turn signal MITSUBISHI TRITON 1997 Workshop Manual

ENGINE <4G6> ± On-vehicle Service11A-11
16. Attach a sealing tape to the fixing bolt and nut only for
vehicles for Switzerland.
NOTE
Sealing tape is attached to all new vehicles.
IDLE SPEED CHECK11100190330
1. Before inspection, set the vehicle to the pre-inspection
condition.
2. Check the basic ignition timing. Adjust if necessary.
Standard value: 5 BTDC+2
3. After turning the ignition switch to OFF, connect the MUT-II
to the diagnosis connector.
4. Start the engine and run it at idle.
5. Run the engine at idle for 2 minutes.
6. Check the idle speed.
Curb idle speed: 750+100 r/min
NOTE
The idle speed is controlled automatically by the idle speed
control (ISC) system.
7. If the idle speed is outside the standard value, inspect
the MPI components by referring to GROUP 13A ±
Troubleshooting.
IDLE MIXTURE CHECK11100210265
1. Before inspection, set the vehicle to the pre-inspection
condition.
2. Check that the basic ignition timing is within the standard
value.
Standard value: 5 BTDC+2
3. Turn the ignition switch to OFF and connect the MUT-II
to the diagnosis connector.
4. Start the engine and run it at 2,500 r/min for 2 minutes.
5. Set the CO, HC tester.
6. Check the CO contents and the HC contents at idle.
Standard value:
CO contents: 0.5% or less
HC contents: 100 ppm or less
7. If there is a deviation from the standard value, check
the following items:

Diagnosis output

Closed-loop control (When the closed-loop control
is normal, the output signal of the oxygen sensor
changes between 0 ± 400 mV and 600 ± 1,000 mV
at idle.)

MPI ± General Information13A-3
MULTIPOINT FUEL INJECTION (MPI)13100010265
GENERAL INFORMATION
The Multipoint Fuel Injection System consists
of sensors which detect the engine conditions,
the engine-ECU which controls the system
based on signals from these sensors, and
actuators which operate under the control of
the engine-ECU. The engine-ECU carries outactivities such as fuel injection control, idle
speed control and ignition timing control. In
addition, the engine-ECU is equipped with
several diagnosis modes which simplify
troubleshooting when a problem develops.
FUEL INJECTION CONTROL
The injector drive times and injector timing are
controlled so that the optimum air/fuel mixture
is supplied to the engine to correspond to the
continually-changing engine operation condi-
tions.
A single injector is mounted at the intake port
of each cylinder. Fuel is sent under pressure
from the fuel tank by the fuel pump, with the
pressure being regulated by the fuel pressure
regulator. The fuel thus regulated is distributed
to each of the injectors.
Fuel injection is normally carried out once for
each 2-cylinder group for every two rotationsof the crankshaft. This is called group fuel
injection. The engine-ECU provides a richer
air/fuel mixture by carrying out ªopen-loopº
control when the engine is cold or operating
under high load conditions in order to maintain
engine performance. In addition, when the
engine is warm or operating under normal
conditions, the engine-ECU controls the air/fuel
mixture by using the oxygen sensor signal to
carry out ªclosed-loopº control in order to obtain
the theoretical air/fuel mixture ratio that
provides the maximum cleaning performance
from the three way catalyst.
IDLE AIR CONTROL
The idle speed is kept at the optimum speed
by controlling the amount of air that bypasses
the throttle valve in accordance with changes
in idling conditions and engine load during
idling. The engine-ECU drives the idle speed
control (ISC) motor to keep the engine running
at the pre-set idle target speed in accordance
with the engine coolant temperature and airconditioner load. In addition, when the air
conditioner switch is turned off and on while
the engine is idling, the ISC motor operates
to adjust the throttle valve bypass air amount
in accordance with the engine load conditions
in order to avoid fluctuations in the engine
speed.
IGNITION TIMING CONTROL
The power transistor located in the ignition
primary circuit turns ON and OFF to control
the primary current flow to the ignition coil. This
controls the ignition timing in order to provide
the optimum ignition timing with respect to theengine operating conditions. The ignition timing
is determined by the engine-ECU from the
engine speed, intake air volume, engine coolant
temperature and atmospheric pressure.
SELF-DIAGNOSIS FUNCTION

When an abnormality is detected in one
of the sensors or actuators related to
emission control, the engine warning lamp
(check engine lamp) illuminates as a
warning to the driver.

When an abnormality is detected in one
of the sensors or actuators, a diagnosiscode corresponding to the abnormality is
output.

