1999 MITSUBISHI LANCER EVOLUTION VI engine

MPI – Troubleshooting13-13
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 or short-circuited
harness wire of the vehicle speed sensor circuit

Malfunction of the engine-ECU
OK
Check the ignition switch. (Refer to GROUP 54 – Ignition Switch.)
2. NG
OK
Replace the engine-ECU.
3. NG
OK
Replace the engine-ECU.
NG
Check the harness wire
between the engine-ECU
and the vehicle speed
sensor connector.NG
Repair
OK
Check trouble symptom.
OK
Check the following
connectors:
A-19, B-62NG
Repair
NG
Check the harness wire
between the engine-ECU
and the vehicle speed
sensor connector.NG
Repair
OK
Check trouble symptom.
Check the following
connector: B-62NG
Repair
NG
Check the harness wire
between the vehicle
speed sensor and ignition
switch connector.NG
Repair
OK
Check trouble symptom.
OK
Measure at the vehicle speed sensor connector A-19.

Disconnect the connector, and measure at the harness
side.
1. Voltage between 1 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 3 and earth (Ignition switch: ON)
OK:4.8 – 5.2 V
3. Continuity between 2 and earth
OK:Continuity1. NGCheck the following
connectors:
B-64, B-74, B-76NG
Repair
Check the vehicle speed sensor. (Refer to GROUP 54 – Combina-
tion Meters.)NG
Replace
Check the harness wire between the vehicle speed sensor and
the earth, and repair if necessary.

MPI – Troubleshooting13-14
Code No. 25 Barometric pressure 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

Sensor output voltage is 4.5 V or more (corresponding to a barometric pressure
of 114 kPa or more) for 4 seconds.
or

Sensor output voltage is 0.2 V or less (corresponding to a barometric pressure
of 5.33 kPa or less) for 4 seconds.
Malfunction of the barometric pressure sensor

Improper connector contact, open or short-circuited
harness wire of the barometric pressure sensor circuit

Malfunction of the engine-ECU
Measure at the air flow sensor con-
nector A-25.

Connect the connector. (Use
the test harness: MB991709)

Voltage between 2 and earth
(Ignition switch: ON)
OK:3.7–4.3 V (Altitude: 0 m)
3.2–3.8V (Altitude:
1,200 m)NGMeasure at the air flow sensor con-
nector A-25.

Disconnect the connector, and
measure at the harness side.

Voltage between 1 and earth
(Ignition switch: ON)
OK:4.8–5.2 V

Continuity between 5 and earth
OK:ContinuityNGCheck the following connector:
B-62NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between
the engine-ECU and the baromet-
ric pressure sensor connector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following connector:
A-25NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between
the engine-ECU and the baromet-
ric pressure sensor connector.NG
Repair
OK
Replace the air flow sensor.
OK
Measure at the engine-ECU con-
nector B-62.

Connect the connector.

Voltage between 85 and earth
(Ignition switch: ON)
OK:3.7–4.3 V (Altitude: 0 m)
3.2–3.8V (Altitude:
1,200 m)NGCheck the harness wire between
the engine-ECU and the baromet-
ric pressure sensor connector, and
repair if necessary.
Check the following connector:
A-25, B-62
OK
Check trouble symptom.
NG
Replace the engine-ECU.NG
Repair OK

MPI – Troubleshooting13-15
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 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.

Actuator test by MUT-II is not carried out.
Set conditions

Surge voltage of injector coil is not detected for 4 seconds.
Malfunction of the injector

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

Malfunction of the engine-ECU
OK
Check trouble symptom.NGCheck the harness wire between the
resistor and the injector connector, and
repair if necessary.
Check the injector control circuit.
(Refer to P.13-55, INSPECTION PRO-
CEDURE 50.)OK
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
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 connector,
and repair if necessary.
Check the injector. (Refer to P.13-34.)*
Check the resistor. (Refer to P.13-34.)*NG
Replace
NOTE
*: Refer to Workshop Manual for LANCER EVOLUTION-IV and EVOLUTION-V (Pub. No. S9806CNCP9).

MPI – Troubleshooting13-16
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 cranking.
Set conditions

Abnormal rotation due to misfire is detected by crank angle sensor (Either one
of coils fails).
Malfunction of the ignition coil

Improper connector contact, open or short-circuited
harness wire of the ignition primary circuit

Malfunction of the engine-ECU
OK
OK
Check trouble symptom.
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 the 2 and earth
OK: Continuity1. NGCheck the following connectors:
B-65, B-76OKCheck trouble symptom.
NG
Check the harness wire between the
ignition coil and ignition switch connec-
tor, and repair if necessary.
2. NGCheck the following connector: B-59NG
Repair
NG
Check the harness wire between the
engine-ECU and ignition coil connector.OKReplace the engine-ECU.
NG
Repair
3. NG
Check the harness wire between the
ignition coil connector and earth, and
repair if necessary.
Check the following connectors:
A-110, A-111NG
Repair
Check trouble symptom.
NG
Check the following items.

Check the spark plugs, spark plug
cables.

Check the compression pressure.
NG
Repair
Check the ignition coil. (Refer to
GROUP 16 – IGNITION SYSTEM.)NG
Replace
OK
OK

MPI – Troubleshooting13-17
Code No. 64 Alternator FR terminal systemProbable cause
Range of Check

Engine speed is approx. 50 r/min or more
Set Conditions

The input voltage from the alternator FR terminal is higher than 4.5 V for 20 seconds.
Open circuit in alternator FR terminal circuit

Malfunction of the engine-ECU
Measure at the alternator connector A-05.

Connect the connector. (Use the test harness: MB991519.)

