1998 MITSUBISHI LANCER EVOLUTION IV air condition

MPI – Troubleshooting13-14
Code No.31 Detonation 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.
Engine speed is approx. 5,000 r/min or more
Set conditions
The change in the detonation sensor output voltage (detonation sensor peak voltage
at each 1/2 revolution of the crankshaft) is less than 0.06 V for 200 times in succession.Malfunction of the detonation sensor
Improper connector contact, open circuit or
short-circuited harness wire of the detonation sensor
circuit
Malfunction of the engine-ECU
Measure at the detonation sensor con-
nector A-96.
Disconnect the connector and
measure at the harness side.
Continuity between 2 and earth
OK:ContinuityOKCheck the following connector:
B-62NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between the
engine-ECU and the detonation sensor
connector.OKReplace the detonation sensor.
Check trouble symptom.
NG
Replace the engine-ECU.
NG
Repair
NG
Check the harness wire between the
detonation sensor and earth, and repair
if necessary.
Code No. 41 Injector systemProbable cause
Range of Check
Engine speed is approx. 50–1,000 r/min
The throttle position sensor output voltage is 1.15 V or less.
Set conditions
Surge voltage of injector coil is not detected for 4 seconds.Malfunction of the injector
Improper connector contact, open circuit or
short-circuited harness wire of the injector circuit
Malfunction of the engine-ECU
NG
Check the harness wire between the
resistor and the injector connector, and
repair if necessary.
OK
Check trouble symptom.
OK
Check the injector control circuit.
OK
Measure at the injector connectors
A-53, A-54, A-55, A-56.
Disconnect the connector, and
measure at the harness side.
Voltage between 1 and earth
(Ignition switch: ON)
OK:System voltageNGCheck the following connector:
A-125NG
Repair
Check the injector. (Refer to P.13-34.)
Check the resistor. (Refer to P.13-34.)NG
Replace
OK
Measure at the resistor connector
A-125.
Disconnect the connector, and
measure at the harness side.
Voltage between 3 and earth
(Ignition switch: ON)
OK:System voltageNGCheck the harness wire between the
control relay and the resistor connec-
tor, and repair if necessary.

MPI – Troubleshooting13-15
Code No. 44 Ignition coil and power transistor unit systemProbable cause
Range of Check
Engine speed is approx. 50 – 4,000 r/min.
Engine is not being cranked.
Set conditions
Abnormal engine speed is detected due to misfiring by crank angle sensor. (One
of two coils fails.)Malfunction of the ignition coil
Improper connector contact, open circuit or
short-circuited harness wire of the ignition primary
circuit
Malfunction of the engine-ECU.
NG
Check the harness wire between the ignition coil and ignition switch
connector, and repair if necessary.
2. NG
OK
Replace the engine-ECU.
3. NG
NG
Check the following items.
Check the spark plugs and spark plug cables.
Check the compression pressure.
OK
Check trouble symptom.
OK
Check the following
connectors:
A-110, A-111NG
Repair
NG
Check the harness wire
between the engine-ECU
and ignition coil connec-
tor.NG
Repair
OK
Check trouble symptom.
Check the following
connector:
B-59NG
Repair
OK
Check trouble symptom.
OK
Measure at the ignition coil connectors A-110, A-111.
Disconnect the connector, and measure at the harness.
1. Voltage between 1 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 3 and earth (Engine: Cranking)
OK:0.5 – 4.0 V
3. Continuity between 2 and earth
OK:Continuity1. NGCheck the following
connectors:
B-65, B-76NG
Repair
Check the ignition coil. (Refer to Group 16 – Ignition System.)NG
Replace
Check the harness wire between the ignition coil connector and
earth, and repair if necessary.

MPI – Troubleshooting13-16
Code No. 64 Alternator FR Terminal SystemProbable cause
Range of Check
Engine speed is approximately 50 r/min or more.
Set conditions
Input voltage at the alternator FR terminal is 4.5 V or more for 20 seconds.Open circuit in alternator FR terminal circuit
Malfunction of the engine-ECU.
OK
Replace the alternator.
NG
Check the harness wire between
the engine-ECU and alternator
connector.NG
Repair
OK
Check trouble symptom.
Measure at the alternator connec-
tor
Connect the connector.
(Use test harness MB991519.)
Voltage between 4 (blue clip)
and earth
(Engine: Idling)
(Radiator fan: Stopped)
(Headlamp: OFF → ON)
(Brake lamp: OFF → ON)
(Rear defogger switch: OFF
→ ON)
OK:Voltage drops by 0.2 to
3.5 V.NGMeasure at the alternator connec-
tor A-05.
Disconnect the connector, and
measure at the harness side.
Voltage between 4 and earth
(Ignition switch: ON)
OK:4.8 – 5.2 VNGCheck the following connec-
tors:
B-60, A-88NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between
the engine-ECU and alternator
connector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following connector:
A-05NG
Repair
OK
Replace the engine-ECU.

