1997 MITSUBISHI TRITON engine

AUTOMATIC TRANSMISSION ± Troubleshooting23-4
TROUBLESHOOTING23100760152
STANDARD FLOW OF DIAGNOSIS TROUBLESHOOTING
Automatic transmission malfunctions may be caused by the following conditions.
(1) Improper maintenance and adjustment
(2) Shift control system malfunction
(3) Mechanical malfunctions
(4) Hydraulic malfunctions
(5) Poor engine performance
Troubleshooting in the event of any such malfunctions should begin by checking fluid level, ATF condition,
manual linkage adjustment, throttle control cable adjustment and other conditions whose deviation from
standards can be readily known. Then, road test shall be performed to determine whether or not the
problem has been corrected or more diagnosis is necessary. If the problem still persists after these tests
and corrections, hydraulic tests should be performed for further troubleshooting.
Road test (guess what causes malfunc-
tion.)
Check how A/T works in each drive
range to find a defective system.
A/T control component inspection
Check the throttle cable, inhibitor switch,
overdrive switch, overdrive solenoid
valve, overdrive control relay, defective
switch, engine coolant temperature
switch and vehicle speed sensor.
Torque converter stall test (Inspection
of engine performance and mechanical
function)
Check the engine performance, torque
converter operation and clutch and
brake sliding performance.
Hydraulic pressure test (Inspection of
hydraulic control mechanism)
Measure the fluid line pressure and
check for malfunctions of the oil pump
or regulator valve and for oil leaks.
Oil leak inspection
Visually check gaskets and oil seals for
leaks.
Adjustment of basic inspection items
ROAD TEST 23100780158
Prior to performing road test, be sure to make basic checks including check and adjustment of fluid
level and condition and adjustment of the throttle cable. For road test, the transfer must be placed in
the 2H (2WD-high) position. In road test, various changes such as slips in transmission and shifting
conditions are checked and the transmission operation at each shift position must have been checked.

AUTOMATIC TRANSMISSION ± Troubleshooting23-5
D RANGE TEST
Correct
Carry out the TEST 1 again.
Ye s
Check the shifting points.Incorrect
Line pressure malfunction

Governor malfunction

Incorrect throttle cable adjustment
Ye s
Does the upshift from 3-speed to 4-speed occur? (with throttle
valve opening under 85%)No
3 ± 4 shift valve malfunction

Governor malfunction

Overdrive switch or overdrive solenoid malfunction

Overdrive control relay malfunction

Engine coolant temperature switch malfunction <4G6>
Ye s
Does the upshift from 2-speed to 3-speed occur?No
2 ± 3 shift valve malfunction

Governor malfunction
NG
Does the upshift from 1-speed to 2-speed occur?No
1 ± 2 shift valve malfunction

Governor malfunction
TEST 1
Start with throttle valve opened (50 % and full), and check upshift
from 1-speed  2-speed, 2-speed 3-speed and 3-speed 
4-speed. Check that shifting points match shift pattern.OKTEST 2
Correct
Carry out TEST 2 again.
Ye s
Check the shifting point.Incorrect
Line pressure malfunction

Governor malfunction

Detent regulator valve malfunction
NG
Does the downshift occur?No
Shift valves malfunction

Governor malfunction

Overdrive switch or overdrive solenoid malfunction

Overdrive control relay malfunction

Detection switch malfunction
TEST 2
Kickdown traveling at 2-speed, 3-speed and 4-speed. Check that
possible kickdown vehicle speed limit at 2-speed  1-speed,
3-speed  1-speed, 3-speed  2-speed, or 4-speed  1-speed,
4-speed  2-speed, 4-speed  3-speed conforms with the shift
pattern.OKTEST 3
Correct
Carry out TEST 3 again.
Ye s
Check the Shifting point.Incorrect
Incorrect throttle cable adjustment

Governor malfunction

Line pressure malfunction

Low coast modulator valve malfunction
NG
Does the downshift from 2-speed to 1-speed occur?No
1 ± 2 shift valve malfunction