The RAM data inside the ENGINE-ECU
that is related to the sensors and actuators
can be read by means of the MUT-II. In
addition, the actuators can be force-driven
under certain circumstances.

MPI ± Troubleshooting13A-9
Engine warning lamp inspection items
Engine-ECU
Oxygen sensor
Air flow sensor
Intake air temperature sensor
Throttle position sensor
Engine coolant temperature sensor
Crank angle sensor
Top dead centre sensor
Barometric pressure sensor
Ignition timing adjustment signal
Injector
Immobilizer system
Caution
Engine warning lamp will come on even when terminal
for ignition timing adjustment is short-circuited.
Therefore, it is not abnormal that the lamp comes
on even when terminal for ignition timing adjustment
is short-circuited at the time of ignition timing
adjustment.
METHOD OF READING AND ERASING DIAGNOSIS
CODES
Refer to GROUP 00 ± How to Use Troubleshooting/Inspection
Service Points.
INSPECTION USING MUT-II DATA LIST AND
ACTUATOR TESTING
1. Carry out inspection by means of the data list and the
actuator test function.
If there is an abnormality, check and repair the chassis
harnesses and components.
2. After repairing, re-check using the MUT-II and check that
the abnormal input and output have returned to normal
as a result of the repairs.
3. Erase the diagnosis code memory.
4. Remove the MUT-II.
5. Start the engine again and carry out a road test to confirm
that the problem has disappeared.

MPI ± Troubleshooting13A-10
FAIL-SAFE FUNCTION REFERENCE TABLE13100910190
When the main sensor malfunctions are detected by the diagnosis function, the vehicle is controlled
by means of the pre-set control logic to maintain safe conditions for driving.
Malfunctioning itemControl contents during malfunction
Air flow sensor1. Uses the throttle position sensor signal and engine speed signal (crank angle sensor
signal) to take reading of the basic injector drive time and basic ignition timing from
the pre-set mapping.
2. Fixes the ISC servo in the appointed position so idle control is not performed.
Intake air temperature
sensorControls as if the intake air temperature is 25
C.
Throttle position
sensor (TPS)No increase in fuel injection amount during acceleration due to the throttle position sensor
signal.
Engine coolant
temperature sensorControls as if the engine coolant temperature is 80
C.
Top dead centre
sensorInjects fuel to all cylinders simultaneously.
(However, after the ignition switch is turned to ON, the No. 1 cylinder top dead centre is not
detected at all.)
Barometric pressure
sensorControls as if the barometric pressure is 101 kPa.
Oxygen sensorAir/fuel ratio feedback control (closed loop control) is not performed.
INSPECTION CHART FOR DIAGNOSIS CODES13100870214
Code No.Diagnosis itemReference page
11Oxygen sensor system13A-11
12Air flow sensor system13A-12
13Intake air temperature sensor system13A-12
14Throttle position sensor system13A-13
21Engine coolant temperature sensor system13A-14
22Crank angle sensor system13A-15
23Top dead centre sensor system13A-16
24Vehicle speed sensor system13A-17
25Barometric pressure sensor system13A-18
36*Ignition timing adjustment signal system13A-19
41Injector system13A-19
54Immobilizer system13A-20
NOTE
*: Malfunction code No. 36 is not memorized.

MPI ± Troubleshooting13A-13
Code No. 14 Throttle position sensor systemProbable cause
Range of Check

Ignition switch: ON

Excluding 60 seconds after the ignition switch is turned to ON or immediately
after the engine starts.
Set conditions

When the idle position switch is ON, the sensor output voltage is 2 V or more
for 4 seconds.
or

The sensor output voltage is 0.2 V or less for 4 seconds.
Malfunction of the throttle position sensor or
maladjustment

Improper connector contact, open circuit or
short-circuited harness wire of the throttle position
sensor circuit

Improper ªONº state of idle position switch

Short circuit of the idle position switch signal line

Malfunction of the engine-ECU
MUT-II Data list
26 Idle position switch system
OK:With the throttle valve at the
idle position: ON
With the throttle valve slight-
ly open: OFFNGCheck the idle position switch system.
(Refer to P.13A-40 INSPECTION
PROCEDURE 25.)
OK
Check the throttle position sensor.
(Refer to P.13A-87.)NG
Replace
OK
Measure at the throttle position sensor
connector A-47.

Disconnect the connector, and
measure at the harness side.

Voltage between 4 and earth
(Ignition switch: ON)
OK:4.8 ± 5.2 V

Continuity between 1 and earth
OK:ContinuityNGCheck the following connector.
C-51NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between the
engine-ECU and the throttle position
sensor connector.NG
Repair
OK
Replace the engine-ECU. OK
Check the throttle position sensor out-
put circuit. (Refer to P.13A-55, IN-
SPECTION PROCEDURE 46.)

