Mitsubishi Montero Sport (2004+). Manual - part 179

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-129

.

CIRCUIT OPERATION

• 5-volt voltage is applied to the engine coolant 

temperature sensor output terminal (terminal No. 
1) from the PCM (terminal No. 44) via the resistor 
in the PCM. The ground terminal (terminal No. 2) 
is grounded with (terminal No. 57).

• The engine coolant temperature sensor is a neg-

ative temperature coefficient type of resistor. It 
has the characteristic that when the engine cool-
ant temperature rises the resistor decreases.

• The engine coolant temperature sensor output 

voltage increases when the resistor increases 
and decreases when the resistor decreases.

.

TECHNICAL DESCRIPTION

• The engine coolant temperature sensor converts 

the engine coolant temperature to a voltage and 
output it.

• The PCM checks whether this voltage is within a 

specified range.

.

DESCRIPTIONS OF MONITOR METHODS
Engine coolant temperature sensor output voltage is 

out of specified range.

.

MONITOR EXECUTION
Continuous

.

MONITOR EXECUTION CONDITIONS (Other 
monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Not applicable

.

AK103912AB

CONNECTOR: C-71

C-71

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-130

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• 2 seconds or more have passed since the staring 

sequence was completed.

Judgement Criteria

• Engine coolant temperature sensor output volt-

age has continued to be 4.6 volts or higher [cor-
responding to coolant temperature of 

−45°C 

(

−49°F) or lower] for 2 seconds.

.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function

−OBD-II Drive 

Cycle

−Procedure 6−Other Monitor 

P.13A-4

.

.

TROUBLESHOOTING HINTS (The most likely 
causes for this code to be set are:)

• Engine coolant temperature sensor failed.

• Open engine coolant temperature sensor circuit, 

or connector damage.

• PCM failed.

START

OUTPUT VOLTAGE > 4.6V

OUTPUT VOLTAGE < 0.1V

END

NO

NO

NO

YES

YES

YES

MALFUNCTION

GOOD

CONTINUOUS

FAILURE FOR 2secs

MONITORING

CONDITIONS?

NO

YES

AK301426

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-131

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I

• MB991827: USB Cable

• MB991911: Main Harness B

STEP 1. Using scan tool MB991958, check data list item 21: 
Engine Coolant Temperature Sensor.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to the data reading mode for item 

21, Engine Coolant Temperature Sensor.

• The engine coolant temperature and temperature 

shown with the scan tool should approximately match.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?

YES : It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

P.00-7

.

NO :  Go to Step 2.

STEP 2. Check connector A-67 at the engine coolant 
temperature sensor for damage.
Q: Is the connector in good condition?

YES : Go to Step 3.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 11.

AK303629AB

MB991911

MB991827

MB991824 

16-PIN

AK104023

1

2

A-67(B)

AB

CONNECTOR: A-67

HARNESS 
CONNECTOR: 
COMPONENT SIDE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-132

STEP 3. Measure the sensor supply voltage at engine 
coolant temperature sensor harness side connector A-67.
(1) Disconnect the connector A-67 and measure at the harness 

side.

(2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 1 and ground.

• Voltage should be between 4.5 and 4.9 volts.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.5 and 4.9 volts?

YES : Go to Step 7.
NO :  Go to Step 4.

STEP 4. Measure the sensor supply voltage at PCM 
connector C-90 by backprobing.
(1) Do not disconnect the PCM connector C-90.
(2) Disconnect the engine coolant temperature sensor 

connector C-90.

(3) Turn the ignition switch to the "ON" position.

(4) Measure the voltage between terminal No. 44 and ground 

by backprobing.

• Voltage should be between 4.5 and 4.9 volts.

(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.5 and 4.9 volts?

YES : Go to Step 5.
NO :  Go to Step 6.

AK104023

1

2

A-67(B)

AB

CONNECTOR: A-67

HARNESS 
CONNECTOR: 
COMPONENT SIDE

AK000234

A-67 HARNESS 
CONNECTOR: 
COMPONENT SIDE

2 1

AO

AK103762

42

43

48

49

50

51

52

53

54

55

56

57

46 45 44

58

59

60

61

62

63

64

65

66

47

41

AB

CONNECTOR: C-90

C-90(GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AKX01527

AKX01527

545556

46

45

44

58 59

60616263

646566

47

41 42 43

48 4950

57

515253

AKX01527AD

C-90 HARNESS 
CONNECTOR: 
HARNESS SIDE