheat
DTC B2537 Water heater system does not start
B2538 Unstable flame
B2547 Flame prior to operation
DETECTION
• CPU detects malfunction in water heater unit
CONDITION
• Water heater unit malfunction
POSSIBLE — CPU malfunction
CAUSE — Glow plug malfunction
— Flame detection sensor malfunction
Diagnostic procedure
STEP
1 INSPECT WATER HEATER UNIT
• Replace the water heater unit. (See
WATER HEATER UNIT REMOVAL/
INSTALLATION)
• Perform the Combustion Test. (See
Self Test/Combustion
• Are any DTCs present?
End Of Sie
ON-BOARD DIAGNOSTIC
U H EATER AND AIR CONDITIONER SYSTEMS
WATER HEATER UNIT CONNECTOR
E
F
INSPECTION
U–22 KOEO
Test.)
U–22–1
INSPECTION
U–15
U–22 KOEO
Test.)
ON-BOARD DIAGNOSTIC
C A
D B
Yes Go to the next step.
No The battery is weak.
• Inspect the charging system.
Yes Go to the next step.
No Repair the wiring harness.
Yes Replace the water heater unit.
(See U–15 WATER HEATER UNIT REMOVAL/
INSTALLATION)
No Go to the next step.
Yes Go to the applicable DTC troubleshooting.
No Troubleshooting completed.
Yes Go to the applicable DTC troubleshooting.
No Troubleshooting completed.
A6E857001038204
ACTION
A6E857001038205
ACTION
U–23
U