1998 MITSUBISHI LANCER EVOLUTION IV air condition

MPI – Troubleshooting13-26
7. INSPECTION PROCEDURE USING
OSCILLOSCOPE
7-1 AIR FLOW SENSOR (AFS)
Observing waveforms displayed on the oscilloscope allows
you to visually identify possible unusual disturbances in
waveform that could temporarily occur in the air flow sensor
output.

(1) Disconnect the air flow sensor connector and connect
the special tool (Test Harness: MB991709) to it. (Ensure
that all terminals are connected.)
(2) Connect the oscilloscope probe to terminal no. 3 of air
flow sensor connector.
NOTE
If the engine ECU connector is used, connect the
oscilloscope probe to terminal no. 90.
(3) Perform the same steps from here on as with the 4G9
engine.
7-2 CAMSHAFT POSITION SENSOR AND CRANK
ANGLE SENSOR
Perform the same steps as with the conventional 4G9 engine
for the inspection.
7-3 INJECTOR
Observing waveforms displayed on the oscilloscope allows
you to visually check the conditions of injector drive signals
actually output from the engine ECU.
Injector Control Signal (Oscilloscope 1)

(1) Disconnect the injector connector and connect the special
tool (Test Harness: MB991348) to the circuit. (Ensure
that the terminals on both the power supply and engine
ECU sides are connected.)
(2) Connect the oscilloscope probe to terminal no. 2 of injector
connector.
NOTE
If the engine ECU connector is used for the measurement,
take measurements at each of the following terminals.
Connect the oscilloscope probe to terminal no. 1 when
the waveform is observed with no. 1 cylinder, to terminal
no. 14 when the waveform is observed with no. 2 cylinder,
to terminal no. 2 when the waveform is observed with
no. 3 cylinder, and to terminal no. 15 when the waveform
is observed with no. 4 cylinder.
Oscilloscope
Oscilloscope

MPI – On-vehicle Service13-32
6. INTAKE AIR TEMPERATURE SENSOR
CHECK
1. Disconnect the air flow sensor connector.
2. Measure resistance between terminals 5 and 6.
Standard value:
2.3 – 3.0 kΩ (at 20C)
0.30 – 0.42 kΩ (at 80C)
3. Measure resistance while heating the sensor using a hair
drier.
Normal condition:
Temperature (C)Resistance (kΩ)
HigherSmaller
4. If the value deviates from the standard value or the
resistance remains unchanged, replace the air flow sensor
assembly.
7. ENGINE COOLANT TEMPERATURE
SENSOR CHECK
The engine coolant temperature sensor is located as shown
on the left.
Standard value:
2.1 – 2.7 kΩ (at 20C)
0.26 – 0.36 kΩ (at 80C)
8. OXYGEN SENSOR CHECK

The sensor connector is located as shown on the left.

(1) Disconnect the oxygen sensor connector and connect
the special tool (Test Harness: MD998464) to the oxygen
sensor connector.
Equipment sideconnector
Air flow sensor
Intake air temperature sensor
Engine coolant
temperature sensor
Oxygen sensor equipment side connector
Oxygen sensor connector
Oxygen sensor

