Mitsubishi Montero (2004+). Manual - part 305

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-707

DTC P1601: Communication Malfunction (between PCM and Throttle Actuator Control Module)

.

TECHNICAL DESCRIPTION

• PCM checks the communication lines for abnor-

mal conditions.

.

DESCRIPTIONS OF MONITOR METHODS
Communication with throttle actuator control module 

is impossible.

.

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

.

DTC SET CONDITIONS

Check Conditions

• Battery positive voltage is higher than 6.3 volts.

Judgement Criteria

• PCM detects an error in communication with the 

throttle actuator control module for 0.05 second.

• Throttle actuator control module detects an error 

in communication with the PCM for 0.125 sec-
ond.

.

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

• PCM failed.

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, read the diagnostic 
trouble code (DTC)

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) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK"(OFF) position.
Q: Is DTC P01601 set?

YES : Replace the PCM.
NO :  It can be assumed that this malfunction is intermittent. 

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

P.00-6

.

AK302970

AB

MB991911

MB991824

MB991827

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-708

DTC P1603: Battery Backup Line Malfunction

.

TECHNICAL DESCRIPTION

• The PCM is checks the open circuit of battery 

backup line.

NOTE: When the system detects an open circuit in 
the battery backup line, it makes 1 failure judgment 
of other diagnostic trouble codes (DTCs).

.

DESCRIPTIONS OF MONITOR METHODS
Battery backup line voltage is under specified value.

.

MONITOR EXECUTION
Continuous

.

AK201151

WHITE-BLA

CK

WHITE-BLA

CK

FUSIBLE
LINK(5)

58

BATTERY
BACKUP

POWERTRAIN CONTROL
MODULE (PCM)

6

Battery Backup Circuit

31

35363738394041 42 43
444546474849

50 51

5253

545556

57 58

32

33 34

D-133

(MU803803)

A-03

(MU802611)

1 2 3 4 5 6
7 8 9 10 11 12

AK201038

CONNECTOR: D-133

AC

PCM

D-133(GR)

AK201046

A-03(B)

AB

CONNECTOR: A-03

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-709

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

.

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• Engine starting sequence was completed.

• Battery positive voltage is higher than 10 volts.

Judgement Criteria

• Battery backup line voltage has continued to be 6 

volts or lower for 2 seconds.

.

OBD-II DRIVE CYCLE PATTERN
None.

.

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

• Open or shorted battery backup line, harness 

damage, or connector damage.

• PCM failed.

DIAGNOSIS

Required Special Tools:

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

START

MONITORING
CONDITIONS

CIRCUIT VOLTAGE

MALFUNCTION

CONTINUOUS

FAILURE FOR 2secs

NO

YES

YES

NO

< 6V

END

GOOD

NO

Yes

AK302959

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-710

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991911: Main Harness B

STEP 1. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).

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) Erase the DTC.
(4) Start the engine and run it at idle.
(5) Read the DTC.
(6) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P1603 set?

YES : Go to Step 2.
NO :  The inspection is complete.

STEP 2. Measure the backup power supply voltage at PCM 
connector D-133 by backprobing.
(1) Do not disconnect the PCM connector D-133.

(2) Measure the voltage between terminal No. 58 and ground 

by backprobing.

• Voltage should be battery positive voltage.

Q: Is battery positive voltage (approximately 12 volts) 

present?
YES : Go to Step 5.
NO :  Go to Step 3.

AK302970

AB

MB991911

MB991824

MB991827

AK200939

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

52

53

54

55

56

57

58

50

51

AB

CONNECTOR: D-133

HARNESS CONNECTOR: 
COMPONENT SIDE

PCM

D-133(GR)

AK201427

31

35363738394041 42 43
444546474849

50 51

5253

545556

57 58

32

33 34

AB

D-133 HARNESS 
CONNECTOR: 
HARNESS SIDE