Governor malfunction
TEST 3
When traveling in 3-speed or 4-speed, release accelerator pedal
and shift to L. Check that 3-speed  2-speed or 4-speed  3-speed
takes place immediately and 2-speed  1-speed downshift con-
forms with shift pattern.OKTEST 4

AUTOMATIC TRANSMISSION ± Troubleshooting23-6
Ye s
Carry out TEST 4 again.
Ye s
Does the engine brake function in L range?NoBrake No. 3 malfunction
No
Does the engine brake function in 2 range?NoBrake No. 1 malfunction
TEST 4
When traveling in 3-speed or 4-speed, shift to 2 and L. Does the
engine brake function in each range?Ye sTEST 5
Ye s

High line pressure

Accumulator malfunction

Check ball malfunctionCarry out TEST 5 again.
TEST 5
Is there abnormal noise(s) during acceleration and deceleration?
Is there shocks when slipping and changing speed?NoTEST 6
Ye s

Incorrect torque converter installation

Oil pump malfunction

Shifting gear not meshing correctly

Incorrect drive plate installationCarry out TEST 6 again.
TEST 6
Is there abnormal noise(s) or vibration when traveling in 3-speed
or 4-speed?NoTEST 7
NOTE
Abnormal noises and vibrations are often caused by an unbalanced propeller shaft, differential, tyre,
torque converter, engine, etc. Extremely thorough inspection is therefore required.
Ye s
Carry out TEST 7 again.
Ye s
Does lock up go on, off?No
Lock up signal valve malfunction

Lock up relay valve malfunction

Lock up clutch malfunction
No
Does the moment when lock up turns ON or OFF conform with
the shift pattern?No
Governor malfunction

Line pressure malfunction
TEST 7
Check that lock up ON, OFF. Does the shifting points conform
with shift pattern?Ye sCarry out the road test in 2 range.
NOTE
(1) Determine the moment when lock up turns ON by decreased engine r/min or by a slight shock back
and forth.
(2) Determine the moment when lock up turns OFF by increased engine r/min.
(3) Check lock up condition by pumping the accelerator slightly. If engine r/min rises in accordance with
throttle valve opening size, determine that the lock up is OFF, if not, determine it ON.
(When lock up is OFF, drive power is transferred through the fluid in the torque converter and therefore,
when the accelerator pedal is depressed, slipping occurs inside the torque converter with a resulting
large increase in engine r/min.)

AUTOMATIC TRANSMISSION ± Troubleshooting23-7
2 RANGE TEST
Correct
Carry out TEST 1 again.
Ye s
Check the shifting point.Incorrect
Misadjusted throttle cable

Governor malfunction

Line pressure malfunction
No
Does the upshift from 1-speed to 2-speed occur?No
1 ± 2 shift valve malfunction

Governor malfunction
TEST 1
Start with throttle valve opening at 50% and full. Does the shifting
points conform with the shift pattern when upshifting from 1-speed

2-speed?Ye sTEST 2
Ye s
Carry out TEST 2 again.
NG
Does the downshift occur and is the shifting point correct?No
Detent regulator valve malfunction

Governor malfunction

Misadjusted throttle cable

1 ± 2 shift valve malfunction

Line pressure malfunction
TEST 2
Kickdown and check that possible kickdown vehicle speed limit
at 2-speed
1-speed conforms with shift pattern.OKCarry out road test in L range.
L RANGE TEST
No
Carry out road test in R range.
TEST 1
Does the transmission upshift to 2-speed?Ye s
Low coast modulator valve malfunction

Governor malfunction

Low line pressure
R RANGE TEST
Ye s
Carry out road test in P range.
TEST 1
Is the engine r/min by stall test correct?No
Brake No. 3 malfunction

Overdrive clutch or direct clutch malfunction

Overdrive one-way clutch malfunction

Low line pressure
P RANGE TEST
Ye s
End
TEST 1
Park vehicle on an incline (more than 5) and release parking
and service brakes. Does the vehicle move?No
Park mechanism malfunction

