Mitsubishi 380. Manual - part 334

ENGINE CONTROL

ENGINE AND EMISSION CONTROL

17-4

SYMPTOM CHART

M1171002200292

SYMPTOM PROCEDURES

INSPECTION PROCEDURE 1: Throttle Valve Will Not Fully Open or Close

.

COMMENT

The throttle body or accelerator pedal position (APP) 
sensor is suspected.

.

TROUBLESHOOTING HINTS (THE MOST 
LIKELY CAUSES FOR THIS CASE:)

• Malfunction of the throttle body.

• Malfunction of the accelerator pedal position 

(APP) sensor.

• Malfunction of the Engine ECU.

Circuit drawings

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

• Refer to component locations GROUP-

70

SYMPTOM

INSPECTION PROCEDURE

REFERENCE PAGE

Throttle Valve Will Not Fully Open or Close

1

P.17-4

Accelerator Pedal Operation Not Smooth (Over 
Acceleration)

2

P.17-6

ENGINE CONTROL

ENGINE AND EMISSION CONTROL

17-5

DIAGNOSIS

Required Special Tools:

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

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

STEP 1. Using Diagnostic Tool MB991958, read the 
diagnostic trouble code (DTC).

CAUTION

To prevent damage to Diagnostic Tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting Diagnostic Tool 
MB991958.
(1) Ensure that the ignition switch is at the "LOCK" (OFF) 

position.

(2) Start up the personal computer.
(3) Connect special tool MB991827 to special tool MB991824 

and the personal computer.

(4) Connect special tool MB991910 to special tool MB991824.
(5) Connect special tool MB991910 to the data link connector.
(6) Turn the power switch of special tool MB991824 to the "ON" 

position.

NOTE: When special tool MB991824 is energized, special 
tool MB991824 indicator lamp will be illuminated in a green 
color.

(7) Start the MUT-III system on the personal computer.
(8) Turn the ignition switch to the "ON" position.
(9) Check for MPI system diagnostic trouble code. (Refer to 

GROUP 13A, MPI Diagnosis 

− Diagnostic Function − How 

to Read and Erase Diagnostic Trouble Code 

P.13A-6

) .

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

then remove Diagnostic Tool MB991958 in the reverse 
order of installation.

Q: Is any DTC set?

YES : Repair MPI system.(Refer to GROUP 13A, MPI 

Diagnosis 

− Diagnostic Trouble Code Chart 

13A-17

) . 

Then go to Step 2.

NO :  Go to Step 2.

STEP 2. Retest the system.

Q: Does the throttle valve fully open and close?

YES : The procedure is complete.
NO :  Return to Step 1.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

ENGINE CONTROL

ENGINE AND EMISSION CONTROL

17-6

INSPECTION PROCEDURE 2: Accelerator Pedal Operation Not Smooth (Over Acceleration)

.

COMMENT

The accelerator pedal, its installation condition or the 
accelerator pedal position (APP) sensor is sus-
pected.

.

TROUBLESHOOTING HINTS (THE MOST 
LIKELY CAUSES FOR THIS CASE:)

• Malfunction of the accelerator pedal.

• Incorrectly installed accelerator pedal.

• Malfunction of the accelerator pedal position 

(APP) sensor.

Circuit drawings

• Refer to circuit diagrams GROUP-

90

• Refer to configuration diagrams GROUP-

80

• Refer to component locations GROUP-

70

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991910: MUT-III Main Harness A

STEP 1. Check if the accelerator pedal is installed 
correctly.

Q: Is the accelerator pedal installed correctly? 

YES : Go to Step 2.
NO :  Replace and reinstall the accelerator pedal. (Refer to 

P.17-9

). Go to Step 3.

ENGINE CONTROL

ENGINE AND EMISSION CONTROL

17-7

STEP 2. Using Diagnostic Tool MB991958, read the 
diagnostic trouble code (DTC).

CAUTION

To prevent damage to Diagnostic Tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting Diagnostic Tool 
MB991958.
(1) Ensure that the ignition switch is at the "LOCK" (OFF) 

position.

(2) Start up the personal computer.
(3) Connect special tool MB991827 to special tool MB991824 

and the personal computer.

(4) Connect special tool MB991910 to special tool MB991824.
(5) Connect special tool MB991910 to the data link connector.
(6) Turn the power switch of special tool MB991824 to the "ON" 

position.

NOTE: When special tool MB991824 is energized, special 
tool MB991824 indicator lamp will be illuminated in a green 
color.

(7) Start the MUT-III system on the personal computer.
(8) Turn the ignition switch to the "ON" position.
(9) Check for MPI system diagnostic trouble code.(Refer to 

GROUP 13A, MPI Diagnosis 

− Diagnostic Function − How 

to Read and Erase Diagnostic Trouble Code 

13A-6

) .

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

then remove Diagnostic Tool MB991958 in the reverse 
order of installation.

Q: Is any DTC set?

YES : Repair MPI system.(Refer to GROUP 13A, MPI 

Diagnosis 

− Diagnostic Trouble Code Chart 

13A-17

) . 

Then go to Step 3.

NO :  Go to Step 3.

STEP 3. Retest the system.

Q: Does the accelerator pedal work normally?

YES : The procedure is complete.
NO :  Return to Step 1.