Infiniti Q45 (FY33). Manual - part 154
SEF594K
Engine Coolant Temperature Sensor (ECTS)
COMPONENT DESCRIPTION
The engine coolant temperature sensor is located near the No. 2
injector. The sensor is used to detect the engine coolant tempera-
ture. The sensor modifies a voltage signal from the ECM. The
modified signal returns to the ECM as the engine coolant tempera-
ture input. The sensor uses a thermistor which is sensitive to the
change in temperature. The electrical resistance of the thermistor
decreases as temperature increases.
SEF012P
<Reference data>
Engine coolant tempera-
ture
°C (°F)
Voltage*
V
Resistance
k
Ω
−10 (14)
4.4
7.0 - 11.4
20 (68)
3.5
2.1 - 2.9
50 (122)
2.2
0.68 - 1.00
90 (194)
1.0
0.236 - 0.260
*: These data are reference values and are measured between ECM terminal
q
67
(Engine coolant temperature sensor) 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.
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code
No.
Malfunction is detected when ...
Check Items
(Possible Cause)
P0115
0103
I
An excessively high or low voltage from the sensor is
sent to ECM.*
I
Harness or connectors
(The sensor circuit is open or shorted.)
I
Engine coolant temperature sensor
*: When this malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.
Engine operating condition in fail-safe mode
Condition
Engine coolant temperature decided
(CONSULT-II DISPLAY)
Engine coolant temperature will be determined
by ECM based on the time after turning igni-
tion switch “ON” or “START”.
CONSULT-II displays the engine coolant tem-
perature decided by ECM.
Just as ignition switch is turned ON or Start
40°C (104°F)
More than 4 minutes after ignition Start
80°C (176°F)
Except as shown above
40 - 80°C (104 - 176°F)
(Depends on the time)
GI
MA
EM
LC
FE
AT
PD
FA
RA
BR
ST
RS
BT
HA
EL
IDX
TROUBLE DIAGNOSIS FOR DTC P0115
EC-145