INTAKE AND EXHAUST – On-vehicle Service15-4
3. WASTEGATE ACTUATOR CHECK
(1) Connect a hand pump (pressure type) to the nipple.
(2) Gradually increase the pressure being applied to check
for the pressure at which the wastegate actuator rod starts
moving (approx. 1 mm stroke).
Standard value: Approx. 100 kPa {1.02 kg/cm
2}
Caution
Do not apply a pressure more than 120 kPa {1.23
kg/cm
2} to prevent the diaphragm from being
damaged.
(3) If the pressure drastically deviates from the standard
value, check the actuator or wastegate valve and, if
necessary, replace the actuator or turbocharger assembly.
4. WASTEGATE SOLENOID VALVE CHECK
4-1 OPERATION CHECK
(1) Connect a hand vacuum pump to nipple A of the solenoid
valve.
(2) Using jumper wires, connect the solenoid valve terminal
to battery terminals.
(3) Disconnecting and reconnecting the jumper wire on the
(–) terminal side, apply vacuum to check for airtightness.
Jumper wireNipple B conditionNormally
ConnectedOpenVacuum leaks.
PluggedVacuum retained.
DisconnectedOpenVacuum retained.
4-2 COIL RESISTANCE CHECK
Measure the resistance across solenoid valve terminals.
Standard value: 62 – 74 Ω (at 20
C)
5. AIR BYPASS VALVE CHECK
(1) Remove the air bypass valve.
(2) Connect a hand vacuum pump to the air bypass valve
nipple.
(3) Apply a vacuum of approx. 45 kPa {340 mmHg} and
check that the valve is airtight.
(4) Increase the vacuum and check for valve operation.
VacuumValve operation
Approx. 53 kPa {400 mmHg}Starts moving

INTAKE AND EXHAUST – On-vehicle Service15-5
6. SECONDARY AIR CONTROL SYSTEM
CHECK
(1) Start the engine and let it run at idle speed.
(2) Short-circuit the no. 6 terminal of the engine ECU
connector using a jumper wire and check at this time
that the secondary air valve lifts.
At this time, the engine ECU connector should be
connected.
7. SECONDARY AIR CONTROL SOLENOID
VALVE CHECK
7-1 OPERATION CHECK
(1) Disconnect the vacuum hose (white stripe, yellow stripe)
from the solenoid valve.
(2) Disconnect the harness connector.
(3) Connect a hand vacuum pump to nipple A of the solenoid
valve.
(4) Using jumper wires, connect the solenoid valve terminal
to battery terminals.
(5) Disconnecting and reconnecting the jumper wire on the
(–) terminal side, apply vacuum to check for airtightness.
Jumper wireNipple B conditionNormally
ConnectedOpenVacuum leaks.
PluggedVacuum retained.
DisconnectedOpenVacuum leaks.
7-2 COIL RESISTANCE CHECK
Measure the resistance across solenoid valve terminals.
Standard value: 28 – 36 Ω (at 20
C)
Secondary air control
solenoid valve
Battery

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

REAR AXLE – Troubleshooting 27-14
Code No. 52: Longitudinal acceleration sensor systemProbable cause
This code is output when the longitudinal acceleration exceeds a predetermined value
while the vehicle is running with both ABS and brakes being inactive.
Defective longitudinal acceleration sensor

Defective harness or connector

Defective AYC-ECU
NG
Check and repair the harness between
longitudinal acceleration sensor and
AYC-ECU.
OK
Check the trouble symptom.
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connector:
B-95NG
Repair
OK
Measure at B-95 AYC-ECU connector.

Connector connected

Ignition switch: ON

Voltage across 3 and body ground
OK:2.4 V to 2.6 V (where vehicle
in horizontal position)NGCheck the following connectors:
B-95, B-52, D-20
Check the acceleration sensor.
(Refer to P.27-52.)NG
Replace
NG
Repair
Code No. 61: Stop lamp switch systemProbable cause
This code is output under either of the following conditions:

Stop lamp switch remains ON for 15 min. or more.

There is an open-circuit in the harness between AYC-ECU and stop lamp switch.
Defective stop lamp switch

Defective harness or connector

Defective AYC-ECU
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connector:
B-95NG
Repair
OK
Measure at the B-95 AYC-ECU con-
nector.

Disconnect the connector and
measure at the harness side.

