1997 MITSUBISHI TRITON check engine

MPI ± Troubleshooting13A-56
INSPECTION PROCEDURE 48
Check ignition coil and power transistor unit circuit.
Check the ignition coil. (Refer to GROUP 16 ± Ignition System.)NG
Replace
OK
Check the power transistor unit.
(Refer to GROUP 16 ± Ignition System.)NG
Replace
OK
Measure at the power transistor unit connector A-70.

Disconnect the connector and measure at the harness side.
1. Voltage between 3 and earth (Ignition switch: ON)
OK: System voltage
2. Voltage between 1 and earth (Engine: Cranking)
OK: 2 ± 7 V1. OKCheck the following
connector. A-65NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between the engine-ECU
and the power transistor
unit, and repair if neces-
sary.NG
Repair
NG
As short circuit occurs between power transistor unit and combina-
tion meter (tachometer), check the harness wire, and repair if neces-
sary.
OK
Check the following connectors, and repair if necessary.
A-65, A-70NG
Check the harness wire between the power transistor unit and
ignition coil connector, and repair if necessary. 2. NG
Check the following
connector. C-49NG
Repair
OK
Check trouble symptom. OK
Measure at the power transistor unit connector A-70.

Disconnect the connector and measure at the harness side.

Disconnect the ignition coil connector.

Continuity between 3 and earth
OK: No continuity
OK
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

MPI ± Troubleshooting13A-59
Item
No.Reference
page Inspection
procedure
No. Normal condition Inspection contents Inspection
item
22Crank angle
sensor
Engine: Cranking

Tachometer:
ConnectedCompare the engine
speed readings on
the tachometer and
the MUT-II.AccordCode No.
2213A-15

Engine: Idling

Idle position
switch: ONWhen engine
coolant temperature
is ±20C1,275 ± 1,475 r/min
When engine
coolant temperature
is 0C1,225 ± 1,425 r/min
When engine
coolant temperature
is 20C1,100 ± 1,300 r/min
When engine
coolant temperature
is 40C950 ± 1,150 r/min
When engine
coolant temperature
is 80C650 ± 850 r/min
25Barometric
p
ressure
Ignition switch: ONAt altitude of 0 m101 kPaCode No.
25
13A-18
ressure
sensorAt altitude of 600 m95 kPa
25
At altitude of 1,200 m88 kPa
At altitude of 1,800 m81 kPa
26Idle position
switchIgnition switch: ON
Check by operating
acceleratorpedal
Throttle valve:
Set to idle positionONProcedure
No. 2513A-40
accelerator pedal
repeatedlyThrottle valve:
Slightly openOFF*2
27Power
steering fluid
p
ressure
Engine: IdlingSteering wheel
stationaryOFFProcedure
No. 2813A-43
pressure
switchSteering wheel
turningON

MPI ± Troubleshooting13A-60
Item
No.Reference
page Inspection
procedure
No. Normal condition Inspection contents Inspection
item
28A/C switchEngine: Idling
(when A/C switch isA/C switch: OFFOFFProcedure
No. 2913A-43
(
ON, A/C compressor
should be operating.)A/C switch: ONON
29Inhibitor
switch
Ignition switch: ONP or NP or NProcedure
No 27
13A-42
switch
D, 2, L or RD, 2, L or R
No. 27
41Injectors *3Engine: CrankingWhen engine cool-
ant temperature is
0C51 ± 76 ms
<4G63>
60 ± 90 ms
<4G64>±±
When engine
coolant temperature
is 20C26 ± 38 ms
<4G63>
30 ± 45 ms
<4G64>
When engine
coolant temperature
is 80C5.7 ± 8.5 ms
<4G63>
6.7 ± 10.1 ms
<4G64>
Injectors*4
Engine coolant
temperature:
80 ± 95C

Lamps and all
accessories: OFF
Engine is idling1.9 ± 3.1 ms
<4G63>
2.2 ± 3.4 ms
<4G64>
accessories: OFF

Transmission:
Neutral (A/T :
P range)2,500 r/min1.8 ± 3.0 ms
<4G63>
1.9 ± 3.1 ms
<4G64>
When engine is
suddenly racedIncreases
44Ignition coils
and power
Engine: After
having warmed upEngine is idling2±18BTDC±±
transistors
g

Timing lamp is set.
(The timing lamp
is set in order to
check actual
ignition timing.)2,500 r/min23 ± 43 BTDC
<4G63>
27 ± 47 BTDC
<4G64>

MPI ± Troubleshooting13A-62
ACTUATOR TEST REFERENCE TABLE13100900210
Item
No.Inspection
itemDrive contentsInspection contentsNormal conditionInspection
procedure
No.Reference
page
01InjectorsCut fuel to No.1,
No.3 injectorEngine:
After having warmed up/En-
gine is idling
(Cut the fuel supply to each
Idling condition
becomes different
(becomes unsta-
ble)
Code No.
4113A-19
02Cut fuel to No.2,
No.4 injector(Cut the fuel supply to each
injector in turn and check
cylinders which don't affect
idling.)
ble).
07Fuel pumpFuel pump
operates and
fuel is recircu-
lated.
Engine:
Cranking

