Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
175
23.
DTC P0110
Connection for additional air temperature sensor of air mass flowmeter is
short or open.
P0112
Temperature for additional air temperature sensor of air mass flowmeter is
too low.
P0113
Temperature for additional air temperature sensor of air mass flowmeter is
too high.
P1101
Analog output voltage for additional air temperature sensor of air mass
flowmeter is too high or too low.
P1102
Output duty ratio signal level of additional air temperature sensor of air
mass flowmeter is too high or too low.
P1106
Output duty ratio signal cycle of additional air temperature sensor of air
mass flowmeter is too long.
P1107
Output duty ratio signal cycle of additional air temperature sensor of air
mass flowmeter is too short.
Fault Description: Intake air temperature (IAT) sensor is a variable resistance for measurement of engine intake air
temperature. Air temperature sensor possesses a signal circuit and a low reference voltage circuit. ECU provides air
temperature sensor signal circuit with 5V voltage and provides air temperature sensor reference voltage circuit with
grounding. When air temperature sensor is under cold status, sensor resistance value is high. When air temperature
increases, sensor resistance value decreases. In the case of high sensor resistance, voltage of air temperature sensor
signal circuit detected by ECU is high. With decrease of sensor resistance, voltage of air temperature sensor signal
circuit detected by ECU reduces. In the case of too low detected air temperature signal voltage by ECU (it is indicated
that temperature is too high) or too high signal voltage (it is indicated that temperature is too low), DTC for this
occurs.
Differences among temperature, resistance and voltage are shown as the table below:
Temperature
Temperature Sensor Resistance
Temperature Sensor Signal Voltage
Low
High
High
High Low
Low
Diagnosis Hint: Test air temperature sensor under different temperatures for evaluation of sensor errors. In the case of
sensor error, there will be control performance fault. Lay the engine up for one night, D-value between air temperature
sensor and engine coolant temperature sensor displayed values should be within 3°C (5°F). Please refer to
“Temperature and Resistance”. In the case of too high resistance of temperature sensor signal circuit or low reference
voltage circuit, DTC may not occur.
Check for the following conditions:
Check ECU harness connector for poor contact between ECU and temperature sensor
− Terminal looseness
− Poor fit of matching parts
− Locking plate fracture
− Terminal deformation or damage
− Poor contact between terminal and wire