1999 MITSUBISHI LANCER EVOLUTION VI voltage

REAR AXLE – Troubleshooting 27-12
Code No. 41: TPS systemProbable cause
This code is output when the input from the throttle position sensor falls short of
0.2 V.
Defective TPS

Defective harness or connector

Defective AYC-ECU
OK
Replace AYC-ECU.
NG
Check and repair the harness between
AYC-ECU and TPS.
OK
Check the trouble symptom.
NO
Measure at B-95 AYC-ECU connector.

Connector connected.

Ignition switch: ON

Voltage across 18 and body ground

Fully open the throttle valve.
OK:4.5 – 5.0 VNGCheck the following connector:
B-95
Is the MPI diagnosis code No. 14 out-
put?YESRefer to GROUP 13A TROUBLE-
SHOOTING.
NG
Repair
Code No. 51: Longitudinal acceleration sensor systemProbable cause
Code No. 56: Lateral acceleration sensor system
This code is output when the output from the acceleration sensor becomes 0.5 V
or less or 4.5 V or more.
Defective longitudinal acceleration sensor

Defective lateral acceleration sensor

Defective harness or connector

Defective AYC-ECU
NG
Replace the acceleration sensor.
OK
Check the trouble symptom.
OK
Check and repair the harness between
acceleration sensor and ignition
switch.
OK
Check the trouble symptom.
NG
Check and repair the harness between
acceleration sensor and AYC-ECU.
NGReplace AYC-ECU.
OK
Check the following connectors:
D-20, D-32
OK
Check the trouble symptom.
OK
Check the trouble symptom.
NG: 4.5 V or more
Check the acceleration sensor. (Refer
to P.27-42.)NG
Replace
NG: 0.5 V or less
Check at D-20, D-32 acceleration sen-
sor connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Voltage across 1 and body ground
OK:System voltageNGCheck the following connectors:
D-20, D-32, B-49, B-75, B-76NG
Check and repair the harness between
acceleration sensor and AYC-ECU.
NG
Measure at D-20, D-32 acceleration
sensor connector.

Connector connected.

Ignition switch: ON

Voltage across 2 and body ground
OK:0.5 – 4.5 VOKCheck the following connectors:
D-20, D-32NG
Repair
Measure at B-95 AYC-ECU connector.

Connector connected.

Ignition switch: ON

Voltage across 1/3 and body
ground
OK:0.5 – 4.5 VOKCheck the following connector:
B-95NG
Repair
NG
Replace

REAR AXLE – Troubleshooting 27-13
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.27-42.)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 27-18
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.27-33.)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: System voltage
NG
NO
MUT-II Actuator test:
No. 12 Electric pump operation check
OK: Pump operation sounds are heardOKMeasure 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:System voltage
YES
Is diagnosis code no. 81 output?YESCheck the AYC relay system. (Refer to P.27-17.)
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.27-42.)

Check AYC motor for
operation.NG
Repair

REAR AXLE – Troubleshooting 27-19
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:System 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.27-14.)

Check the directional control valve
(right) system (code no. 72).
(Refer to P.27-15.)

Check the directional control valve
(left) system (code no. 73).
(Refer to P.27-16.)
(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.27-42.)NG
Repair

REAR AXLE – Troubleshooting 27-20
5. INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble symptomInspection
procedure No.Ref. page
Communication between MUT-II and the whole system is not possible.127-20
Communicatio between MUT-II and AYC-ECU is not possible.227-21
AYC warning lamp does not light up when the ignition key is turned to “ON” (engine
stationary).327-22
AYC warning lamp remains lit up after the engine has started.427-23
AYC is inoperative.
Unable to start or accelerate on slippery road surfaces.527-23
Rear tires are noisy during low-speed cornering.
Vehicle skews.627-24
6. INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
INSPECTION PROCEDURE 1
Communication between MUT-II and the whole system is
not possible.
Probable cause
The cause may be a malfunction of the power supply circuit or the ground circuit
of the diagnosis connector.
Defective diagnosis connector

Defective harness or connector
NG
Check and repair the harness between
power supply and diagnosis connector.
OK
Check the trouble symptom.
NG
Check and repair the harness between
body ground and diagnosis connector.
OK
Check the trouble symptom.
OK
Replace MUT-II.
Check the following connectors:
B-22, B-50NG
Repair
OK
Measure at B-22 diagnosis connector.

Disconnect the connector and
measure at the harness side.

Continuity across 4/5 and body
ground
OK:ConductingNG
Measure at B-22 diagnosis combina-
tion meter connector.

