1998 MITSUBISHI LANCER EVOLUTION IV turn signal

MPI – Troubleshooting13-6
TROUBLESHOOTING
1. DIAGNOSIS FUNCTION
1-1 ENGINE WARNING LAMP (CHECK ENGINE LAMP)
If an abnormality occurs in any of the following items related
to the Multipoint Fuel Injection (MPI) system, the engine
warning lamp will illuminate.
If the lamp remains illuminated or if the lamp illuminates while
the engine is running, check the diagnosis code output.
Engine warning lamp inspection items
Engine-ECU
Air flow sensor (AFS)
Intake air temperature sensor
Throttle position sensor (TPS)
Engine coolant temperature sensor
Crank angle sensor
Camshaft position sensor
Barometric pressure sensor
Detonation sensor
Injector
Ignition coil, power transister
Misfire
1-2 METHOD OF READING AND ERASING DIAGNOSIS
CODES
(1) Use the special tool to earth No.1 terminal (diagnosis
control terminal) of the diagnosis connector.
(2) To check ABS system, remove the valve relay.
NOTE
That is because the valve relay is off and the warning
lamp remains illuminated if there is a fault in the ABS
system.
(3) Turn off the ignition switch.
(4) Read out a diagnosis code by observing how the warning
lamp flashes.
Indication of diagnosis code by warning lamp
When the diagnosis code No.24 is outputWhen no diagnosis code is output*
On
Off
1.5 secs.0.5 sec.
0.5 sec.
Pause
time 3
secs.Tens signalPlace
division
2 secs.Units signal
A03X0113
On
Off
0.5 sec.
0.25 sec.
NOTE
*: Even if the ABS system is normal, removing the valve relay causes the diagnosis code No.52 to
be output.
Engine warning lamp
(check engine lamp)

MPI – Troubleshooting13-7
1-3 ERASING DIAGNOSIS CODES
(1) Turn the ignition switch to OFF.
(2) After disconnecting the battery cable from the battery (–) terminal for 10 seconds or more, reconnect
the cable.
(3) After the engine has warmed up, run it at idle for about 15 minutes.
1-4 FAIL-SAFE FUNCTION REFERENCE TABLE
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 sensor (AFS)(1) 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 25C.
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 80C.
(This condition is maintained until the ignition switch is turned off even when the sensor signal
returns normal.)
Camshaft position
sensor(1) Injects fuel to all cylinders simultaneously for 4 seconds.
(However, after the ignition switch is turned to ON, the No. 1 cylinder top dead centre
is not detected at all.)
(2) Lets the fan motor (radiator and condensor) run at high speed.
Barometric pressure
sensorControls as if the barometric pressure is 101 kPa {760 mmHg}.
Detonation sensorSwitches the ignition timing from ignition timing for super petrol to ignition timing for standard
petrol.
Ignition coil, power
transistorCuts off the fuel supply to cylinders with an abnormal ignition.
Alternator FR terminalDoes not control the output of the alternator according to an electrical load. (works as a
normal alternator)
Misfire
(Evolution-V only)Cuts off the fuel to the misfiring cylinder if a misfire that could damage the catalyst is detected.

