ESP MITSUBISHI LANCER EVOLUTION IV 1998 User Guide

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

MPI – On-vehicle Service13-33
(2) Check that there is continuity (11 to 18 Ω at 20C) across
terminal no. 1 (special tool red clip) and terminal no. 3
(special tool blue clip) of the oxygen sensor connector.
(3) If there is no continuity, replace the oxygen sensor.
(4) Run the engine until the engine coolant temperature
exceeds 80C.
(5) Using jumper wires, connect oxygen sensor terminal no.
1 (special tool red clip) and terminal no. 3 (special tool
blue clip) to battery (+) and (–) terminal, respectively.
Caution
Make sure of the correct connections: if a wrong
connection is made, a broken oxygen sensor results.
(6) Connect a digital voltmeter between terminal no. 2 (special
tool black clip) and terminal no. 4 (special tool white clip).
(7) Race the engine repeatedly to measure the oxygen sensor
output voltage.
Standard value:
EngineOxygen sensor
output voltageNOTE
When
engine is
raced0.6 – 1.0 VWhen engine racing is
repeated to enrich air-fuel
ratio, an operational oxygen
sensor should output a volt-
age of 0.6 to 1.0 V.
NOTE
Use the same procedures to remove and install the oxygen
sensor.
Red clip
Blue clip
MD998464
Red clip
Blue clip
MD998464 Black clip
White clip

MPI – On-vehicle Service13-35
11. FUEL PUMP RELAY NO.2 CHECK
(1) Remove fuel pump relay No.2.
(2) Using jumper wires, connect fuel pump relay No.2 terminal
(3) to battery (+) terminal, and terminal (1) to battery
(–) terminal, respectively.
(3) Connecting and disconnecting the jumper wire on the
battery (–) terminal end, check for continuity across
terminal (2) and terminal (5), and across terminal (4) and
terminal (5), of fuel pump relay No.2.
Jumper wireContinuity across
terminals (2) and (5)Continuity across
terminals (4) and (5)
ConnectedNoYe s
DisconnectedYe sNo
(4) If the continuity is checked abnormally, replace fuel pump
relay No.2.
12. FUEL PUMP RESISTOR CHECK
(1) Disconnect the fuel pump resistor connector.
(2) Measure resistance across the terminals.
Standard value: 0.6 – 0.9 Ω
(3) If the measurement falls outside the specified range,
replace the fuel pump resistor.
Fuel pump relay No.2
Fuel pump resistor

ENGINE ELECTRICAL – Charging System16-3
REMOVAL SERVICE POINTS

APOWER STEERING, A/C COMPRESSOR, AND
ALTERNATOR DRIVE BELT REMOVAL
(1) Align the hole in the auto tensioner bracket with that
in the arm and insert a screwdriver into the holes.
(2) Remove the drive belt.

BDELIVERY PIPE, INJECTOR, AND PRESSURE
REGULATOR ASSEMBLY REMOVAL
After the mounting points have been loosened, slightly move
the corresponding part to allow for a space for removal of
the alternator.

CALTERNATOR REMOVAL
Push the engine all the way up with a garage jack and remove
the alternator upward the engine compartment.
Phillips
screwdriver
Hole in arm
Auto tensioner
Hole in bracket

22A-1
MANUAL
TRANSMISSION
CONTENTS
LUBRICANTS 2. . . . . . . . . . . . . . . . . . . . . . . . . . .
SPECIAL TOOLS 2. . . . . . . . . . . . . . . . . . . . . . . .
ON-VEHICLE SERVICE 3. . . . . . . . . . . . . . . . . .
1. Transmission Oil Check 3. . . . . . . . . . . . . . . .
2. Transmission Oil Replacement 3. . . . . . . . . .
3. Transfer Oil Check 3. . . . . . . . . . . . . . . . . . . .
4. Transfer Oil Replacement 3. . . . . . . . . . . . . .
TRANSMISSION CONTROL* 4. . . . . . . . . . . . .
Shift Lever Assembly 6. . . . . . . . . . . . . . . . . . . . . .
TRANSMISSION ASSEMBLY 7. . . . . . . . . . . . .
TRANSFER ASSEMBLY 10. . . . . . . . . . . . . . . .
WARNING REGARDING SERVICING OF SUPPLEMENTAL RESTRAINT SYSTEM (SRS) EQUIPPED VEHICLES
(1) Thoroughly review this manual, especially GROUP 52B – Supplemental Restraint System (SRS) before beginning any
service or maintenance of any component of the SRS or any SRS-related component.
(2) When removing or installing the components indicated in the table of contents by an asterisk (*), use special care not
to apply shocks to SRS-related components.