Voltage across 16 and body ground
OK:System voltageNGCheck the following connectors:
B-22, B-49, B-75, B-73NG
Repair

REAR AXLE – Troubleshooting 27-21
INSPECTION PROCEDURE 2
Communication between MUT-II and the AYC-ECU is not
possible.
Probable cause
The cause may be a malfunction of the AYC-ECU power supply circuit or an open
circuit in the diagnosis output circuit.
Blown fuse

Defective harness or connector

Defective AYC-ECU
NG
Check and repair the harness between
AYC-ECU and diagnosis connctor.
OK
Check the trouble symptom.
OK
Check the following symptom.
NG
Check and repair the harness between
ignition switch (IG
2) and AYC-ECU.
OK
Check the trouble symptom.
OK
Replace AYC-ECU.
Check the following connectors:
B-96, B-94, B-49, B-75, B-76NG
Repair
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:System voltageNG
Measure at B-22 diagnosis connector
and B-95 AYC-ECU connector.

Disconnect the connectors and
measure at the harness side.

Continuity across 1 of B-22 and
10 of B-95

Continuity across 7 of B-22 and
23 of B-95
OK:ConductingNGCheck the following connectors:
B-95, B-65, B-22NG
Repair
OK
Measure at B-95 and B-96 AYC-ECU
connectors.

Disconnect the connectors and
measure at the harness side.

Continuity across 26/46 and body
ground
OK:ConductingNGCheck the following connectors:
B-95, B-96NG
Replace
Check and repair the harness between
AYC-ECU and earth.
NG

REAR AXLE – Troubleshooting 27-22
INSPECTION PROCEDURE 3
AYC warning lamp does not light up when the ignition key
is turned to “ON” (engine stationary).
Probable cause
The lamp power supply circuit is probably open-circuited, lamp bulb is out, or the
circuit between AYC warning lamp and AYC-ECU or AYC-ECU itself is defective.
Blown fuse

AYC warning lamp out

Defective harness or connector

Defective AYC-ECU
NG
Check and repair the harness between
ignition switch (IG
2) and AYC warning
lamp.
OK
Check the trouble symptom.
OK
Replace combination meter.
NG
Check the harness between AYC
warning lamp and AYC-ECU.NG
Repair
OK
Check the trouble symptom.OK
Replace AYC-ECU.
OK
Check the following connectors:
B-96, B-94, B-08NG
Repair
OK
Measure at B-96 AYC-ECU connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Warning lamp when 36 is grounded
to body
OK:Lit upNGCheck the lamp bulb.NG
Replace
Measure at B-08 combination meter
connector.

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Voltage across 48 and body ground
OK:Symptom voltageNGCheck the following connectors:
B-08, B-74, B-76NG
Repair

REAR AXLE – Troubleshooting 27-25
DATA LIST REFERENCE TABLE
The following items can be read by t01he MUT-

from the ECU input data.
Item No.
Check itemChecking requirementsNormal value
01Front-right wheel speedPerform a test run.Vehicle speeds
displayed on the
02Front-left wheel speed
displayed on the
speedometer and
MUTIIare identi03Rear-right wheel speedMUT-II are identi-
cal.
04Rear-left wheel speed
05Front-right wheel speed
(0.2 km/h)
06Front-left wheel speed (0.2
km/h)
07Rear-right wheel speed
(0.2 km/h)
08Rear-left wheel speed (0.2
km/h)
10Vehicle speed
11System voltageIgnition switch: ONBattery voltage
15TPS openingAccelerator pedal position/Igni-
tion switch: ON
Fully closed300 – 1000mV
tion switch: ON
Partially openGradually increases
from the above val-
ue.
Fully open4500 – 5000mV
19Longitudinal acceleration
sensor
Vehicle stands on level ground2.4 – 2.6V
sensor
Perform a test run.Reading fluctuates
up or down with 2.5V
as its center.
20Lateral acceleration sensorVehicle stands on level ground2.4 – 2.6V
Perform a test run.Reading fluctuates
up or down with 2.5V
as its center.
22Steering wheel operationSteering wheel turning direction
Ignition switch: ON90 deg. clock-
wiseR90 deg
90 deg counter-
clockwiseL90 deg
23Steering wheel turning
angular velocity
Steering wheel position
Ignition switch: ON
Not turned0 deg/s
angular velocityIgnition switch: ON
TurnedReading varies ac-
cording to turning
speeds.
45Idle position switchAccelerator pedal position
Ignition position: ON
Not depressedON
Ignition position: ON
DepressedOFF