Mitsubishi Eclipse. Manual - part 361

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-937

Check using oscilloscope
1. Disconnect the throttle position sensor connector and 

connect the test harness special tool (MB991348) in 
between.(All terminals should be connected.)

2. Connect the oscilloscope probe to the throttle position 

sensor side connector terminal No. 3.

3. Turn the ignition switch "ON" position.
4. Slowly move the throttle lever from the idle position to the 

full-throttle position and check then if the waveform is free 
from any noise.

5. If any noise is recognized, replace the throttle position 

sensor.
NOTE: After replacement, the throttle position sensor should 
be adjusted. (Refer to 

P.13A-927

.)

HEATED OXYGEN SENSOR CHECK

M1131005000624

Required Special Tools:

• MB991958 (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

• MB991658: Test Harness Set

• MD998464: Test Harness

.

AK102987AB

1 2 3 4

THROTTLE POSITION
SENSOR CONNECTOR

OSCILLOSCOPE

MB991348

AKX01462AB

NORMAL WAVEFORM

THROTTLE LEVER
FULL-THROTTLE
POSITION

THROTTLE
LEVER
IDLE
POSITION

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-938

<Heated oxygen sensor (front)>
1. Using the scan tool MB991958, observe HO

2

S reading. If 

values are unsatisfactory, or if Scan tool is not available, use 
the following procedure:

(1) Disconnect the heated oxygen sensor connector and 

connect special tool MD998464 to the connector on the 
heated oxygen sensor side.

(2) Make sure that there is continuity [4.5 

− 8.0 ohms at 20°C 

(68

°F)] between terminal No. 1 (red clip of special tool) 

and terminal No. 3 (blue clip of special tool) on the heated 
oxygen sensor connector

(3) If there is no continuity, replace the heated oxygen 

sensor.

(4) Warm up the engine until engine coolant is 80

°C (176°F) 

or higher.

(5) Perform a tracing for 5 minutes or more with the engine 

speed of 4,500 r/min.

(6) Connect a digital voltage meter between terminal No. 2 

(black clip of special tool) and terminal No. 4 (white clip of 
special tool).

2. While repeatedly revving the engine, measure the heated 

oxygen sensor output voltage.

Standard value:

CAUTION

• Be very careful when connecting the jumper wire; 

incorrect connection can damage the oxygen sensor.

• Be careful the heater is broken when voltage of beyond 

8volts is applied to the oxygen sensor heater.

NOTE: If the sufficiently high temperature (of approximate 
400

°

C or more) is not reached although the oxygen sensor is 

normal, the output voltage would be possibly low although the 
rich air-fuel ratio. Therefore, if the output voltage is low, use a 
jumper wire to connect the terminal No.1 (red clip of special 
tool) and the terminal No. 3 (blue clip of special tool) of the oxy-
gen sensor with a (+) terminal and (-) terminal of 8 volts power 
supply respectively, then check again.
3. If the sensor is defective, replace the heated oxygen sensor.
NOTE: For removal and installation of the heated oxygen sen-
sor, refer to GROUP 15, Exhaust Pipe and Main Muffler 

P.15-22

.

.

ENGINE

HEATED OXYGEN 
SENSOR OUTPUT 
VOLTAGE

REMARKS

When 
revving 
engine

0.6 

− 1.0 volt

If you make the air/fuel 
ratio rich by revving the 
engine repeatedly, a 
normal heated oxygen 
sensor will output a 
voltage of 0.6 

− 1.0 volt

AKX01624

HEATED
OXYGEN
SENSOR
EQUIPMENT
SIDE
CONNECTOR

MD998464

BLUE

RED

AC

AKX01624

HEATED
OXYGEN
SENSOR
COMPONENT
SIDE
CONNECTOR

MD998464

WHITE

BLACK

AL

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-939

<Heated oxygen sensor (rear)>
1. Using scan tool MB991958, observe HO

2

S reading. If 

values are unsatisfactory, or if Scan tool is not available, use 
the following procedure:

(1) Disconnect the heated oxygen sensor connector and 

connect special tool MB991658 to the connector on the 
heated oxygen sensor side.