MPI ± Troubleshooting13A-17
Code No. 24 Vehicles speed sensor systemProbable cause
Range of check

Ignition switch: ON

Excluding 60 seconds after the ignition switch is turned to ON or immediately
after the engine starts.

Idle position switch: OFF

Engine speed is 3,000 r/min or more.

Driving under high engine load conditions.
Set conditions

Sensor output voltage does not change for 4 seconds (no pulse signal input).
Malfunction of the vehicle speed sensor

Improper connector contact, open circuit or
short-circuited harness wire of the vehicle speed
sensor circuit

Malfunction of the engine-ECU
Check the vehicle speed sensor. (Refer to GROUP 54 ± Combina-
tion Meters.)NG
Replace
OK
Measure at the combination meter connector C-06, C-07.

Disconnect the connector and measure st the harness side.
1. Voltage between 51 and earth (Ignition switch: ON)
OK: 4.8 ± 5.2 V
2. Continuity between 34 and earth
OK: Continuity1. NGCheck the following
connectors.
C-19, C-51NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between the engine-ECU
and the combination me-
ter connector.NG
Repair
OK
Replace the engine-ECU.
2. NG
Check the harness wire between the combination meter and the
earth, and repair if necessary.
OK
Check the following
connectors.
C-06, C-07, C-19NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between the engine-ECU
and the combination me-
ter connector.NG
Repair
OK
Replace the engine-ECU.

MPI ± Troubleshooting13A-39
INSPECTION PROCEDURE 23
Power supply system and ignition switch-IG system
Probable cause
When an ignition switch ON signal is input to the engine-ECU, the engine-ECU turns
the control relay ON. This causes battery voltage to be supplied to the engine-ECU,
injectors and air flow sensor.
Malfunction of the ignition switch

Malfunction of the control relay

Improper connector contact, open circuit or
short-circuited harness wire

Disconnected engine-ECU earth wire

Malfunction of the engine-ECU
Check the control relay. (Refer to P.13A-86.)NG
Replace
OK
Measure at the control relay connector C-53.

Disconnect the connector, and measure at the harness side.

Voltage between 3, 4 and earth
OK:System voltageNGCheck the harness wire between battery and control relay connector,
and repair if necessary.
OK
Check the engine-ECU power supply and earth circuit.
(Refer to P.13A-53, INSPECTION PROCEDURE 42.)

MPI ± Troubleshooting13A-43
INSPECTION PROCEDURE 28
Power steering fluid pressure switch system
Probable cause
The presence or absence of power steering load is input to the engine-ECU.
The engine-ECU controls the idle speed control (ISC) servo based on this input.
Malfunction of power steering fluid pressure switch

Improper connector contact, open circuit or
short-circuited harness wire

Malfunction of the engine-ECU
Check the power steering fluid pressure switch.
(Refer to GROUP 37A ± On-vehicle Service.)NG
Replace
OK
Measure at the power steering fluid pressure switch connector
A-74.

Disconnect the connector, and measure at the harness side.

Voltage between 1 and earth (Ignition switch: ON)
OK:System voltageNGCheck the following
connector. C-50NG
Repair
OK
Check trouble symptom.
NG
Check harness wire be-
tween engine-ECU and
power steering fluid pres-
sure switch connector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following
connector. A-74NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
INSPECTION PROCEDURE 29
A/C switch and A/C relay system
Probable cause
When an A/C ON signal is input to the engine-ECU, the engine-ECU carries out
control of the idle speed control (ISC) servo, and also operates the A/C compressor
magnetic clutch.
Malfunction of A/C control system

Malfunction of A/C switch

Improper connector contact, open circuit or
short-circuited harness wire

Malfunction of the engine-ECU
Check the A/C compressor relay.
(Refer to GROUP 55 ± On-vehicle Service.)NG
Replace
OK
Measure at the engine-ECU connectors C-49, C-50.

Disconnect the connector, and measure at the harness side.


Voltage between 22 and earth, and 45 and earth
(Ignition switch: ON, A/C switch: ON)
OK:System voltage

Short circuit between 22 and earth
(Ignition switch: ON, A/C switch: ON)
OK:A/C compressor clutch turns on.


