160 KENR9126
Troubleshooting Section
This procedure covers open circuit diagnostic codes
and short circu
it diagnostic codes that are associated
with the following sensors:
•
Coolant tempe
rature sensor
•
Intake manifold air temperature sensor
•
Fuel temperature sensor
•
Transmissi
on oil temperature sensor
Use this procedure to troubleshoot the system when
one of the fo
llowing diagnostic codes is an active
diagnostic code or a recently logged diagnostic code
or when a diagnostic code can easily be activated.
•
0110-03 Engine Coolant Temperature Sensor
voltage above normal
•
0110-04 Engine Coolant Temperature Sensor
voltage below normal
•
0174-03 Fuel Temperature Sensor voltage above
normal
•
0174-04 Fuel Temperature Sensor voltage below
normal
•
0177-03 Transmission Oil Temperature Sensor
voltage above normal
•
0177-04 Transmission Oil Temperature Sensor
voltage below normal
•
0172-03 Intake Manifold Air Temperature Sensor
voltage above normal
•
0172-04 Intake Manifold Air Temperature Sensor
voltage below normal
The following background information is related
to this procedure:
The troubleshooting procedures for the diagnostic
codes of each temperature sensor are identical.
The t
emperature sensors are sensors that have
two terminals. P2:37 on the Electronic Control
Module (ECM) is the common connection for the
eng
ine temperature sensors. The sensor common
connection is shared between the temperature
sensors. The common line is connected to terminal 2
on e
ach sensor connector. Terminal 1 is the sensor
output. The signal voltage from terminal 1 of each
sensor is supplied to the appropriate terminal at ECM
Co
nnector P2/J2.
Pull-up Voltage
The ECM continuously outputs a pull-up voltage on
the circuit for
the sensor signal wire. The ECM uses
this pull-up voltage in order to detect an open in the
signal circuit. When the ECM detects the presence
of a voltage th
at is above a threshold on the signal
circuit, the ECM will generate an open circuit FMI
code (-03) for the sensor.
If the sensor is disconnected at the sensor connector,
the presence of pull-up voltage at the sensor
connector i
ndicates that the wires from the sensor
connector to the ECM are not open or shorted to
ground. If the sensor is disconnected at the sensor
connector,
the absence of pull-up voltage at the
sensor connector indicates an open in the signal wire
or a short to ground. If the sensor is disconnected at
the sensor
connector and the voltage at the sensor
connector is different from pull-up voltage, the signal
wire is shorted to another wire in the harness.
To Next Page