(2) Make sure that there is continuity [11 

− 18 ohms at 20°C 

(68

° F)] between terminal No. 5 and terminal No. 6 on the 

heated oxygen sensor connector

(3) If there is no continuity, replace the heated oxygen 

sensor.

(4) Warm up the engine until engine coolant is 80

°C (176°F) 

or higher.

(5) Perform a tracing for 5 minutes or more with the engine 

speed of 4,500 r/min.

(6) Connect a digital voltage meter between terminal No. 3 

and terminal No. 4.

2. While repeatedly revving the engine, measure the heated 

oxygen sensor output voltage.

Standard value:

CAUTION

• Be very careful when connecting the jumper wire; 

incorrect connection can damage the oxygen sensor.

• Be careful the heater is broken when voltage of beyond 

8volts is applied to the oxygen sensor heater.

NOTE: If the sufficiently high temperature (of approximate 
400

°

C or more) is not reached although the oxygen sensor is 

normal, the output voltage would be possibly low although the 
rich air-fuel ratio. Therefore, if the output voltage is low, use a 
jumper wire to connect the terminal No.2 and the terminal No. 1 
of the oxygen sensor with a (+) terminal and (-) terminal of 8 
volts power supply respectively, then check again.
3. If the sensor is defective, replace the heated oxygen sensor.
NOTE: For removal and installation of the heated oxygen sen-
sor, refer to GROUP 15, Exhaust Pipe and Main Muffler 

P.15-22

.

ENGINE

HEATED OXYGEN 
SENSOR OUTPUT 
VOLTAGE

REMARKS

When 
revving 
engine

0.6 

− 1.0 volt

If you make the air/fuel 
ratio rich by revving the 
engine repeatedly, a 
normal heated oxygen 
sensor will output a 
voltage of 0.6 

− 1.0 volt.

AK000121AB

HEATED OXYGEN SENSOR
EQUIPMENT SIDE CONNECTOR

MB991658

AK301461

HEATED OXYGEN SENSOR

AB

MB991658

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-940

INJECTOR CHECK

M1131005200446

Measurement of Resistance between Terminals

1. Disconnect the injector connector.
2. Measure resistance between terminals.

Standard value: 13 

− 16 ohms [at 20°C (68°F)]

3. If not within specification, replace the injector.
4. Install the injector connector

Checking operation sound

Using a stethoscope or long blade screwdriver, check the oper-
ation sound ("tick-tick-tick") of injectors during idling or during 
cranking. Check that as the engine speed increases, the fre-
quency of the operating sound also increases.
1. If the injector you are checking is not operating, you may 

hear the operating sound of the other injectors.

2. If no operating sound is heard from the injector that is being 

checked, check the injector drive circuit. If there is nothing 
wrong with the circuit, a defective injector or engine control 
module (ECM) <M/T> or powertrain control module (PCM) 
<A/T> is suspected.

IDLE AIR CONTROL MOTOR (STEPPER MOTOR) 
CHECK

M1131005400525

Required Special Tool:

• MB991709: Test Harness Set

.

Checking the Operation Sound
1. Check that the engine coolant temperature is 20

°C (68°F) or 

below.
NOTE: If necessary, you can disconnect the engine coolant 
temperature sensor connector and connect the harness-side 
of the connector to another engine coolant temperature sen-
sor that is at 20

°

C (68

°

F) or below.

2. Check that the operation sound of the stepper motor can be 

heard after the ignition is switched ON (but do not start the 
engine).

3. If the operation sound cannot be heard, check the stepper 

motor's activation circuit. If the circuit is normal, it is 
probable that there is a malfunction of the stepper motor or 
engine control module (ECM) <M/T> or powertrain control 
module (PCM) <A/T>.

.

AK000602AB

1 2

AK000124 AB

STETHOSCOPE