Dtc211 - Fuel Temperature Sensor System Fault - Isuzu 4HL1 Workshop Manual

1A-190 Engine Control System

DTC211 - Fuel Temperature Sensor System Fault

Circuit Description
The FT (fuel temperature) sensor consists of thermistor
and alters the resistance in response to temperature
change. Higher fuel temperature provides smaller
resistance while lower temperature provides larger
resistance. The ECM supplies 5 V to the FT sensor via
pull-up resistance and calculates the fuel temperature
from the change in voltage and uses it in supply pump
control and other control tasks. The voltage is
decreased when the
temperature is high) while increased when the
resistance is large (the temperature is low).
DTC211 will be set when the signal voltage is
excessively high or low.
Major Faulty Event
• Poor driveability
Conditions for Setting the DTC
The FT sensor output voltage deviates from the range
between 0.1 V and 4.8 V for at least 1 seconds.
Action Taken When the DTC Sets
• Even after the DTC is set, the ECM will not
illuminate the CHECK ENGINE lamp (MIL).
• The ECM controls the powertrain using the set fuel
temperature (normal running phase: 70°C, startup
phase: –20°C).
49 46
ECT
Sensor
resistance is small
ECM
(Engine
Control
Module)
48
FT
Sensor
Conditions for Clearing MIL/DTC
When the system fails and the DTC is stored to the
ECM, even repairing the faulty portion will not clear the
DTC from the memory. To clear the DTC, conduct the
following steps.
1. Turn off the idle position switch for not less than 1
second but not more than 3 seconds. (Press the
accelerator pedal.)
2. Turn on the idle position switch for not less than 1
(the
second but not more than 3 seconds. (Release the
accelerator pedal.)
3. Turn off the idle position switch for not less than 1
second but not more than 3 seconds. (Press the
accelerator pedal.)
4. Turn on the idle position switch for not less than 1
second but not more than 3 seconds. (Release the
accelerator pedal.)
5. Turn off the idle position switch for not less than 1
second but not more than 3 seconds. (Press the
accelerator pedal.)
6. After the above operations are properly completed,
the CHECK ENGINE lamp (MIL) illuminates for 3
seconds to report the memory is cleared.
7. Turn off the starter switch. Wait for 5 seconds and
turn on the starter switch again.
When Tech 2 has been connected to the vehicle, the
DTC can be cleared through the memory clear
operation with Tech 2.
LNW21AMF007101-X