low oil pressure MITSUBISHI LANCER EVOLUTION IV 1998 User Guide

MPI – On-vehicle Service13-31
5. MPI SYSTEM COMPONENTS LAYOUT
NameSymbolNameSymbol
A/C switchQExhaust temperature warning lampS
A/C relayHFuel pressure control valveA
Air flow sensor (with a built-in intake air temperaturesensor and barometric pressure sensor)FIgnition coil and power transistor unitLsensor and barometric pressure sensor)InjectorB
Camshaft position sensorMISC servoD
Control relay and fuel pump relayPOxygen sensorK
Coolant temperature sensorEPower steering fluid pressure switchI
Crank angle sensorJSecondary air control solenoid valveN
Detonation sensorCThrottle position sensor (with a built-in idle switch)D
Diagnosis connectorR
Engine ECUOVehicle speed sensorT
Engine warning lampSWastegate solenoid valveG

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 27-22
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

REAR AXLE – On-vehicle Service 27-29
3-2 TORQUE TRANSFER MECHANISM
(1) Remove the drain plug to discharge the gear oil.
(2) Fit the drain plug and tighten it to the specified torque.
(3) Remove the filler plug and add the specified gear oil
up to the bottom end of the filler plug hole.
Specified gear oil:
MITSUBISHI GENUINE DIA QUEEN SUPER AYC
FLUID
Quantity used: 0.70
0
0.05dm3{0.700
0.05}
(4) Fit the filler plug and tighten it to the specified torque.
4. FLUID LEVEL CHECK
(1) Remove the maintenance lid located in the luggage
compartment.
(2) If the vehicle has been run, leave it for 5 min. or more
in an ordinary temperature (10
C to 30
C) to allow the
accumulator internal pressure to drop.
NOTE
If the ambient temperature is less than 10
C or less,
allow more time to leave the vehicle to stand idle.
(3) Check that the fluid level in the oil reservoir is in the
range between MAX and MIN.
(4) If the fluid level is lower than MIN, add the specified
fluid.
Specified fluid: MITSUBISHI DIA QUEEN ATF-SPII
(5) Reinstall the maintenance lid.
5. BLEEDING
(1) Lift up the vehicle.
(2) Remove the cap of the left bleeder screw on the torque
transfer differential and connect a vinyl hose.
(3) Gradually turn the steering wheel clockwise from the
straight-ahead position. At this time, loosen the left bleeder
screw and check that fluid is discharged with air.
(4) After air has been completely discharged, tighten the
bleeder screw.
Caution
While the system is being bled of air, add fluid as
necessary to ensure that it is left in the oil reservoir
during the entire procedure.
(5) Repeat steps (3) and (4) two to three times until no air
bubbles are recognized in the fluid that comes out. Then,
tighten the bleeder screw to the specified torque.
Tightening torque: 9 Nm {0.9 kgf
m}
(6) Perform steps (2) through (5) for the right bleeder screw.
Note, however, that the steering wheel should be turned
counterclockwise.
Filler plug
49 Nm {5.0 kgf
m}
Gear oil
Drain plug
49 Nm
{5.0 kgf
m}
Bleeder
screws Vinyl hose

REAR AXLE – LSD Case Assembly 27-47
ASSEMBLY SERVICE POINTS
AINSTALLATION TO DIFFERENTIAL CASE B
Before starting the assembly procedure, perform the following
steps to adjust dimensional differences (clutch plate friction
force) in the axial direction of the components inside the
differential case and axial clearance of the differential side
gear.
(1) Place friction discs (two each) and friction plates (three
each) one on top of another as illustrated and, using
a micrometer, measure the thickness of each of the right
and left assemblies. Select different discs and plates so
that the difference between the right and left assemblies
falls within the specified range.
Standard value: 0 – 0.05 mm
NOTE
If a new part is used, note that the friction disc comes
in two thicknesses: 1.6 mm and 1.7 mm.
(2) Measure the thickness of each of the right and left spring
plates.
(3) Assemble the pressure ring internal parts (pinion shaft
and pressure ring), friction plates, and friction discs and,
using a micrometer, measure the overall width.
NOTE
When taking measurements, press the assembly from
both sides so that the pinion shaft makes a positive contact
with the groove in the pressure ring.
(4) Find value (A) which is the thickness measured in step
(3) added to the thickness of two spring plates.
(5) Find dimension (B) between the spring plate faying
surfaces when differential case A and B are assembled
together.
B = C + D – E
(6) If the clearance between the spring plate and differential
case (B – A) is outside the specified range, change the
friction discs and make adjustments.
Standard value: 0.06 – 0.25 mm
(7) Coat each part with the specified gear oil and mount
it in the specified direction and order into differential case
B.
Gear oil: DIA QUEEN LSD GEAR OIL
NOTE
Apply a careful coat of gear oil to the contacting and
sliding surfaces.
Groove
Differential
case ADifferential case B
Spring plate
Friction disc
Friction plate

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

REAR AXLE – LSD Case Assembly 27-49
Grind a dented or scratched part with oil stone and
then lap and correct with a compound on a surface
plate.
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.
(3) Check the following parts for contact and sliding surfaces
(D to M) and correct burrs and dents with oil stone.
D: Sliding surfaces of side gear and case
E: Contacting surfaces of differential case and spring
plate
F: Contacting surfaces of pressure ring and differential
case inner face
G: Sliding surfaces of pressure ring hole and side gear
H: Protrusions on outer periphery of pressure ring
I: Pressure ring inner surface and differential pinion
gear spherical surface
J: Pressure ring V-groove and pinion shaft V
K: Sliding surfaces of pinion shaft and differential pinion
gear hole
L: Side gear grooves on outer periphery
M: Slits in inner periphery of differential
2. FRICTION PLATE AND FRICTION DISC
DISTORTION CHECK
Apply a dial indicator to the friction plate or disc on a surface
plate and, turning the friction plate or disc, measure the
distortion (flatness).
Limit: 0.08 mm (total runout)
3. FRICTION PLATE, FRICTION DISC, AND SPRING
PLATE WEAR CHECK
(1) For the purpose of determining wear, measure thickness
(A, B) of the friction surface and protrusion at several
places and find the difference between the two.
Limit: 0.1 mm
(2) If the wear exceeds the limit, replace the part with a
new one.