MPI – Troubleshooting13-18
5. SERVICE DATA LIST

Item
No.Inspection
itemInspection contentsNormal condition
11Oxygen
sensorEngine: After having been warmed
up
Air/fuel mixture is made leaner when
When at 4,000 r/min, engine is
suddenly decelerated200 mV or less
Air/fuel mixture is made leaner when
decelerating, and is made richer
when racing.
When engine is suddenly
raced600 – 1,000 mV
Engine: After having been warmed
up
The ox
ygen sensor signal is used to
Engine is idling400 mV or less
(Chan
ges)The oxygen sensor signal is used to
check the air/fuel mixture ratio, and
control condition is also checked by
the ECU.2,500 r/min
(Changes)
600 – 1,000 mV
12Air flow
sensor*
Engine coolant temperature:
8095C
Engine is idling17 – 43 Hz
sensor*80 – 95C
Lamps, electric cooling fan and
all accessories: OFF
2,500 r/min46 – 86 Hz
all accessories: OFF
Transmission: NeutralEngine is racedFrequency increases
in response to racing
13Intake air
temperature
sensor
Ignition switch: ON or with engine
runningWhen intake air temperature
is –20C–20C
sensorWhen intake air temperature
is 0C0C
When intake air temperature
is 20C20C
When intake air temperature
is 40C40C
When intake air temperature
is 80C80C
14Throttle
position
Ignition switch: ONSet to idle position300 – 1,000 mV
position
sensor
Gradually openIncreases in proportion
to throttle opening
angle
Open fully4,500 – 5,500 mV
16Power
supply
voltageIgnition switch: ONSystem voltage
18Cranking
signal Ignition switch: ONEngine: StoppedOFF
g
(ignition
switch-ST)Engine: CrankingON
NOTE
*: When the car is new (distance it travelled is less than 500 km), output frequency of the air flow sensor may
become about 10% higher.

MPI – Troubleshooting13-21

Descriptions other than those given below are the same as for the EVOLUTION-IV.
Item
No.Inspection
itemInspection contentsNormal condition
12Air flow
sensor*1Engine coolant temperature:
80–95C
Engine is idling12 – 38 Hz
sensor*180 – 95C
Lamps, electric cooling fan and
all accessories: OFF
2,500 r/min36 – 76 Hz
all accessories: OFF
Transmission: NeutralEngine is racedFrequency increases
in response to racing
41Injector
drive time*2Engine: Cranking*2When engine coolant temper-
ature is 0C27 – 40 ms
When engine coolant temper-
ature is 20C14.5 – 21.7 ms
When engine coolant temper-
ature is 80C3.8 – 5.6 ms
Injector
drive time*3Engine coolant temperature:
8095C
Engine is idling0.9 – 2.1 ms
drive time *380 – 95C
Lamps, electric cooling fan and
all accessories: OFF
2,500 r/min0.7 – 1.9 ms
all accessories: OFF
Transmission: NeutralWhen engine is suddenly
racedIncreases
44Ignition
advance
Engine: After having been
warmed up
Engine is idling0 – 13BTDC
advancewarmed up
Timing lamp is set.2,500 r/min24 – 44BTDC
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 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.
*3: In a new vehicle (driven approximately 500 km or less), the injector drive time is sometimes 10 % longer than
the standard time.

MPI – Troubleshooting13-22
6. ENGINE-ECU INSPECTION
6-1 TERMINAL VOLTAGES
Engine ECU connector
Terminal
No.Check itemCheck condition (Engine condition)Normal condition
1No.1 injectorWhile engine is idling after having been warmed up,
suddenly depress the accelerator pedal
Momentarily drops
slightlyfrom 1114V
14No.2 injector
suddenly depress the accelerator pedal.slightly from 11 – 14 V.
2No.3 injector
15No.4 injector
3Fuel pressure control
valve
Ignition switch: ONBattery voltage
valve
Engine: Cranking to idling (within about two minutes)0 – 3 V to battery
voltage
4Stepper motor coil (A1)Engine: Immediately after engine has been started
f
or warming up
Changes repeatedly
f
rom battery voltage to
17Stepper motor coil (A2)
for warming upfrom battery voltage to
0 – 6 V and from 0 – 6
V to battery voltage5Stepper motor coil (B1)V to battery voltage.
18Stepper motor coil (B2)
6Secondary air control
solenoid valveIgnition switch: ONBattery voltage
8Fuel pump relayIgnition switch: ONBattery voltage
Engine: Idling0 – 3 V
10Power transistor unit
(A)Engine speed: 3,000 r/min0.3 – 3.0 V
23Power transistor unit
(B)
11Wastegate solenoid
valve
Ignition switch: ONBattery voltage
valve
Engine: At idle after having been warmed up (when
premium gasoline is used)0 – 3 V
12Power supplyIgnition switch: ONBattery voltage
25
19Air flow sensor reset
signal
Engine: Idling0 – 1 V
signal
Engine speed: 3,000 r/min6 – 9 V
20Fan motor relay (HI)Fan not operating (coolant temperature: 90C or
below)Battery voltage
Fan at high speed (coolant temperature: 105C or
above)0 – 3 V

