Mitsubishi Lancer Evolution X. Manual - part 104

ENGINE CONTROL

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ENGINE AND EMISSION CONTROL

17-3

ENGINE CONTROL

GENERAL INFORMATION

M1171000101366

For the accelerator system, an electronic throttle 
valve control system is utilized, eliminating the accel-
erator cable.

CONSTRUCTION DIAGRAM

ENGINE CONTROL SYSTEM DIAGNOSIS

INTRODUCTION

M1171002000351

If there is a malfunction in the engine control system, 
the accelerator pedal or throttle body may be faulty.

TROUBLESHOOTING STRATEGY

M1171002100381

Use these steps to plan your diagnostic strategy.
If you follow them carefully, you will be sure that you 
have exhausted most of the possible ways to find an 
engine control system fault.
1. Gather information from the customer.

2. Verify that the condition described by the 

customer exists.

3. Find the malfunction by following the Symptom 

Chart.

4. Verify that the malfunction is eliminated.

SYMPTOM CHART

M1171002200429

AC613376AD

Accelerator pedal assembly
(Built-in accelerator pedal
position sensor)

Resin arm

Aluminum pedal pad

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.17-5

ENGINE CONTROL

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ENGINE AND EMISSION CONTROL

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SYMPTOM PROCEDURES

Inspection Procedure 1: Throttle Valve will not Fully Open or Close

.

COMMENT

The throttle body or accelerator pedal position sen-
sor is suspected.

.

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

• Malfunction of the throttle body.
• Malfunction of the accelerator pedal position sen-

sor.

• Malfunction of the engine control module (ECM).

DIAGNOSIS

Required Special Tools:

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

• MB991824: Vehicle Communication Interface (V.C.I.)
• MB991827: M.U.T.-III USB Cable
• MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, read the MFI system 
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) 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 light will be illuminated in a green 
color.

(7) Start the M.U.T.-III system on the personal computer.
(8) Turn the ignition switch to the "ON" position.
(9) Check for MFI system DTC. (Refer to GROUP 13A, MFI 

Diagnosis, Diagnostic Function − How to Read and Erase 

Diagnostic Trouble Codes 

P.13A-9

).

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

then remove scan tool MB991958 in the reverse order of 
installation.

Q: Is any DTC set?

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

Diagnosis − Diagnostic Trouble Code Chart 

P.13A-48

). Then go to Step 2.

NO :  Go to Step 2.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

ENGINE CONTROL

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ENGINE AND EMISSION CONTROL

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STEP 2. Retest the system.
Q: Does the throttle valve fully open and close?

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

Inspection Procedure 2: Accelerator Pedal Operation not Smooth (Over Acceleration)

.

COMMENT

The accelerator pedal, its installation condition or the 
accelerator pedal position sensor is suspected.

.

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

• Malfunction of the accelerator pedal.
• Incorrectly installed accelerator pedal.
• Malfunction of the accelerator pedal position sen-

sor.

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

STEP 1. Check if the accelerator pedal is installed 
correctly.
Q: Is the accelerator pedal installed correctly? 

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

P.17-8

). Then go to Step 3.

ENGINE CONTROL

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ENGINE AND EMISSION CONTROL

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STEP 2. Using scan tool MB991958, read the MFI system 
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) 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 light will be illuminated in a green 
color.

(7) Start the M.U.T.-III system on the personal computer.
(8) Turn the ignition switch to the "ON" position.
(9) Check for MFI system DTC. (Refer to GROUP 13A, MFI 

Diagnosis, Diagnostic Function − How to Read and Erase 

Diagnostic Trouble Codes 

P.13A-9

).

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

then remove scan tool MB991958 in the reverse order of 
installation.

Q: Is any DTC set?

YES : Repair MFI system (Refer to GROUP 13A, MFI 

Diagnosis − Diagnostic Trouble Code Chart 

P.13A-48

). 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.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB