Mitsubishi Montero (2002-2004). Manual - part 689

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-453

AC203992

Fuel Tank Differential Pressure Sensor Circuit

AB

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-454

.

CIRCUIT OPERATION

• The PCM (terminal 97) supplies a 5-volt refer-

ence signal to the fuel tank differential pressure 
sensor (terminal 3). The fuel tank differential 
pressure sensor (terminal 2) is grounded through 
the PCM (terminal 96).

• The fuel tank differential pressure sensor (termi-

nal 1) returns a voltage signal to the PCM (termi-
nal 82) that is proportional to the pressure in the 
fuel tank.

.

TECHNICAL DESCRIPTION

• The PCM monitors the fuel tank differential pres-

sure sensor output voltage.

• The PCM determines whether the fuel tank differ-

ential pressure sensor signal voltage is within 
normal operating parameters.

.

DTC SET CONDITIONS

Test Conditions: 

• Intake air temperature is greater than 5°C (41°F).

• Engine speed is greater than 1,600 r/min.

• Volumetric efficiency is between 25 and 80 per-

cent.

Judgment Criteria:

• When the evaporative emission purge solenoid is 

off, the fuel differential pressure sensor output 
voltage remains at 1.0 volt or less for ten sec-
onds.

.

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

• Malfunction of the fuel tank differential pressure 

sensor.

• A damaged harness in the fuel tank differential 

pressure sensor circuit.

• Malfunction of the PCM.

AC203998

CONNECTOR: D-112

AB

D-112

AC203993

CONNECTORS: D-134, D-135

AB

D-134
(GR)

D-135
(GR)

PCM

AC203999

CONNECTORS: E-111, E-113

AB

E-113

E-111

AC204000

CONNECTOR: F-07

AB

F-07 (B)

ACX00218

CONNECTOR : G-05

AQ

G-05 (B)

SECOND SEAT UNDER
SERVICE HOLE

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-455

.

OVERVIEW OF TROUBLESHOOTING

•  DTC P0452 can be set by a faulty fuel tank differ-

ential pressure sensor or related circuit, or PCM 
failure.

• To check a system blockage, do a performance 

test which uses a mechanical vacuum gauge and 
scan tool MB991502 set on the fuel tank differen-
tial pressure sensor (TANK PRS SNSR 73).

The mechanical gauge reading is used to verify 
scan tool MB991502 reading.
A comparison of the mechanical gauge with the 
reading on scan tool MB991502 will locate a 
problem in the system.

DIAGNOSIS

Required Special Tools:

• MB991502: Scan Tool (MUT-II)

• MB991658: Test Harness Set

STEP 1. Using scan tool MB991502, check data list item 73: 
Fuel Tank Differential Pressure Sensor.

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.

(2) Disconnect hose F from the evaporative emission canister 

side, and plug the hose.

(3) Turn the ignition switch to the "ON" position.
(4) Remove the fuel cap.
(5) Set scan tool MB991502 to the data reading mode for item 

73, Fuel Tank Differential Pressure Sensor.

• The fuel tank pressures reading on the scan tool should 

be 

−3.3 to 3.3 kPa (−0.97 to 0.97 inHg).

(6) Connect an evaporative emission system pressure pump to 

the fuel tank filler tube and pressurize the fuel tank.

• The fuel tank pressure reading should increase.

(7) Disconnect an evaporative emission system pressure pump 

and connect hose F.

(8) Turn the ignition switch to the "LOCK" (OFF) position and 

disconnect scan tool MB991502.

Q: Is the fuel tank pressure between 

−3.3 and 3.3 kPa (−

0.97 and 0.97 inHg)?
YES : It can be assumed that this malfunction is intermittent. 

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

− How to Cope with 

Intermittent Malfunction 

P.00-6

). Go to Step 15.

NO :  Go to Step 2.

ACX01539

16-PIN

MB991502

AC

AC102602 AC

HOSE F

ACX01358

TSB Revision

DIAGNOSTIC TROUBLE CODE PROCEDURES

13Ac-456

STEP 2. Measure the signal voltage at fuel tank differential 
pressure sensor connector G-05.
(1) Tumble the second seat.
(2) Remove the service hole cover (upper) and packing.
(3) Remove the service hole cover (lower) and packing.
(4) Disconnect fuel tank differential pressure sensor connector 

G-05.

(5) Connect special tool MB991658 between fuel tank 

differential pressure sensor connector G-05 terminals 1, 2 
and 3.

(6) Turn the ignition switch to the "ON" position.
(7) Remove the fuel cap.
(8) Measure the voltage between fuel tank differential pressure 

sensor connector G-05 terminal 1 and ground.

• The voltage should measure between 2.0 and 3.0 volts.

(9) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 2.0 and 3.0 volts?

YES : Go to Step 10.
NO :  Go to Step 3.

STEP 3. Measure the 5-volt reference signal at fuel tank 
differential pressure sensor connector G-05.
(1) Disconnect fuel tank differential pressure sensor connector 

G-05.

(2) Connect special tool MB991658 between fuel tank 

differential pressure sensor connector G-05 terminals 1, 2 
and 3.

(3) Turn the ignition switch to the "ON" position.
(4) Measure the voltage between fuel tank differential pressure 

sensor connector G-05 terminal 3 and ground.

• The voltage should measure between 4.8 and 5.2 volts.

(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.8 and 5.2 volts?

YES : Go to Step 8.
NO :  Go to Step 4.

ACX00218

CONNECTOR : G-05

AS

G-05 (B)

SERVICE HOLE (UPPER)

G-05 HARNESS
CONNECTOR:
COMPONENT SIDE

1

2

3

SERVICE HOLE (LOWER)

AC002081AB

MB991658

FUEL TANK DIFFERENTIAL 
PRESSURE SENSOR

ACX00218

CONNECTOR : G-05

AR

G-05 (B)

SECOND SEAT UNDER
SERVICE HOLE

G-05 HARNESS
CONNECTOR:
COMPONENT SIDE

1

2

3

AC002081AB

MB991658

FUEL TANK DIFFERENTIAL 
PRESSURE SENSOR