Mitsubishi Montero Sport (2004+). Manual - part 97

STARTING SYSTEM

TSB Revision

ENGINE ELECTRICAL

16-29

OVERRUNNING CLUTCH CHECK
1. While holding the clutch housing, rotate the pinion. The drive 

pinion should rotate smoothly in one direction, but should 
not rotate in opposite direction. If the clutch does not 
function properly, replace the overrunning clutch assembly.

2. Inspect the pinion for wear or burrs. If the pinion is worn or 

burred, replace the overrunning clutch assembly. If the 
pinion is damaged, also inspect the ring gear for wear or 
burrs.

.

FRONT AND REAR BRACKET BUSHING CHECK
Inspect the bushing for wear or burrs. If the bushing is worn or 
burred, replace the front bracket assembly or rear bracket 
assembly.

.

ARMATURE CHECK
1. Check that the armature coil is not grounded.
2. Place the armature in a growler.
3. Hold a thin steel blade parallel and just above while rotating 

the armature slowly in the growler. A shorted armature will 
cause a blade to vibrate and be attracted to the core. 
Replace the shorted armature.

4. Check the insulation between the armature coil cores and 

the commutator segments. They are normal if there is no 
continuity.

5. Check for continuity between the segments. The condition is 

normal if there is continuity.

AKX00378

FREE

LOCK

AB

AKX00379

GROWLER

AB

AKX00380

AKX00381

IGNITION SYSTEM

TSB Revision

ENGINE ELECTRICAL

16-30

IGNITION SYSTEM

GENERAL DESCRIPTION

M1163000100302

This system is provided with three ignition coils (A, B 
and C) and three ignition power transistors (A, B and 
C) for the number 1 and number 4 cylinders, number 
2 and number 5 cylinders and number 3 and number 
6 cylinders, respectively. 
Interruption of the primary current flowing in the pri-
mary side of ignition coil A generates a high voltage 
in the secondary side of ignition coil A.
The high voltage thus generated is applied to the 
spark plugs of number 1 and number 4 cylinders to 
generate sparks. At the time that the sparks are gen-
erated at both spark plugs, if one cylinder is at the 
compression stroke, the other cylinder is at the 
exhaust stroke, so that ignition of the compressed 
air/fuel mixture occurs only for the cylinder which is 
at the compression stroke.
In the same way, when the primary current flowing in 
ignition coil B is interrupted, the high voltage thus 
generated is applied to the spark plugs of number 2 
and number 5 cylinders, and when the primary cur-
rent flowing in ignition coil C is interrupted, the high 
voltage thus generated is applied to the spark plugs 
of number 3 and number 6 cylinders. 

The powertrain control module (PCM) controls the 
three ignition power transistors (A, B and C) to turn 
them alternately ON and OFF. This causes the pri-
mary currents in the ignition coils (A, B and C) to be 
alternately interrupted and allowed to flow to fire the 
cylinders in the order 1-2-3-4-5-6.
The PCM determines which ignition coil should be 
controlled by means of the signals from the camshaft 
position sensor which is incorporated in the camshaft 
and from the crankshaft position sensor which is 
incorporated in the crankshaft. 
It also detects the crankshaft position to provide igni-
tion at the most appropriate timing in response to the 
engine operation conditions.
When the engine is cold or operated at high alti-
tudes, the ignition timing is slightly advanced to pro-
vide optimum performance.

AK301846

IGNITION POWER
TRANSISTOR UNIT

IGNITION COIL

SPARK PLUGS

CYLINDER NO.

B

C

A

A

1

4

2

5

3

6

B

C

AB

INTAKE AIR TEMPERATURE SENSOR

BAROMETRIC PRESSURE SENSOR

CAMSHAFT POSITION SENSOR

CRANKSHAFT POSITION SENSOR

TRANSMISSION RANGE SWITCH

IGNITION SWITCH-ST

KNOCK SENSOR 

ENGINE COOLANT TEMPERATURE
SENSOR

VOLUME AIRFLOW SENSOR

PCM

IGNITION SYSTEM

TSB Revision

ENGINE ELECTRICAL

16-31

SPECIAL TOOLS

M1163000600307

ON-VEHICLE SERVICE

SPARK PLUG CABLE TEST

M1163000900096

WARNING

Wear rubber gloves while performing this test.

1. Disconnect, one at a time, each of the spark plug cables 

while the engine is idling to check whether the engine's 
running performance changes or not.

2. If the engine performance does not change, check the 

resistance of the spark plug cable, and check the spark plug 
itself.

SPARK PLUG TEST

M1163001500109

1. Remove the spark plug and connect to the spark plug cable.

2. Ground the spark plug outer electrode (body), and crank the 

engine.
Check that there is an electrical discharge between the 
electrodes at this time.

TOOL

TOOL NUMBER AND 
NAME

SUPERSESSION

APPLICATION

MB991348
Test harness set

MB991348-01

Inspection of ignition 
primary voltage (ignition 
power transistor 
connection)

MB991348

AKX00431

SPARK PLUG CABLE

AB

AKX00432

SPARK PLUG

AB

AKX00277

DEFECTIVE INSULATION

DEFECTIVE INSULATION

DEFECTIVE
INSULATION

GOOD

AB

IGNITION SYSTEM

TSB Revision

ENGINE ELECTRICAL

16-32

IGNITION COIL CHECK

M1163001200335

1. Measurement of the primary coil resistance

Measure the resistance between each ignition coil terminal.

Standard value:0.74 

− 0.90 Ω

2. Measurement of the secondary coil resistance

Measure the resistance between each ignition coil 
high-voltage terminal.

Measurement points

• Number 3 and Number 6 cylinder side coil... A coil

• Number 1 and Number 4 cylinder side coil... B coil

• Number 2 and Number 5 cylinder side coil... C coil

Standard value: 20.1 

− 27.3 kΩ

IGNITION POWER TRANSISTOR CONTINUITY 
CHECK

M1163001300138

NOTE: An analog-type ohmmeter should be used.
As described in the chart below, perform a continuity check on 
the ignition power transistor.
Number 1 and Number 4 cylinder side coil

Number 2 and Number 5 cylinder side coil

AKX00272

AKX00273

A

B

C

AB

1.5 V POWER SUPPLY
BETWEEN 3 

− 4

CONTINUITY BETWEEN 
4 

− 13

Current flowing

Yes

Current not flowing

No

1.5 V POWER SUPPLY
BETWEEN 2 

− 4

CONTINUITY BETWEEN 
4 

− 12

Current flowing

Yes

Current not flowing

No

AKX00274

11 12 13

1 2 3 4 5 6

1.5 V

+

+

-

-

AB

AKX00275

11 12 13

1 2 3 4 5

6

1.5 V

+

+

-

-

AB