Voltage between 8 and earth, and 45 and earth
(Ignition switch: ON, A/C switch: ON)
OK:System voltage

Short circuit between 8 and earth
(Ignition switch: ON, A/C switch: ON)
OK:A/C compressor clutch turns on.NGCheck the A/C system. (Refer to GROUP 55 ± On-vehicle Service.)
OKCheck the following
connectors. C-49, C-50NG
Replace
OK
Check trouble symptom.
NG
Replace the engine-ECU.

MPI ± Troubleshooting13A-57
DATA LIST REFERENCE TABLE13100890180
Caution
When shifting the select lever to D range, the brakes should be applied so that the vehicle does
not move forward.
NOTE
*1. In a new vehicle [driven approximately 500 km or less], the air flow sensor output frequency is sometimes
10% higher than the standard frequency.
*
2. The idle position switch normally turns off when the voltage of the throttle position sensor is 50 ±
100 mV higher than the voltage at the idle position. If the idle position switch turns back on after
the throttle position sensor voltage has been by 100 mV and the throttle valve has been opened,
the idle position switch and the throttle position sensor need to be adjusted.
*3. The injector drive time represents the time when the cranking speed is at 250 r/min or below when
the power supply voltage is 11 V.
*4. In a new vehicle [driven approximately 500 km or less], the injector drive time is sometimes 10%
longer than the standard time.
*5. In a new vehicle [driven approximately 500 km or less], the step of the stepper motor is sometimes
30 steps greater than the standard value.
Item
No.Inspection
itemInspection contentsNormal conditionInspection
procedure
No.Reference
page
11Oxygen
sensorEngine:After having
warmed up
Air/fuel mixture is
made leaner when de-
When at 4,000 r/min,
engine is suddenly
decelerated200 mV or lessCode No.
1113A-11
made leaner when de-
celerating, and is made
richer when racing.
When engine is
suddenly raced600 ± 1,000 mV
Engine:After having
warmed up
The oxygen sensor
signal is used to check
the air/fuel mixture
ratio and control
Engine is idling400 mV or less
(Changes)
600 ± 1,000 mV
ratio, and control
condition by the en-
gine-ECU.2,500 r/min400 mV or less
(Changes)
600 ± 1,000 mV
12Air flow
sensor*1
Engine coolant
temperature:
80 ± 95C

Lamps and all
accessories: OFF
Engine is idling22 ± 48 Hz
<4G63>
19 ± 45 Hz
<4G64>±±
accessories: OFF

Transmission:
Neutral (A/T:
P range)2,500 r/min80 ± 120 Hz
<4G63>
67 ± 107 Hz
<4G64>
Engine is racedFrequency
increases in
response to
racing

AUTOMATIC TRANSMISSION ± Troubleshooting23-6
Ye s
Carry out TEST 4 again.
Ye s
Does the engine brake function in L range?NoBrake No. 3 malfunction
No
Does the engine brake function in 2 range?NoBrake No. 1 malfunction
TEST 4
When traveling in 3-speed or 4-speed, shift to 2 and L. Does the
engine brake function in each range?Ye sTEST 5
Ye s

High line pressure

Accumulator malfunction

Check ball malfunctionCarry out TEST 5 again.
TEST 5
Is there abnormal noise(s) during acceleration and deceleration?
Is there shocks when slipping and changing speed?NoTEST 6
Ye s

Incorrect torque converter installation

Oil pump malfunction

Shifting gear not meshing correctly

Incorrect drive plate installationCarry out TEST 6 again.
TEST 6
Is there abnormal noise(s) or vibration when traveling in 3-speed
or 4-speed?NoTEST 7
NOTE
Abnormal noises and vibrations are often caused by an unbalanced propeller shaft, differential, tyre,
torque converter, engine, etc. Extremely thorough inspection is therefore required.
Ye s
Carry out TEST 7 again.
Ye s
Does lock up go on, off?No
Lock up signal valve malfunction

Lock up relay valve malfunction

Lock up clutch malfunction
No
Does the moment when lock up turns ON or OFF conform with
the shift pattern?No
Governor malfunction

Line pressure malfunction
TEST 7
Check that lock up ON, OFF. Does the shifting points conform
with shift pattern?Ye sCarry out the road test in 2 range.
NOTE
(1) Determine the moment when lock up turns ON by decreased engine r/min or by a slight shock back
and forth.
(2) Determine the moment when lock up turns OFF by increased engine r/min.
(3) Check lock up condition by pumping the accelerator slightly. If engine r/min rises in accordance with
throttle valve opening size, determine that the lock up is OFF, if not, determine it ON.
(When lock up is OFF, drive power is transferred through the fluid in the torque converter and therefore,
when the accelerator pedal is depressed, slipping occurs inside the torque converter with a resulting
large increase in engine r/min.)