MPI – Troubleshooting13-9
Code No. 13 Intake air temperature 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 4.6 V or more (corresponding to an intake air temperature
of –45C or less) for 4 seconds.
or
Sensor output voltage is 0.2V or less (corresponding to an intake air temperature
of 125C or more) for 4 seconds.Malfunction of the intake air temperature sensor
Improper connector contact, open circuit or
short-circuited harness wire of the intake air
temperature sensor circuit
Malfunction of the engine-ECU
OK
Check trouble symptom.
Check the intake air temperature sen-
sor. (Refer to P.13-32.)NGReplace air flow sensor.
OK
Measure at the air flow sensor connec-
tor A-25.
Disconnect the connector, and
measure at the harness side.
Voltage between 6 and earth
(Ignition switch: ON)
OK:4.5–4.9 V
Continuity between 5 and earth
OK:ContinuityNGCheck the following connector:
C-62NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between the
engine-ECU and the intake air temper-
ature sensor connector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following connector:
A-25NG
Repair
NG
Code No. 14 Throttle position sensor (TPS) 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
The sensor output voltage is 0.2 V or less for 4 seconds.Malfunction of the throttle position sensor
Improper connector contact, open circuit or
short-circuited harness wire of the throttle position
sensor circuit
Improper “ON” state of idle position switch
Short circuit of the idle position switch signal line
Malfunction of the engine-ECU
Check the throttle position sensor.NG
Replace
OK
Measure at the throttle position sensor
connector A-16.
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 4 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 throttle position
sensor connector.NG
Repair
OK
Replace the engine-ECU. OK
Check the throttle position sensor out-
put circuit.

MPI – Troubleshooting13-12
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
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 – Troubleshooting13-27

Observation conditions
Probe selector switch× 10
AC-GND-DCDC
VOLTS/DIV.1 V
TIME/DIV.0.5 ms
Misc.–
Engine speedIdle

The power supply voltage is being normally applied and, when a signal is received from the engine
ECU, the voltage drops to around 0 V for the period of time equivalent to its drive signal.
When the signal from the engine ECU turns OFF, the counter emf of the coil causes a voltage peak
to develop, thus resuming the power supply voltage.
Injector drive time:
The fuel injection time as determined by the engine ECU according to the output values of sensors
including AFS. Injector drive time = effective injection time + invalid injection time (Invalid injection
time: corrects operation time lag caused by a power supply voltage drop)
Solenoid coil counter emf:
When the signal from the engine ECU turns OFF, counter emf occurs in the injector coil (approx.
65 to 75 V).
Power supply voltage:
The power supply voltage is being applied in the absence of a signal from the engine ECU. If this
voltage is low, it extends the invalid injection time and, thus, the drive time.

Point A: Strength of solenoid coil counter emf
Solenoid coil counter emf is low or zero.Injector solenoid shorting
Point B: Injector drive time
When the engine is suddenly raced, the drive time temporarily
extends by a wide margin and soon returns to the normal
drive time corresponding to the engine speed.
Point A
Point B
Injector
drive timeSolenoid counter emf
(approx. 7 × 10 V)
Power supply voltage
At idle
During racing

REAR AXLE – Troubleshooting 27-10
Code No. 26: Wheel speed sensor system (faulty output
signal)Probable cause
This code is output if the speed of one of the four wheels exceeds a specified level
when the vehicle speed is 20 km/h or more. At this time, the warning lamp is turned
on.
Defective harness or connector

Defective AYC-ECU

Defective ABS-ECU

OK
Replace ABS-ECU.
NG
Check harness between AYC-ECU
and ABS-ECU.NG
Repair
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
NG
Check the following connectors:
B-24, B-95NG
Repair
OK
Check the trouble symptom.
NO
Measure at B-95 AYC-ECU connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Turn tire at 1/2 to 1 revolution/sec.

Voltage across 6/7/8/9 and body
ground.
OK:42 mV or more (when mea-
sured with a circuit tester)
120 mV-P or more (when
measured with an oscillo-
scope)NGCheck the following connector:
B-95
Is ABS diagnosis code No. 15 output?YESTroubleshooting
NG
Repair

NG
Check and repair the harness between
speed sensor and AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connectors:
B-95, B-52, B-17, A-26, A-50, D-04,
D-14, D-19NG
Repair
OK
Check wheel bearing.NG
Replace
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connector:
B-95NG
Repair
OK
Check speed sensor output voltage.
(Refer to P.27-31.)NGCheck speed sensor and rotor.
Check speed sensor for installation.NG
Repair
NG
Replace

REAR AXLE – Troubleshooting 27-12
Code No. 33: Steer sensor (ST-N) systemProbable cause
This code is output when the steering wheel is turned 400 or more in the same
direction with ST-N OFF (HIGH voltage).
Defective steer sensor

Defective harness or connector

Defective AYC-ECU
NG
Replace AYC-ECU.
Check the trouble symptom.
OK
Replace the steer sensor.
NG
Check the harness between steer sen-
sor and AYC-ECU.NG
Repair
OK
Replace AYC-ECU.
OK
Check the trouble symptom.
Measure at B-95 AYC-ECU connector.