Fuel
pump:
Forced
driving
Inspect
accord-
Pinch the
return hose
with fingers
to feel the
pulse of the
fuel being
recirculated.Pulse is felt.Procedure
No. 2413A-40
accord-
ing to
both the
above
condi-
tions.
Listen near
the fuel tank
for the
sound of fuel
pump
operation.Sound of operation
is heard.
08Purge
control
solenoid
valveSolenoid valve
turns from OFF
to ON.Ignition switch: ONSound of operation
can be heard when
solenoid valve is
driven.Procedure
No. 3213A-45
10EGR
control
solenoid
valveSolenoid valve
turns from OFF
to ON.Ignition switch: ONSound of operation
can be heard when
solenoid valve is
driven.Procedure
No. 3313A-46

MPI ± Troubleshooting13A-65
Terminal No.Normal condition Check condition (Engine condition) Check item
35Oxygen sensor heaterEngine: Idling after warming up0±3V
Engine r/min: 5,000r/min.System voltage
36Engine warning lampIgnition switch: OFF
ON0 ± 3V
9 ± 13V
(After several seconds have
elapsed)
37Power steering fluid
pressure switchEngine: Idling after
warming upWhen steering
wheel is stationarySystem voltage
When steering
wheel is turned0±3V
38Control relay
(Power supply)
Ignition switch: OFFSystem voltage
(Power su ly)
Ignition switch: ON0±3V
45A/C switchEngine: Idle speedTurn the A/C
switch OFF0±3V
Turn the A/C
switch ON (A/C
compressor is
operating)System voltage
51Ignition switch ± STEngine: Cranking8V or more
52Intake air temperature
sensorIgnition switch:
ONWhen intake air
temperature is
0
C3.2 ± 3.8V
When intake air
temperature is
20
C2.3 ± 2.9V
When intake air
temperature is
40
C1.5 ± 2.1V
When intake air
temperature is
80
C0.4 ± 1.0V
56Oxygen sensorEngine: Running at 2,500 r/min after
warmed up (Check using a digital type
voltmeter)0
0.8V
(Changes repeatedly)
60Backup power supplyIgnition switch: OFFSystem voltage
61Sensor impressed
voltageIgnition switch: ON4.5 ± 5.5V
62Ignition switch ± IGIgnition switch: ONSystem voltage

MPI ± TroubleshootingMPI ± Troubleshooting13A-66
Terminal No.Normal condition Check condition (Engine condition) Check item
63Engine coolant
temperature sensorIgnition switch:
ONWhen engine
coolant tempera-
ture is 0C3.2 ± 3.8V
When engine
coolant tempera-
ture is 20C2.3 ± 2.9V
When engine
coolant tempera-
ture is 40C1.3 ± 1.9V
When engine
coolant tempera-
ture is 80C0.3 ± 0.9V
64Throttle position
sensorIgnition switch:
ONSet throttle valve
to idle position0.3 ± 1.0V
Fully open throttle
valve4.5 ± 5.5V
65Barometric pressure
sensorIgnition switch:
ONWhen altitude is
0m3.7 ± 4.3V
When altitude is
1,200m3.2 ± 3.8V
66Vehicle speed sensor
Ignition switch: ON

Move the vehicle slowly forward0
5V
(Changes repeatedly)
67Idle position switchIgnition switch:
ONSet throttle valve
to idle position0±1V
Slightly open
throttle valve4V or more
68Top dead centre sensorEngine: Cranking0.4 ± 3.0V
Engine: Idle speed0.5 ± 2.0V
69Crank angle sensorEngine: Cranking0.4 ± 4.0V
Engine: Idle speed1.5 ± 2.5V
70Air flow sensorEngine: Idle speed2.2 ± 3.2V
Engine r/min: 2,500r/min
71Inhibitor switch Ignition switch:
ONSet selector lever
to P or N0±3V
Set selector lever
to Other than P or
N8 ± 14V

MPI ± Troubleshooting13A-68
Terminal No. Normal condition (Check condition)Inspection item
4±12Stepper motor coil (A1)28 ± 33 W (At 20
C)
17 ± 12Stepper motor coil (A2)
5±12Stepper motor coil (B1)
18 ± 12Stepper motor coil (B2)
6±12EGR control solenoid valve36 ± 44 W (At 20
C)
9±12Purge control solenoid valve36 ± 44 W (At 20
C)
13 ± Body earthEngine-ECU earthContinuity (0W)
26 ±Body earthEngine-ECU earth
35 ± 12Oxygen sensor heaterApprox. 12 W (At 20
C)
52 ± 72Intake air temperature sensor5.3 ± 6.7 kW (When intake air temperature is 0
C)
2.3 ± 3.0 kW (When intake air temperature is 20
C)
1.0 ± 1.5 kW (When intake air temperature is 40
C)
0.30 ± 0.42 kW (When intake air temperature is 80
C)
63 ± 72Engine coolant temperature sensor5.1 ± 6.5 kW (When coolant temperature is 0
C)
2.1 ± 2.7 kW (When coolant temperature is 20
C)
0.9 ± 1.3 kW (When coolant temperature is 40
C)
0.26 ± 0.36 kW (When coolant temperature is 80
C)
67 ± 72Idle position switchContinuity (when throttle valve is at idle position)
No continuity (when throttle valve is slightly open)
71 ±Body earthInhibitor switch Continuity (when select lever is at P or N)
No continuity (when select lever is at D, 2, L or R)