Page 96 - Foton Workshop Manual - Auman EST-M

DI - 42 Diagnosis - Diagnosis-fault diagnosis of electronic and electrical parts

Coolant manifold temperature sensor failure
144- circuit of engine cooling fluid temperature sensor 1-voltage above normal value or short to
high-voltage power source
145- The voltage of engine coolant temperature sensor 1 circuit is lower than the normal value or short
to the low voltage power supply

146- engine cooling fluid temperature-valid but over normal operating range-medium severity level
151- engine cooling fluid temperature-valid but over normal operating range-the highest severity level
Overview

1. Coolant temperature sensor is used to measure the engine coolant temperature, so that the ECM determines
the engine operating conditions in order to control the fuel injection.
2. The coolant temperature sensor controls the coolant temperature through the negative temperature
coefficient thermistor. Temperature higher, resistance smaller This resistance is a part of bleeder circuit which
is applied with 5V voltage Measure the voltage on the resistance changing according to the temperature. Each
voltage corresponds with a temperature on the ECM internal characteristic curve.
Circuit diagram

Engine ECM

Cooling temperature signal Sensor grounding

White- yellow Black

Coolant temperature sensor

DI-042