MPI – Troubleshooting13-24
Terminal
No.Normal condition Check condition (Engine condition) Check item
72Intake air temperature
sensorIgnition switch: ONWhen intake air tempera-
ture is 0C3.2 – 3.8 V
When intake air tempera-
ture is 20C2.3 – 2.9 V
When intake air tempera-
ture is 40C1.5 – 2.1 V
When intake air tempera-
ture is 80C0.4 – 1.0 V
76Oxygen sensorEngine: Running at 2,000 r/min after having been
warmed up (Check using a digital type voltmeter)0 ↔ 0.8 V
(Changes repeatedly)
80Backup power supplyIgnition switch: OFFBattery voltage
81Sensor impressed
voltageIgnition switch: ON4.5 – 5.5 V
82Ignition switch-IGIgnition switch: ONBattery voltage
83Engine coolant
temperature sensorIgnition switch: ONWhen engine coolant
temperature is 0C3.2 – 3.8 V
When engine coolant
temperature is 20C2.3 – 2.9 V
When engine coolant
temperature is 40C1.3 – 1.9 V
When engine coolant
temperature is 80C0.3 – 0.9 V
84Throttle position sensorIgnition switch: ONSet throttle valve to idle
position0.3 – 1.0 V
Fully open throttle valve4.5 – 5.5 V
85Barometric pressure
sensor
Ignition switch: ONWhen altitude is 0 m3.7 – 4.3 V
sensor
When altitude is 1,200 m3.2 – 3.8 V
86Vehicle speed sensorIgnition switch: ON
Move the vehicle slowly forward0 ↔ 5 V
(Changes repeatedly)
87Idle position switchIgnition switch: ONSet throttle valve to idle
position0 – 1 V
Slightly open throttle
valve4 V or more
88Camshaft position
sensor
Engine: Cranking0.4 – 3.0 V
sensor
Engine: Idle speed0.5 – 2.0 V
89Crank angle sensorEngine: Cranking0.4 – 4.0 V
Engine: Idle speed1.5 – 2.5 V
90Air flow sensorEngine: Idle speed2.2 – 3.2 V
Engine speed: 2,500 r/min

MPI – Troubleshooting13-25
6-2 RESISTANCE AND CONTINUITY BETWEEN HARNESS SIDE CONNECTORS AND
TERMINALS
Engine-ECU Harness Side Connector Terminal Arrangement
Terminal No.Inspection itemNormal condition (Check condition)
1 – 12No.1 injector2 – 3 Ω (At 20C)
14 – 12No.2 injector
2 – 12No.3 injector
15 – 12No.4 injector
3 – 12Fuel pressure control valve28 – 36 Ω (At 20C)
4 – 12Stepper motor coil (A1)28 – 33 Ω (At 20C)
17 – 12Stepper motor coil (A2)
5 – 12Stepper motor coil (B1)
18 – 12Stepper motor coil (B2)
6 – 12Secondary air control solenoid valve28 – 36 Ω (At 20C)
11 – 12Wastegate solenoid valve62 – 74 Ω (At 20C)
13 – Body earthEngine-ECU earthContinuity established (0 Ω)
26 – Body earth
60 – 12Oxygen sensor heater (EVOLUTION-V
only)11 – 18 Ω (at 20C)
72 – 92Intake air temperature sensor5.3 – 6.7 kΩ (When intake air temperature is 0C)
2.3 – 3.0 kΩ (When intake air temperature is 20C)
1.0 – 1.5 kΩ (When intake air temperature is 40C)
0.30 – 0.42 kΩ (When intake air temperature is 80C)
74 – 77High temperature sensor3 Ω or less
83 – 92Engine coolant temperature sensor5.1 – 6.5 kΩ (When coolant temperature is 0C)
2.1 – 2.7 kΩ (When coolant temperature is 20C)
0.9 – 1.3 kΩ (When coolant temperature is 40C)
0.26 – 0.36 kΩ (When coolant temperature is 80C)
87 – 92Idle position switchContinuity established (when throttle valve is at idle
position)
No continuity (when throttle valve is slightly open)
91 – Body earth–Continuity established