Isuzu KB P190. Manual - part 816

Engine Management – V6 – General Information 

Page 6C1-1–22 

 

4.6 

Clutch Pedal Switch Assembly – Manual 
Vehicles Only 

The cruise control cancel switch (1) is normally closed when 
the clutch pedal is at rest, opening when the pedal is 
pressed. Activation of this switch removes the signal to the 
ECM which will then deactivate the cruise control. For 
further information on the cruise control system, refer to  
7A1 Clutch – V6. 

Figure 6C1-1 – 19 

4.7 

Engine Control Module 

Located at the right front of the engine assembly, the engine 
control module (ECM) monitors input signals from the 
various sensors and switches connected to the engine 
management system. The ECM processes this information, 
to control the following: 

• 

fuel delivery and injection system, 

• 

throttle actuation system, 

• 

ignition system, 

• 

on-board diagnostics, 

• 

the engine cooling fan, and 

• 

the air-conditioner compressor clutch (where fitted). 

The ECM supplies 5 V to the various sensors through pull-
up resistors to the internal regulated power supplies. 

The ECM controls output circuits such as the injectors, etc. 
by applying control signal to the ground circuits of the 
components through transistors or a device inside the ECM 
called a driver. The exception to this is the fuel pump relay 
control circuit. The fuel pump relay is the only ECM 
controlled circuit where the ECM controls the 12 V sent to 
the coil of the relay. The ground side of the fuel pump relay 
coil is connected to engine ground. 

The ECM communicates directly with the various control 
units within the vehicle using the General Motors local area 
network (GM LAN) serial data communication protocol. 
Refer to 3.9 

Serial Data Communication System. 

Figure 6C1-1 – 20 

Engine Management – V6 – General Information 

Page 6C1-1–23 

 

4.8 

Engine Coolant Temperature Sensor 

The engine coolant temperature (ECT) sensor is a 
thermistor, which is a resistor that changes it’s resistance 
value based on temperature.  

Figure 6C1-1 – 21 

The ECT is mounted in the engine coolant stream and as it 
is a negative temperature coefficient (NTC) type, low engine 
coolant temperature produces a high sensor resistance 
while high engine coolant temperature causes low sensor 
resistance. 

Legend 

A Temperature 

B Resistance 

The ECM provides a 5 V reference signal to the ECT and 
monitors the return signal which enables it to calculate the 
engine temperature. 

The ECM uses this signal to make corrections to the 
operating parameters of the system based on changes in 
engine coolant temperature. 

Figure 6C1-1 – 22 

4.9 

Electric Cooling Fan 

The ECM controls the operation of the electric engine 
cooling fan. The ECM applies a pulse width modulated 
(PWM) signal to the cooling fan motor to control the fan 
speed based on current vehicle conditions. For further 
information on cooling fan operation, refer to 6B1 Engine 
Cooling – V6. 

 

Figure 6C1-1 – 23 

Engine Management – V6 – General Information 

Page 6C1-1–24 

 

4.10  Engine Oil Level and Temperature 

Sensor 

The engine oil level (EOL) and temperature sensor is a dual 
purpose sensor and is fitted in the engine sump. It combines 
a switch to signal oil level and a thermistor type temperature 
sensor to provide oil temperature signal to the ECM. 

 

Figure 6C1-1 – 24 

Engine Oil Temperature Sensor 

The engine oil temperature sensor is a negative 
temperature coefficient (NTC) type. At low engine oil 
temperature, the sensor produces a high resistance, whilst 
at high temperature the sensor produces a low resistance.

Legend 

A Temperature 

B Resistance 

The ECM provides a 5 V reference signal to the engine oil 
temperature sensor and monitors the return signal which 
enables it to calculate the engine oil temperature. 

Figure 6C1-1 – 25 

Engine Management – V6 – General Information 

Page 6C1-1–25 

 

Engine Oil Level Sensor 

The engine oil level sensor is comprised of a magnetic reed 
switch (1) contained within the sensor, a float (2) and a 
magnetic pin (3). The magnetic reed switch is a normally 
open switch, which closes when a magnet field is present. 

When the engine oil level is within specifications, the pin on 
the inside of the float is pushed up against the reed switch 
(view A). When the oil level drops and the magnetic pin 
moves away from the reed switch (view B), the switch 
contacts opens.  

The ECM provides a 5 V reference signal to the engine oil 
temperature sensor and monitors the return signal. The 
ECM only monitors the oil level signal prior to engine start-
up, and once the engine is cranking, the ECM disregards 
the oil level sensor signal. 

Figure 6C1-1 – 26 

4.11  Engine Oil Pressure Sensor 

The engine oil pressure (EOP) sensor measures engine oil 
pressure. When the EOP sensor signal is below a certain 
value, the ECM sends a serial data message to the 
powertrain interface module (PIM) requesting the PIM to 
turn on the engine oil pressure warning lamp. 

 

 

Figure 6C1-1 – 27