Connector connected.

Ignition switch: ON

Turn steering wheel about 90 in
either direction from the straight-
ahead position.

Voltage across 17 and body
ground.
OK:The voltage increases from
about 0.5 V or less to about
3.5 V.NGCheck the following connectors:
B-95, B-65, B-98NG
Repair
Code No. 34: Steer sensor (ST-1, ST-2) systemProbable cause
This code is output if a turning condition is detected for a cumulative period of time
of 15 min. or more, during which there is no change in the steer sensor (ST-1, ST-2)
signals with the wheel speed 15 km/h or more.
Defective steer sensor

Defective harness or connector

Defective AYC-ECU
NG
Replace AYC-ECU.
Check the trouble symptom.
OK
Replace the steer sensor.
NG
Check the harness between steer sen-
sor and AYC-ECU.NG
Repair
OK
Replace AYC-ECU.
OK
Check the trouble symptom.
Measure at B-95 AYC-ECU connector.

Connector connected.

Ignition switch: ON

Voltage across 4/5 and body
ground
OK:The voltage alternates
between about 0.5 V and
about 3 V as the steering
wheel is turned.NGCheck the following connectors:
B-95, B-65, B-98NG
Repair

ABS – Troubleshooting35B-9
Code No. 53: Motor relay systemProbable cause
This code is output under any of the following conditions:

No signals are input to the motor monitor when the motor relay is ON (motor
does not run, etc.).

A signal is being input to the motor monitor for 3 sec. or more when the motor
relay is OFF (motor continues running, etc.).

The motor relay is inoperative.
Defective motor relay

Defective harness or connector

Defective hydraulic unit

Defective ABS-ECU
Caution
(1) If the motor relay contacts fuse, the motor continues running even when the ignition switch
is turned OFF. In this case, immediately remove fusible link No. 8 (60 A) or disconnect the
A-22 connector or A-77 motor relay connector of the hydraulic unit. Overloading the motor
results in a rundown battery.
(2) Driving the motor through actuator test runs down the battery. After the test, run the engine
for some while.
OK
Check the trouble symptom.NGCheck and repair the harness between
fusible link No. 8 and motor relay.
OK
Check the trouble symptom.NGCheck and repair the harness between
motor relay and hydraulic unit.
OK
Check the trouble symptom.NGCheck and repair the harness between
motor relay and ABS-ECU motor
monitor terminal No. 49.
OK
Check the motor for operation.NGReplace ABS-ECU.
OK
Check the following connectors:
A-22, A-77, B-25NG
Repair
OK
Check the motor for operation.NGReplace the hydraulic unit.
OK
Measure at A-77 motor relay connector
and B-25 ABS-ECU connector.

Disconnect the connector and
measure at the harness side.

Continuity across the following
terminals
Motor relay ABS-ECU
side side
4–49
OK:ConductingNGCheck the following connectors:
A-77, B-25NG
Repair
OK
Measure at A-77 motor relay connector
and A-22 hydraulic unit connector.

Disconnect the connector and
measure at the harness side.

Continuity across the following
terminals
Motor relay Hydraulic
side unit side
4–12
OK:ConductingNGCheck the following connectors:
A-22, A-77NG
Repair
OK
Measure at A-77 motor relay connec-
tor.

Disconnect the connector and
measure at the harness side.

Voltage across 5 and body ground
OK:Battery voltageNGCheck the following connector:
A-77NG
Repair
Check the motor relay.NGReplace the motor relay.