Misadjusted shift lever

AUTOMATIC TRANSMISSION ± On-vehicle Service23-19
CONVERTER STALL TEST 23100540138
In this test, the engine maximum speed when the
torque converter stalls with the shift lever in the
ªDº or ªRº range is measured to check operation
of the torque converter, starter and one-way clutch
and check holding performance of the transmission
clutch (including brake).
Caution
Do not stand in front or at rear of the vehicle
during this test.
(1) Check the transmission fluid level. The fluid
temperature should be at the level after normal
operation (70 ± 80
C). The engine coolant
temperature should also be at the level after
normal operation (80 ± 90
C).
(2) Apply chocks to the rear wheels (right and left).
(3) Mount an engine tachometer.
(4) Apply fully the parking and service brakes.(5) Start the engine.
(6) With the selector lever in the ªDº range, fully
depress the accelerator pedal and read off the
engine maximum speed.
Standard value:
2,100 ± 2,400 r/min <4G63>
2,300 ± 2,600 r/min <4D56>
NOTE
When doing so, do not keep the engine running
with throttle full open for more than 5 seconds.
If two or more stall tests are needed, place
the selector lever in the ªNº position and run
the engine at about 1,000 r/min to allow the
transmission fluid to cool before another stall
test.
(7) Place the selector lever in the ªRº range and
perform the test as above.
JUDGEMENT OF STALL TEST RESULTS
Stall speed in ªDº and ªRº range is equal to each other
but lower than the nominal value.(1) Engine output is low.
(2) Starter one-way clutch is faulty. (Faulty torque
converter is suspected if it is lower than nominal
by more than 600 r/min)
Stall speed in ªDº range is higher than nominal.(1) Overdrive clutch slipping
(2) Overdrive one-way clutch faulty
(3) Forward clutch slipping
(4) One-way clutch No. 2 faulty
(5) Low line pressure
Stall speed in ªRº range is higher than nominal.(1) Overdrive clutch slipping
(2) Overdrive one-way clutch faulty
(3) Direct clutch slipping
(4) Brake No. 3 slipping
(5) Low line pressure

ABS <2WD> ± Troubleshooting35B-5
TROUBLESHOOTING35201110143
STANDARD FLOW OF DIAGNOSTIC TROUBLESHOOTING
Refer to GROUP 00 ± How to Use Troubleshooting/Inspection Service Points.
NOTES WITH REGARD TO DIAGNOSIS
The phenomena listed in the following table are not abnormal.
PhenomenonExplanation of phenomenon
System check soundWhen starting the engine, a thudding sound can sometimes be heard coming from inside
the engine compartment, but this is because the system operation check is being
performed, and is not an abnormality.
ABS operation sound1. Sound of the motor inside the ABS hydraulic unit operation. (whine)
2. Sound is the generated along with vibration of the brake pedal. (scraping)
3. When ABS operates, sound is generated from the vehicle chassis due to repeated
brake application and release.
(Thump: suspension; squeak: tyres)
ABS operation
(Long braking distance)For road surfaces such as snow-covered roads and gravel roads, the braking distance for
vehicles with ABS can sometimes be longer than that for other vehicles. Accordingly, advise
the customer to drive safely on such roads by lowering the vehicle speed and not being too
overconfident.
Shock during system
operation checkShock may be felt when the brake pedal is depressed slightly at a low driving speed. This
occurs due to ABS operation check (initial check at a vehicle speed of 8 km/h), and does
not indicate any malfunction.
Diagnosis detection condition can vary depending on the diagnosis code.
Make sure that checking requirements listed in the ªCommentº are satisfied when checking the trouble
symptom again.
DIAGNOSIS FUNCTION35201120108
DIAGNOSIS CODES CHECK
Read a diagnosis code by the MUT-II or ABS warning lamp.
(Refer to GROUP 00 ± How to Use Troubleshooting/Inspection
Service Points.)
ERASING DIAGNOSIS CODES
Refer to GROUP 00 ± How to Use Troubleshooting/Inspection
Service Points.