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 27-19
Code No. 82: Electric pump systemProbable cause
This code is output if the pressure switch is not set to high-pressure position despite
the AYC-ECU’s command to drive the AYC relay for a given period of time.
Low hydraulic oil level

Oil leak

Defective fusible link

Defective AYC relay

Defective harness or connector

Defective AYC motor

Defective accumulator pressure switch

Defective AYC-ECU
OK
Replace AYC-ECU.
Check the harness
between AYC relay and
AYC motor, and between
AYC motor and body
ground.NG
Replace
NG
OK
Check the trouble symptom.
OK
Check the following
connectors:
A-126, B-94, B-27, F-32NG
Repair
OK
Replace AYC-ECU.
NG
Check the harness
between AYC-ECU and
accumulator pressure
switch.NG
Repair
NG
Check and repair the har-
ness between fusible link
no. 10 and AYC relay.
OK
Check the trouble symp-
tom.
OK
Replace the hydraulic unit
for a defective accumula-
tor pressure switch.
NO
Repair the leak.
OK
Check the trouble symptom.
NG
Check the following
connector: A-126NG
Repair
YES
Add hydraulic oil.
Is the hydraulic oil level correct in the reservoir tank?
(Refer to P.27-29.)NOIs there a hydraulic oil leak?
Measure at A-126 AYC relay connector.

Disconnect the connector and measure at the harness side.

Voltage across 5 and body ground
OK: Battery voltage
NG
NO
Can pump be operated?YESMeasure at F-31 accumulator pressure switch connector.

Disconnect the connector and measure at the harness side.

Ignition switch: ON

Voltage across 2 and body ground
OK:Battery voltage
YES
Is diagnosis code no. 81 output?YESCheck the AYC relay system. (Refer to P.27-18.)
NG
Check the following
connectors: B-95, B-94,
D-06, F-30, F-31NG
Repair
OK

Check AYC relay for
continuity.
(Refer to P.27-52.)

Check AYC motor for
operation.NG
Repair

REAR AXLE – Troubleshooting 27-20
Code No. 83: Electric pump systemProbable cause
This code is output if the pressure switch is not set to low-pressure position despite
the AYC-ECU’s command to change the driving force.
Defective accumulator pressure switch

Defective harness or connector
OK
Replace AYC-ECU.
NG
Check the harness between AYC-ECU
and accumulator pressure switch.NG
Repair
OK
Check the trouble symptom.
NG
Check and repair the harness between
accumulator pressure switch and body
ground.
OK
Check the trouble symptom.
(2) NG
Check the following connectors:
F-31, F-30NG
Repair
NO
Measure at F-31 accumulator pressure
switch connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON
(1) Voltage across 2 and body ground
OK:Battery voltage
(2) Continuity across 1 and body
ground
OK:ConductingOKReplace the hydraulic unit for a defec-
tive accumulator pressure switch.
OK
Check and repair the harness between
AYC relay and AYC motor.
NO
Is diagnosis code no. 71, 72, or 73
output?YES
Check the proportioning valve
system (code no. 71).
(Refer to P.27-15.)

Check the directional control valve
(right) system (code no. 72).
(Refer to P.27-16.)

Check the directional control valve
(left) system (code no. 73).
(Refer to P.27-17.)
(1) NGCheck the following connectors:
B-95, B-94, D-06, F-30, F-31NG
Repair
Does the AYC motor continue turning
when the ignition switch is turned ON?YESCheck the AYC relay for continuity.
(Refer to P.27-52.)NG
Repair

REAR AXLE – LSD Case Assembly 27-48
BSCREW TIGHTENING
(1) Align the alignment mark on differential case A with that
on differential case B.
(2) Tighten the screws connecting differential case A and
B a uniform amount little by little in the diagonal order.
NOTE
If tightening the screws does not bring the two cases
properly together, spring plates are not probably
assembled properly. Reassemble from the start.
CLSD DIFFERENTIAL TORQUE CHECK
(1) Using the special tool, check for differential torque.
Standard value:
When new clutch plate is
installed Nm {kgf
m}When existing clutch plate is
reused Nm {kgf
m}
5 – 19 {0.5 – 1.9}2 – 19 {0.2 – 1.9}
NOTE
Before measuring the differential torque, first turn the
gears so they snug each other, then take measurements
during rotation.
(2) If the measurement falls outside the specified range,
disassemble the differential case assembly and repair
or replace defective parts.
INSPECTION
1. DIFFERENTIAL CASE INTERNAL PARTS
CONTACT/SLIDING SURFACE CHECK
(1) Clean the disassembled parts with cleaning oil and dry
them with compressed air.
(2) Check each plate, disc, and pressure ring for the following:
A. Friction and sliding surfaces of friction discs, friction
plates, and spring plates.
Replace a defective part with heat discoloration and
excessive wear with a new one, as it degrades locking
performance.
NOTE
If the inner periphery of the friction face shows traces
of harsh contact, it is because of the spring tension
of each plate, disc and other part. Do not confuse
this with abnormal wear.
B. Inner periphery and outer periphery protrusions of
friction discs, friction plates, and spring plates.
Replace a cracked or damaged part with a new one.
C. Friction and sliding surfaces between pressure rings
and friction discs.
MB990989MB990990
Friction disc
Friction plateSpring plate
Pressure ring