Mitsubishi Outlander XL. Manual - part 326

DTC SET CONDITIONS

Logic Flow Chart

ZK603435

Start

Off-idling condition

Idling condition?

F1 = 0

Off-idling condition

Yes

No

F2 = F2 + 1

End

No

Malfunction

F1 > 20

F2 > 8

FTPS output Voltage Fluctuation

> 0.2v

No 

Yes

Yes

F1 = F1 + 1

Good

Logic Flow Chart

No

Yes

Yes

No

Yes

No

AA00

Check Conditions

｠

Throttle valve is closed.

｠

Vehicle speed is 1.5 km/h (0.93 mph) or less.

Judgement Criteria

MULTIPORT INJECTION SYSTEM (MFI) <DIAGNOSIS>

13Ab-499

DIAGNOSTIC TROUBLE CODE PROCEDURES

｠

If the voltage signal from the fuel tank differential
pressure sensor changes by 0.2 volt or more, DTC
P0451 will set. The code may also set if a sudden
pressure fluctuation occurs twenty times while the
engine  is  idling,  and  then  four  consecutive  times
during normal driving.

NOTE: 

If the number of sudden pressure

fluctuations does not reach twenty during any
one period of engine idling, or if the ignition
switch is turned OFF, the counter will reset to
zero.

NOTE: 

The conditions for deviating from idling

operation are as follows:

｠

Vehicle speed is 50 km/h (31 mph) or greater.

OBD-ll DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-ll Drive Cycle -
Pattern 16 P.13Ab-8.

TROUBLESHOOTING HINTS (THE MOST LIKELY
CAUSES FOR THIS CODE TO BE SET ARE:)

｠

Connector damage.

｠

Harness damage.

｠

Fuel tank differential pressure sensor failed.

｠

ECM failed.

OVERVIEW OF TROUBLESHOOTING

｠

DTC  P0451  can  be  set  by  a  faulty  fuel  tank
differential  pressure  sensor  or  related  circuit,  or
ECM failure.

｠

To check for system blockage, do a performance
test which uses a mechanical vacuum gauge and
scan tool MB991958 set on the fuel tank differential
pressure  sensor  (TANK  PRS  SNSR  73).  The
mechanical  gauge  reading  is  used  to  verify  scan
tool  MB991958  reading.  A  comparison  of  the
mechanical  gauge  with  the  reading  on  scan  tool
MB991958 will locate a problem in the system.

 

DIAGNOSIS

Required Special Tools:

｠

MB991958: Scan Tool (M.U.T.-III Sub Assembly)

｠

MB991824: V.C.I.

｠

MB991827: M.U.T.-III USB Cable

｠

MB991910: M.U.T.-III Main Harness A

｠

MB992110: Power Plant ECU Check Harness

13Ab-500

MULTIPORT INJECTION SYSTEM (MFI) <DIAGNOSIS>

DIAGNOSTIC TROUBLE CODE PROCEDURES

STEP 1. Using scan tool MB991958, check data list item 52:
Fuel Tank Differential Pressure Sensor.

ZC501967

AC404789

ZC501968

MB991824

MB991827

MB991910

Data link

connector

AA00

To prevent damage to scan tool MB991958, always turn the
ignition  switch  to  the  "LOCK"  (OFF)  position  before
connecting or disconnecting scan tool MB991958.

(1)

Connect scan tool MB991958 to the data link connector.

ZK603402

Hose C

Plug

AA00

(2)

Disconnect hose C from the evaporative emission canister,
and plug the hose.

(3)

Turn the ignition switch to the "ON" position.

(4)

Remove the fuel cap.

(5)

Set scan tool MB991958 to the data reading mode.

｠

Item 52, Fuel Tank Differential Pressure Sensor.

｠

The fuel tank pressure reading on the scan tool should
be 2050 to 2950 mV.

ZK603403AA00

(6)

Connect  the  evaporative  emission  system  pressure  pump
(Miller number 6872A) to the fuel tank filler tube by using fuel
tank adapter (MLR-8382) and pressurize the fuel tank.

｠

The fuel tank pressure reading should increase.

(7)

Turn the ignition switch to the "LOCK" (OFF) position. Then
disconnect scan tool MB991958.

(8)

Remove  the  evaporative  emission  system  pressure  pump
(Miller number 6872A) and the fuel tank adapter (MLR-8382),
and reinstall the fuel cap.

(9)

Connect hose C to the evaporative emission canister.

Q:Is the fuel tank pressure between 2,050 and 2,950 mV?

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 Malfunctions P.00-15).

NO:

 Go to Step 2.

MULTIPORT INJECTION SYSTEM (MFI) <DIAGNOSIS>

13Ab-501

DIAGNOSTIC TROUBLE CODE PROCEDURES

STEP 2. Check harness connector B-11 at ECM and harness
connector D-19 at fuel tank differential pressure sensor for
damage.

Q:Is the harness connector in good condition?

YES:

 Then go to Step 3.

NO:

 Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection P.00E-2. Then go to Step 7.

STEP 3. Measure the 5-volt reference signal at fuel tank
differential pressure sensor connector D-19.

(1)

Remove the second seat assembly (Refer to GROUP 52A,
Second Seat Assembly P.52A-21).

ZK603415

Floor inspection lid (LH)

AA00

(2)

Remove the floor inspection lid (LH).

(3)

Disconnect fuel tank differential pressure sensor connector
D-19.

(4)

Turn the ignition switch to the "ON" position.

ZK603416

1

2

3

AA00

D-19 Harness
connector:
component side 

(5)

Measure the voltage between terminal 3 and ground.

｠

The voltage should measure between 4.9 and 5.1 volts.

(6)

Turn the ignition switch to the "LOCK" (OFF) position.

Q:Is the measured voltage between 4.9 and 5.1 volts?

YES:

 Go to Step 5.

NO:

 Go to Step 4.

STEP 4. Measure the 5-volt reference signal at ECM
connector B-11 by using check harness special tool
MB992110.

ECM

ZK603234AA00

Body side harness 

MB992110

(1)

Disconnect  all  ECM  connectors.  Connect  the  power  plant
ECU  check  harness  special  tool  MB992110  between  the
separated connectors.

(2)

Turn the ignition switch to the "ON" position.

(3)

Remove the fuel cap.

13Ab-502

MULTIPORT INJECTION SYSTEM (MFI) <DIAGNOSIS>

DIAGNOSTIC TROUBLE CODE PROCEDURES