Voltage between 4 (blue clip) and earth
(Engine: Idling)
(Radiator fan: Stopped)
(Headlamp: OFF → ON)
(Brake lamp: OFF → ON)
(Rear window defogger switch: OFF → ON)
OK:Voltage drops 0.2 to 3.5 VOKReplace the engine-ECU.
NG
Measure at the alternator connector 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
connectors: B-60, A-88NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between the engine-ECU
and the alternator con-
nector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following connector: A-05NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between the engine-ECU and the alternator
connector.NG
Repair
OK
Replace the alternator.

MPI – Troubleshooting13-18
INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble symptomInspection
procedure
No.Reference page
Communication
with MUT-IIis
Communication with all systems is impossible.113-20
with MUT-II is
impossible.
Communication with engine-ECU only is impossible.213-20
Engine warning
lamp and
related parts
The engine warning lamp does not illuminate right after the
ignition switch is turned to the ON position.313-21
related partsThe engine warning lamp remains illuminating and never goes
out.413-21
StartingNo initial combustion (starting impossible)513-22
Initial combustion but no complete combustion
(starting impossible)613-23
Long time to start (improper starting)713-24
Idling stability
(Improper idling)
Unstable idling (Rough idling, hunting)813-25
(Improper idling)
Idling speed is high. (Improper idling speed)913-26
Idling speed is low. (Improper idling speed)1013-27
Idling stability
(Engine stalls)
When the engine is cold, it stalls at idling. (Die out)1113-28
(Engine stalls)
When the engine is hot, it stalls at idling. (Die out)1213-29
The engine stalls when starting the car. (Pass out)1313-30
The engine stalls when decelerating.1413-30
DrivingHesitation, sag or stumble1513-31
The feeling of impact or vibration when accelerating1613-31
The feeling of impact or vibration when decelerating1713-32
Poor acceleration1813-32
Surge1913-33
Knocking2013-33
Dieseling2113-33
Too high CO and HC concentration when idling2213-34
Low alternator output voltage (approx. 12.3 V)2313-35

MPI – Troubleshooting
Vehicle
speedInitial accel-
erator pedal
depression
NormalHesitation
Sag
Time
(Figure 1)(Figure 2)
Normal
Initial accel-
erator pedal
depression
IdlingStumble
TimeVehicle
speed
13-19
PROBLEM SYMPTOMS TABLE (FOR YOUR INFORMATION)
ItemsSymptom
StartingWon’t startThe starter is used to crank the engine, but there is no combustion within the
cylinders, and the engine won’t start.
Fires up and diesThere is combustion within the cylinders, but then the engine soon stalls.
Hard startingEngine starts after cranking a while.
Idling
stability
HuntingEngine speed doesn’t remain constant; changes at idle.
stability
Rough idleUsually, a judgement can be based upon the movement of the tachometer
pointer, and the vibration transmitted to the steering wheel, shift lever, body, etc.
This is called rough idle.
Incorrect idle speedThe engine doesn’t idle at the usual correct speed.
Engine stall
(Die out)The engine stalls when the foot is taken from the accelerator pedal, regardless
of whether the vehicles is moving or not.
Engine stall
(Pass out)The engine stalls when the accelerator pedal is depressed or while it is being
used.
DrivingHesitation, Sag“Hesitation” is the delay in response of the vehicle speed (engine speed) that
occurs when the accelerator is depressed in order to accelerate from the speed
at which the vehicle is now traveling, or a temporary drop in vehicle speed
(engine speed) during such acceleration. Serious hesitation is called “sag”.
(Refer to Figure 1.)
Poor accelerationPoor acceleration is inability to obtain an acceleration corresponding to the
degree of throttle opening, even though acceleration is smooth, or the inability
to reach maximum speed.
StumbleEngine speed increase is delayed when the accelerator pedal is initially
depressed for acceleration. (Refer to Figure 2.)
ShockThe feeling of a comparatively large impact or vibration when the engine is
accelerated or decelerated.
SurgeThis is repeated surging ahead during constant speed travel or during variable
speed travel.
KnockingA sharp sound like a hammer striking the cylinder walls during driving and which
adversely affects driving.
StoppingRun on
(“Dieseling”)The condition in which the engine continues to run after the ignition switch is
turned to OFF. Also called “Dieseling”.

MPI – Troubleshooting13-20
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
INSPECTION PROCEDURE 1
Communication with MUT-II is impossible.
(Communication with all systems is impossible.)
Probable cause
The cause is probably a defect in the power supply system (including earth) for the
diagnosis line.
Malfunction of the diagnosis connector

Malfunction of the harness wire
Measure at the diagnostic connector
B-22.

Voltage between 16 and earth
OK:System voltageNGCheck the following connectors:
B-49, B-75, B-73
B-73, B-80NG
Repair
OK
Check trouble symptom.NGCheck the harness wire between the
power supply and diagnostic connector,
and repair if necessary.OK
Measure at the diagnostic connector
B-22.

Continuity between 4 and earth

Continuity between 5 and earth
OK:ContinuityNGCheck the earth wire, and repair if nec-
essary.
OK
Replace the MUT-II.
INSPECTION PROCEDURE 2
MUT-II communication with engine-ECU is impossible.
Probable cause
One of the following causes may be suspected.

No power supply to engine-ECU.

Defective earth circuit of engine-ECU.

Defective engine-ECU.

Improper communication line between engine-ECU and MUT-II
Malfunction of engine-ECU power supply circuit

Malfunction of engine-ECU

Open circuit between immobilizer-ECU and diagnosis
connector
OK
Check the engine-ECU power supply and earth circuit.
(Refer to P.13-53, INSPECTION PROCEDURE 45.)
NG
Check the harness wire between engine-ECU and diagnosis con-
nector.NG
Repair
OK
Check trouble symptom.
Check the following connectors:
B-22, B-65, B-32, B-61NG
Repair