Mitsubishi 380. Manual - part 573

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-384

DIAGNOSIS

Required Special Tools:

• Diagnostic tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

STEP 1. Check for exhaust leak.

Q: Are there any abnormalities?

YES : Repair it. Then go to Step 3.
NO :  Go to Step 2.

STEP 2. Using diagnostic tool, check data list item AD: 
Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).

CAUTION

To prevent damage to diagnostic tool, always turn the igni-
tion switch to the "LOCK" (OFF) position before connect-
ing or disconnecting diagnostic tool .
(1) Connect diagnostic tool  to the data link connector.
(2) Start the engine and run at idle.
(3) Set diagnostic tool  to the data reading mode for item AD, 

Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).

• Warming up the engine. When the engine is revved, the 

output voltage should repeat 0 volt and 0.6 to 1.0 volt 
alternately.

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

Q: Is the sensor operating properly?

YES : Go to Step 3.
NO :  Refer to DTC P0136 

− Heated Oxygen Sensor Circuit 

(Bank 1, Sensor 2) 

P.13A-186

, DTC P0137 

− Heated 

Oxygen Sensor Circuit Low Voltage (Bank 1, Sensor 
2) 

P.13A-192

, DTC P0138 

− Heated Oxygen Sensor 

Circuit High Voltage (Bank 1, Sensor 2) 

P.13A-198

, 

DTC P0139 

− Heated Oxygen Sensor Circuit Slow 

Response (Bank 1, Sensor 2) 

P.13A-203

.

STEP 3. Test the EOBD drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− EOBD Drive Cycle −

P.13A-11

.

(2) Read the diagnostic trouble code.

Q: Is DTC P0421 set?

YES : Replace the right bank side catalytic converter. 
NO :  The inspection is complete.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-385

DTC P0431: Warm Up Catalyst Efficiency Below Threshold (bank 2)

.

TECHNICAL DESCRIPTION

• The signal from the rear heated oxygen sensor 

differs from the front heated oxygen sensor. That 
is because the catalytic converter purifies 
exhaust gas. When the catalytic converter has 
deteriorated, the signal from the front heated oxy-
gen sensor becomes similar to the rear heated 
oxygen sensor.

• The ECU compares the output of the front and 

rear heated oxygen sensor signals.

.

DTC SET CONDITIONS

Check Conditions

• Lambda control upstream catalyst is active.

• Downstream oxygen sensor ready for operation.

• Lambda controller does not reache MIN/MAX 

limit.

• P-part of lambda control downstream is active.

• Neutralization of catalyst oxygen stroge is not 

active.

• No misfire.

• Transient control is not active.

• Active charcoal is not highly charged.

• No rapid load changes.

• Catalyst load within range.

• Load is between 14 and 30% <M/T> or 16 and 

38% <A/T>.

• Engine speed is between 1080 and 2480 r/min 

<M/T> or 1120 and 2480 r/min <A/T>.

• Catalyst temperature is between 580 and 780 

degreeC <M/T> or 535 and 730 degreeC <A/T>.

Judgment Criteria

• calculated aeging value (based on the sensor 

signal ratio) exceeds 0.55.

• MIL activated after 2 drive cycles.

• No Limp home.

.

EOBD DRIVE CYCLE PATTERN

Refer to Diagnostic Function 

− EOBD Drive Cycle − 

P.13A-11

.

.

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

• Left bank side catalytic converter deteriorated.

• Exhaust leak.

• Refer to component locations GROUP-

70

• Refer to configuration diagrams GROUP-

80

• Refer to circuit diagrams GROUP-

90

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-386

DIAGNOSIS

Required Special Tools:

• Diagnostic tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

STEP 1. Check for exhaust leak.

Q: Are there any abnormalities?

YES : Repair it. Then go to Step 3.
NO :  Go to Step 2.

STEP 2. Using diagnostic tool, check data list item AF: 
Heated Oxygen Sensor Bank 2, Sensor 2 (left rear).

CAUTION

To prevent damage to diagnostic tool, always turn the igni-
tion switch to the "LOCK" (OFF) position before connect-
ing or disconnecting diagnostic tool .
(1) Connect diagnostic tool  to the data link connector.
(2) Start the engine and run at idle.
(3) Set diagnostic tool  to the data reading mode for item AF, 

Heated Oxygen Sensor Bank 2, Sensor 2 (left rear).

• Warming up the engine. When the engine is revved, the 

output voltage should repeat 0 volt and 0.6 to 1.0 volt 
alternately.

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

Q: Is the sensor operating properly?

YES : Go to Step 3.
NO :  Refer to DTC P0156 

− Heated Oxygen Sensor Circuit 

(Bank 2, Sensor 2) 

P.13A-238

, DTC P0157 

− Heated 

Oxygen Sensor Circuit Low Voltage (Bank 2, Sensor 
2) 

P.13A-244

, DTC P0158 

− Heated Oxygen Sensor 

Circuit High Voltage (Bank 2, Sensor 2) 

P.13A-250

, 

DTC P0159 

− Heated Oxygen Sensor Circuit Slow 

Response (Bank 2, Sensor 2) 

P.13A-255

.

STEP 3. Test the EOBD drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− EOBD Drive Cycle − 

P.13A-11

.

(2) Read the diagnostic trouble code.

Q: Is DTC P0431 set?

YES : Replace the left bank side catalytic converter.
NO :  The inspection is complete.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-387

DTC P0441: Evaporative Emission Control System Incorrect Purge Flow.

.

CIRCUIT OPERATION

• The evaporative emission purge solenoid power 

is supplied from the MPI relay (terminal No. 4).

• The ECU controls ground evaporative emission 

purge solenoid by turning the power transistor in 
the ECU "ON" and "OFF".

.

TECHNICAL DESCRIPTION

• To judge if the purge valve is stuck open.

.

DTC SET CONDITIONS

Check Conditions

• Battery voltage is between 9.04 and 16.01volts.

Engine speed is above 801r/min.

Judgment Criteria

• Purge valve operation 

• No MIL.

.

EOBD DRIVE CYCLE PATTERN

Refer to Diagnostic Function 

− EOBD Drive Cycle − 

P.13A-11

.

.

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

• Purge solenoid valve stuck open.

• Refer to component locations GROUP-

70

• Refer to configuration diagrams GROUP-

80

• Refer to circuit diagrams GROUP-

90

DIAGNOSIS

Required Special Tools:

• Diagnostic tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

03DB193A

F-08

EVAPORATIVE

EMISSION PURGE

SOLENOID

1

2

HARNESS

CONNECTOR:

COMPONENT SIDE