Voltage across 11 and body ground

Brake pedal not depressed.
OK:1 V or lessNGCheck and repair the harness between
AYC-ECU and stop lamp switch.
Check the stop lamp switch.NG
Replace

REAR AXLE – Troubleshooting 27-22
INSPECTION PROCEDURE 2
AYC warning lamp remains lit up after the engine has
started.
Probable cause
The AYC warning lamp ON circuit is probably short-circuited.
Defective combination meter

Defective harness (short-circuit)

Defective AYC-ECU
NOTE
This symptom is limited only when AYC-ECU power supply is in normal condition and the diagnosis
code is correct.
OK
Replace combination meter.
NO
Check the harness between AYC
warning lamp and AYC-ECU.NG
Repair
Does the AYC warning lamp goes out
when the B-96 AYC-ECU connector
is disconnected?YESReplace AYC-ECU.
INSPECTION PROCEDURE 3
AYC is inoperative.
Unable to start or accelerate on slippery road surfaces.
Probable cause
The hydraulic oil level is probably low, there is an oil leak, the hydraulic unit is defective,
or the torque transfer differential is defective.
Low hydraulic oil level

Oil leak

Defective hydraulic unit

Defective torque transfer differential
NOTE
This symptom is limited only when the diagnosis code is correct.
NG
Replace the hydraulic unit.
NG
Replace the torque transfer differential.
Check the trouble symptom.
NG
Replace AYC fluid.
OK
Correct
Check the trouble symptom.NO
Replace the torque transfer differential.
OK
Is foreign matter trapped in the hydrau-
lic line?YES
Repair
OK
Check the AYC for operation.OKCheck the AYC fluid.
NG
Add hydraulic oil.
NG
Check hydraulic pressure.NGBleed the system of air.
Check the hydraulic oil level.NGCheck for oil leak.OK
Repair

ABS – TroubleshootingABS – Troubleshooting35B-6
Code No. 27: AYC monitor system (defective AYC)Probable cause
This code is output when the AYC monitor signal becomes faulty.
Defective AYC-ECU

Defective ABS-ECU

Defective harness or connector
OK
Replace the ABS-ECU.
OK
MUT-II data list
AYC signal
OKOFF to be displayed when the
engine runs at idle with the
vehicle stationary.NGReplace AYC-ECU.
OK
Check the harness between ABS-ECU
and AYC-ECU.NG
Repair
Check the following connectors:
B-25, B-96NG
Repair
Code No. 32: Acceleration sensor (longitudinal accelera-
tion) circuit systemProbable cause
This code is output under either of the following conditions:

The output from the acceleration sensor (longitudinal acceleration) becomes 0.5
V or less, or 4.5 V or more.

The acceleration sensor (longitudinal acceleration) harness is open- or
short-circuited.
Defective acceleration sensor (longitudinal accelera-
tion)

Defective harness or connector

Defective ABS-ECU
OK
Check the trouble symptom.NGReplace ABS-ECU.
OK
Check the trouble symptom.NGCheck and repair the harness between
acceleration sensor (longitudinal
acceleration) and ABS-ECU.
OK
Check the trouble symptom.NGCheck and repair the harness between
general-purpose fuse No. 6 and
acceleration sensor (longitudinal
acceleration).
OK
Replace ABS-ECU.
OK
Check the following connector:
B-24NG
Repair
OK
Measure at B-24 ABS-ECU connector.

Connect the connector.

Ignition switch: ON

Voltage across 4 and 17
OK:2.4 – 2.6 V
(horizontal position)NGCheck the following connectors:
B-24, D-20, B-52NG
Repair
NG
Check the harness between accelera-
tion sensor (longitudinal acceleration)
and ABS-ECU.NG
Repair
OK
Check the trouble symptom.
OK
Check the valve relay.NG
Replace
(1) NGCheck the following connectors:
D-20, B-49, B-75NG
Repair
Check the following connector:
D-20, B-49, B-75NG
Repair
(2) NG
Measure at D-20 acceleration sensor
(longitudinal acceleration) connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON
(1) Voltage across 1 and body ground
OK:Battery voltage
(2) Continuity across 3 and body
ground
OK:Conducting