ABS <2WD> ± Troubleshooting35B-8
Code No. 15 Wheel speed sensor (Abnormal output signal)Probable cause
A wheel speed sensor outputs an abnormal signal (other than an open or short-circuit).
Improper installation of wheel speed sensor

Malfunction of wheel speed sensor

Malfunction of rotor

Malfunction of wheel bearing

Malfunction of wiring harness or connector

Malfunction of ABS-ECU
NG
Replace the ABS-ECU.
OK
Check trouble symptoms.
OK
Wheel bearing check. (Refer to GROUP
26 and 27 ± On-vehicle Service.)OKCheck the harness wire between each
wheel speed sensor and ABS-ECU, and
repair if necessary.
OK
Rotor check. (Refer to P.35B-40.)NGReplace the rotor.
OK
Check the following connector.
C-62NG
Repair
OK
Wheel speed sensor output voltage
check (Refer to P.35B-24.)NGWheel speed sensor check. (Refer to
P.35B-39.)NGReplace the wheel speed sensor.
Wheel speed sensor installation check.NG
Repair
Code No. 16 Power supply systemProbable cause
The voltage of the ABS-ECU power supply drops lower or rises higher than the specified
value. If the voltage returns to the specified value, this code is no longer output.
Malfunction of wiring harness or connector.

Malfunction of ABS-ECU
Caution
If battery voltage drops or rises during inspection, this code will be output as well. If the voltage
returns to standard value, this code is no longer output.
Before carrying out the following inspection, check the battery level, and refill distilled water if
necessary.
OK
Check the battery.
OK
Check trouble symptoms.NGCheck the harnes wire between the igni-
tion switch and the ABS-ECU, and repair
if necessary.
OK
Check trouble symptoms.NGReplace the ABS-ECU.
OK
Check the following connector.
C-62NG
Repair
Measure at the ABS-ECU connector
C-62.

Disconnect the connector and
measure at the harness side.

Start the engine. Voltage between
13 ± Body earth
OK:System voltageNGCheck the following connectors.
C-88, C-86 and C-02NG
Repair

ABS <2WD> ± Troubleshooting35B-12
Code No. 53 Motor relay, motorProbable cause
These codes are output at the following times:
When the motor relay is on but no signal is input to the motor monitor line (motor
is not operating, etc.)
When the motor relay is off but a signal is input to the motor monitor line for 5 seconds
or more (motor continues operating, etc.)
When the motor relay does not operate
Malfunction of motor relay

Malfunction of wiring harness or connector

Malfunction of hydraulic unit

Malfunction of ABS-ECU
Caution
Because force-driving of the motor by means of the actuator test will drain the battery, the engine
should be started and left to run for a while after testing is completed.
NG
Repair
MUT-II Actuator test
Is the sound of the motor operating
heard for items 01 ± 03 only?Ye sCheck the harness between the hydrau-
lic unit and ABS-ECU, and repair if nec-
essary.
No
ABS motor relay check. (Refer to
P.35B-28.)NGReplace the motor relay.
OK
Measure at motor relay connector A-38.

Disconnect the connector and
measure at the harness side.

Voltage between 5 ± body earth
OK:System voltageNGCheck the harness between fusible link
No. 11 and ABS motor relay, and repair
if necessary.
OK
Measure at ABS-ECU connectors C-62
and C-64.

Disconnect the connector and
measure at the harness side.

Resistance between 26 ± 38
OK:72 ± 88 WNGCheck the following connector.
A-38
OK
Check trouble symptoms.NGCheck the harnesses between motor
relay and ABS-ECU, and repair if
necessary.
OK
Measure at ABS-ECU connector C-64.

Disconnect the connector and
measure at the harness side.

Continuity between 49 ± body earth
OK:ContinuityNGCheck the harness between the
hydraulic unit and ABS-ECU, and repair
if necessary. Motor earth, repair if
necessary.
OK
Motor operation check. (Refer to
P.35B-27.)NGReplace the hydraulic unit.
OK
Check the following connector.
C-64NG
Repair
OK
Check trouble symptoms.NGReplace the ABS-ECU.