Infiniti Q45 (FY33). Manual — part 243
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TEC073M
GI
MA
EM
LC
FE
AT
PD
FA
RA
BR
ST
RS
BT
HA
EL
IDX
TROUBLE DIAGNOSIS FOR ECM — ABS/TCS COMM NG
ABS/TCS Communication Line (Cont’d)
EC-501
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SEF047TD
SEF641T
SEF444U
DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK INPUT SIGNAL CIRCUIT.
1. Turn ignition switch “OFF”.
2. Disconnect ECM harness connector
and ABS/TCS control unit harness con-
nector.
3. Check harness continuity between ECM
terminal
q
99
and terminal
q
16
.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
E
NG
Check the following.
I
Harness connectors
M50
,
B101
I
Harness connectors
F63
,
M49
I
Joint connector-6
I
Check harness for open
or short between ECM
and ABS/TCS control
unit.
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
Perform “TROUBLE DIAGNOSIS FOR
INTERMITTENT INCIDENT”, EC-117.
INSPECTION END
TROUBLE DIAGNOSIS FOR ECM — ABS/TCS COMM NG
ABS/TCS Communication Line (Cont’d)
H
H
H
EC-502
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Overheat
SYSTEM DESCRIPTION
Input/output signal line
Vehicle speed sensor
E
Vehicle speed
ECM
E
Cooling fan relays
Engine coolant temperature
sensor
E
Engine coolant temperature
Air conditioner switch
E
Air conditioner “ON” signal
The ECM controls the cooling fan corresponding to vehicle speed, engine coolant temperature and air condi-
tioner ON signal.
Operation
SEF751W
I
The cooling fan operates at HIGH if diagnostic test mode II (self-diagnostic results) for engine
coolant temperature sensor is “NG” or when the ECM fail-safe is activating.
I
When A/C line pressure reaches the specified value, the triple-pressure switch turns on to operate cool-
ing fans at low speed.
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Specification data are reference values.
MONITOR ITEM
CONDITION
SPECIFICATION
COOLING FAN
I
After warming up engine, idle the
engine.
I
Air conditioner switch: “OFF”
Engine coolant temperature is 94°C
(201°F) or less
OFF
Engine coolant temperature is between
95°C (203°F) and 104°C (219°F) at
vehicle speeds less than 80 km/h
HIGH
Engine coolant temperature is 105°C
(221°F) or more
HIGH
GI
MA
EM
LC
FE
AT
PD
FA
RA
BR
ST
RS
BT
HA
EL
IDX
TROUBLE DIAGNOSIS FOR OVERHEAT
EC-503
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ECM TERMINALS AND REFERENCE VALUE
Specification data are reference values, and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring voltage. Doing so may result in damage to the
ECM’s transistor. Use a ground other than ECM terminals such as the body ground.
TER-
MINAL
NO.
WIRE
COLOR
ITEM
CONDITION
DATA
(DC voltage)
34
27
LG
LG/R
Cooling fan relay-1 (High)
Cooling fan relay-2 (High)
Engine is running.
Cooling fan is not operating.
BATTERY VOLTAGE
(11 - 14V)
Engine is running.
Cooling fan is operating.
0 - 1V
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Specification data are reference values.
MONITOR ITEM
CONDITION
SPECIFICATION
AIR COND SIG
I
Engine: After warming up, idle
the engine
Air conditioner switch: “OFF”
OFF
Air conditioner switch: “ON”
(Compressor operates.)
ON
COOLING FAN
I
After warming up engine, idle the
engine.
I
Air conditioner switch: “OFF”
Engine coolant temperature is 94°C
(201°F) or less
OFF
Engine coolant temperature is
between 95°C (203°F) and 104°C
(219°F) at vehicle speed less than
20 km/h (12 MPH)
HIGH
Engine coolant temperature is
105°C (221°F) or more
ON BOARD DIAGNOSIS LOGIC
This diagnosis continuously monitors the engine coolant temperature.
If the cooling fan or another component in the cooling system malfunctions, the engine coolant temperature
will rise.
When the engine coolant temperature reaches an abnormally high temperature condition, a malfunction is
indicated.
Diagnostic trouble
code No.
Malfunction is detected when ...
Check Items
(Possible Cause)
OVERHEAT
0208
I
Engine coolant reaches an abnormally high tempera-
ture.
I
Harness or connectors.
(The cooling fan circuit is open or shorted.)
I
Cooling fan
I
Radiator hose
I
Radiator
I
Radiator cap
I
Water pump
I
Thermostat
For more information, refer to “MAIN 12
CAUSES OF OVERHEATING”, (EC-513).
CAUTION:
When a malfunction is indicated, be sure to replace the coolant following the procedure in the MA
section (“Changing Engine Coolant”, “ENGINE MAINTENANCE”). Also, replace the engine oil.
a. Fill radiator with coolant up to specified level with a filling speed of 2 liters per minute like pour-
ing coolant by kettle. Be sure to use coolant with the proper mixture ratio. Refer to MA section
(“Anti-freeze Coolant Mixture Ratio”, “RECOMMENDED FLUIDS AND LUBRICANTS”).
b. After refilling coolant, run engine to ensure that no water-flow noise is emitted.
TROUBLE DIAGNOSIS FOR OVERHEAT
Overheat (Cont’d)
EC-504
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