Mitsubishi Evolution X. Manual - part 121

SENSOR

TSB Revision

MULTIPORT FUEL SYSTEM (MFI)

13A-13

STRUCTURE AND SYSTEM

Accelerator pedal position sensor is composed of a permanent 
magnet fixed on the magnet carrier of the pedal shaft, Hall IC 
outputs voltage according to magnetic flux density and a stator 
that efficiently introduces magnetic flux from the permanent 
magnet to Hall IC.

Magnetic flux density at Hall IC is proportional to the output 
voltage. 
The accelerator pedal position sensor has 2 output systems 

− 

accelerator pedal position sensor (main) and accelerator pedal 
position sensor (sub), and the output voltage is output to ECM. 
According to depression of the accelerator pedal, output volt-
age of the accelerator pedal position sensor (main) and accel-
erator pedal position sensor (sub) changes. This allows ECM to 
detect the actual accelerator pedal depression amount. ECM 
uses accelerator pedal position sensor (main) output voltage 
for appropriate throttle valve opening angle control and fuel 
injection volume control. Also, ECM compares output voltage of 
the accelerator pedal position sensor (main) and accelerator 
pedal position sensor (sub) to check for abnormality in sensor. 
The relationship between accelerator opening angle and output 
voltage of the accelerator pedal position sensor (main) and 
accelerator pedal position sensor (sub) is as shown in the fig-
ure below.

AK602570AC

Magnet

Pedal shaft

Hall IC

AK602571

 S 

 N

 S 

 N

 N

 S

 N

 S

AC

Hall IC

Hall IC

Magnetic flux density
: minimum

Magnetic flux density
: maximum

Magnetic flux

SENSOR

TSB Revision

MULTIPORT FUEL SYSTEM (MFI)

13A-14

.

HEATED OXYGEN SENSOR

Heated oxygen sensors are installed in the front exhaust pipe 
and in the catalytic converter. Heated oxygen sensor has a 
built-in heater to help early activation of the sensor. This allows 
feedback control of air-fuel ratio soon after engine start.

.

This sensor uses the oxygen concentration cell principle of 
solid electrolyte (zirconia) and displays the property of sudden 
change in output voltage near theoretical air-fuel ratio. This 
property is used to detect oxygen density in exhaust gas. Feed-
back to ECM allows it to judge whether air-fuel ratio is rich or 
lean compared to theoretical air-fuel ratio.

AK602211

5V

5V

5

4

3

2

1

0

AE

Accelerator pedal position sensor

Accelerator pedal
position sensor (main)

Accelerator pedal
position sensor (main)

Accelerator
pedal stroke

Accelerator pedal
position sensor (sub)

Accelerator pedal
position sensor (sub)

Hall IC

Hall IC

Fully
opened

Output voltage V

ECM

AK602572 AC

Sensing area

AK602262AC

0.8

14

15

16

Theoretical air fuel ratio

Electro motive
force (V)

Rich

Lean

Air fuel ratio

SENSOR

TSB Revision

MULTIPORT FUEL SYSTEM (MFI)

13A-15

This allows ECM precise feedback control to get theoretical 
air-fuel ratio with best cleaning efficiency of 3-way catalytic con-
verter.

.

CRANKSHAFT POSITION SENSOR

A crankshaft position sensor is installed on the intake side of 
the cylinder block. The crankshaft position sensor monitors 
rotation of crankshaft sensing ring (36 teeth including 3 missing 
teeth) installed on the crankshaft and converts to voltage (pulse 
signal) that is output to ECM. ECM uses crankshaft position 
sensor's output pulse to detect crankshaft position.

.

AK602263AC

100

0

HC

CO

NOx

50

Purge ratio

Theoretical air fuel ratio

AK602576AC

From MFI relay

Heated xygen sensor

Heater

Zirconia element

ECM

0.5V

AK703135 AD

Crankshaft 
position 
sensor

Crankshaft sensing ring
(36 teeth including 3 missing teeth)

SENSOR

TSB Revision

MULTIPORT FUEL SYSTEM (MFI)

13A-16

The crankshaft position sensor uses a magnetic resistance ele-
ment. When the vane of the crankshaft-sensing ring passes the 
front surface of the magnetic resistance element, the flux from 
the magnet passes the magnetic resistance element. Thus, 
resistance of the magnetic resistance element increases. When 
the vane of the crankshaft-sensing ring does not pass the front 
surface of the magnetic resistance element, the flux from the 
magnet does not pass the magnetic resistance element and the 
resistance decreases. The crankshaft position sensor converts 
this change in resistance of the magnetic resistance element to 
a 5 V pulse signal and outputs it to ECM.

.

INTAKE CAMSHAFT POSITION SENSOR

The intake camshaft position sensor is installed on the intake 
side of the cylinder head. The intake camshaft position sensor 
monitors shape of the half-moon sensing portion and converts 
to voltage (pulse signal) that is output to ECM. Upon receiving 
this output voltage, the ECM effects feedback control to opti-
mize the phase of the intake camshaft. Also, ECM uses a com-
bination of the intake camshaft position sensor output pulse 
signal and crankshaft position sensor output pulse signal to 
identify cylinders in the compression process.

AK602265AC

Crank shaft sensing ring

Crank shaft sensing ring

Vane

Vane

Magnetic resistance element

Magnetic resistance element

Magnet flux

Magnet flux

AK602285AC

5V

5V

Crankshaft position sensor

ECM

Output signal

Magnetic resistance element

AK602738AC

Camshaft

Sensing portion

Camshaft position sensor