1998 MITSUBISHI LANCER EVOLUTION IV ignition

16-1
ENGINE
ELECTRICAL
CONTENTS
CHARGING SYSTEM 2. . . . . . . . . . . . . . . .
ALTERNATOR 2. . . . . . . . . . . . . . . . . . . . . . . . . . .
IGNITION SYSTEM 4. . . . . . . . . . . . . . . . . .
ON-VEHICLE SERVICE 4. . . . . . . . . . . . . . . . . . .
1. Ignition Coil with Built-in Power Transistor
Check 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Spark Plug Check, Cleaning, and
Replacement 4. . . . . . . . . . . . . . . . . . . . . . . . . .
CAMSHAFT POSITION SENSOR AND
CRANK ANGLE SENSOR
5 . . . . . . . . . . . . .

ENGINE ELECTRICAL – Ignition System16-4
IGNITION SYSTEM
ON-VEHICLE SERVICE
1. IGNITION COIL WITH BUILT-IN POWER TRANSISTOR CHECK
Secondary coil resistance measurement
Standard value: 15 – 21 kΩ
2. SPARK PLUG CHECK, CLEANING, AND REPLACEMENT
Check the plug gap and replace if the limit is exceeded.
Caution
(1) Do not attempt to adjust the gap of the platinum plug.
(2) Cleaning the platinum plug can damage platinum tips. If a cleaning is needed, use a plug
cleaner and finish cleaning within 20 seconds to protect the electrodes. Never use wire brushes.
Standard values and limits:
ManufacturerModelStandard value (mm)Limit (mm)
NGKPGR7A0.7 – 0.80.95
DENSOP22PR80.7 – 0.80.95

ENGINE ELECTRICAL – Ignition System16-5
CAMSHAFT POSITION SENSOR AND CRANK ANGLE SENSOR
REMOVAL AND INSTALLATION
Pre-removal and Post-installation Operation
Timing Belt Removal and Installation
(Refer to GROUP 11.)
Unit: Nm {kgf
m}
49 {5.0}
5
9 {0.9}9 {0.9}
9 {0.9} 39 {4.0} 3 {0.3}
2
3
41
Removal steps
1. Camshaft position sensor
2. Center cover

A3. Power steering oil pump4. Power steering oil pump bracket
5. Crank angle sensor
REMOVAL SERVICE POINT

APOWER STEERING OIL PUMP REMOVAL
Remove the power steering oil pump with hose from the power
steering oil pump bracket.
NOTE
String up the oil pump which has been removed onto a location
that does not hamper removal and installation of the power
steering oil pump bracket.

REAR AXLE – Troubleshooting 27-7
4. INSPECTION PROCEDURES FOR DIAGNOSIS CODES
Code No. 12: Power supply voltage (valve power supply)
systemProbable cause
This code is output when the AYC-ECU power supply voltage drops below, goes
beyond, a specified level.
Defective harness or connector

Defective battery

Defective AYC-ECU
NOTE
Refer to the corresponding item if any other diagnosis code is being output.
Is the battery voltage correct?NG
Replace
OK
Measure at B-96 AYC-ECU connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Voltage across 31 and body ground
OK:Battery voltageNGCheck the following connectors:
B-96, B-94, B-49, B-75, B-76
OK
Check the trouble symptom.
NG
Check and repair harness between
ignition switch (IG
2) and AYC-ECU. OKReplace AYC-ECU.NG
Repair
Code No. 21, 22, 23, 24: Wheel speed sensor systemProbable cause
This code is output if any one of three wheel speed sensors fails to provide an input
even after the other wheel exceeded 8 km/h.
Defective harness or connector

Defective ABS-ECU

Defective AYC-ECU

OK
Replace AYC-ECU.
OK
Replace ABS-ECU.
NG
Check harness between AYC-ECU
and ABS-ECU.NG
Repair
OK
Check the trouble symptom.
Is an ABS diagnosis code No. 21, 22,
23, or 24 output?YESTroubleshooting
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)OKCheck the following connector:
B-95
OK
Check the trouble symptom.
NG
Check the following connectors:
B-24, B-95NG
RepairNG
Repair

REAR AXLE – Troubleshooting 27-9
Code No. 25: Wrong-diameter tireProbable cause
This code is output if the speed of any one of the four wheels exceeds a specified
level with respect to the average of the four wheel speed sensor outputs when the
steering wheel is in the straight-ahead position and the vehicle speed exceeds 20
km/h. At this time, the warning lamp does not light up.
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: OK

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)OKCheck the following connector:
B-95
YES
Is ABS diagnosis code No. 15 output?YESTroubleshooting
Are correct tires mounted on all four
wheels?NO
Repair
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.
YES
Check speed sensor for installation.NG
Repair
Are correct tires mounted on all four
wheels?NO
Repair
NG
Replace

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 27-11
Code No. 31: Steer sensor (ST-1, ST-2, ST-N) systemProbable cause
This code is output when any of the steer sensors ST-1, ST-2, and ST-N is open-circuited
or the steer sensor ground wire is open-circuited.
Defective steer sensor

Defective harness or connector

Defective AYC-ECU
OK
Replace the steer sensor.
NG
Check the harness between steer sen-
sor and AYC-ECU.NG
Repair
NG
Check and repair the harness between
speed sensor and AYC-ECU.
OK
Check the trouble symptom.
OK
Check the trouble symptom.
OK
Check the following connectors:
B-95, B-65, B-98NG
Repair
NG: Voltage remains
at 4 V or more.
Measure at B-98 steer sensor connec-
tor.

Disconnect the connector and
measure at the harness side.

Continuity across 3 and body
ground
OK:ConductingNGCheck the following connectors:
B-98, B-50NG
Repair
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
Measure at B-95 AYC-ECU connector.

Connector connected.

Ignition switch: ON

Voltage across 4/5/17 and body ground.
OK:The voltage alternates between about
3 V and about 0.5 V when the steering
wheel is turned.OKCheck the following connector:
B-95NG
Repair
NG: Voltage alternates
between 4 V or
more and 0.5 V.NG: Voltage
remains
at 0 V.
Code No. 32: Steer sensor (ST-N) systemProbable cause
This code is output when the steering wheel is considered to be turned 40 or more
as determined with ST-1 and ST-2 with ST-N ON (LOW voltage).
Defective steer sensor

Defective harness or connector

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

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

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

Voltage across 17 and body
ground.
OK:No continuityNGCheck the following connectors:
B-95, B-65, B-98NG
Repair
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.OKCheck the following connector:
B-95NG
Repair

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