Mitsubishi Lancer Evolution X. Manual - part 396

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-649

TECHNICAL DESCRIPTION

• The accelerator pedal position sensor (sub) out-

puts voltage which corresponds to the accelera-
tor pedal depression.

• The ECM checks whether the voltage is within a 

specified range.

.

DESCRIPTIONS OF MONITOR METHODS

Accelerator pedal position sensor (sub) output volt-

age is out of specified range.

.

MONITOR EXECUTION

Continuous

.

MONITOR EXECUTION CONDITIONS 
(Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Not applicable

.

DTC SET CONDITIONS
Logic Flow Chart

.

Check Condition

• Ignition switch is "ON" position.

Judgement Criterion

• Accelerator pedal position sensor (sub) output 

voltage is 0.2 volt or less for 0.3 second.

.

FAIL-SAFE AND BACKUP FUNCTION

• Throttle opening degree is restricted.
• Throttle opening degree position is in default 

position if accelerator pedal position sensor 
(main) fails.

.

OBD-II DRIVE CYCLE PATTERN

None.

.

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

• Accelerator pedal position sensor failed.
• Open or shorted accelerator pedal position sen-

sor (sub) circuit, harness damage or connector 
damage.

• ECM failed. 

AK800588

Good

Malfunction

End

No

No

Output voltage <= 0.2V

Start

Yes

Yes

Continuous

failure for 0.3sec

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-650

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.
• MB991827: USB Cable
• MB991910: Main Harness A

STEP 1. Using scan tool MB991958, check data list item 12: 
Accelerator Pedal Position Sensor (sub).

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) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to the data reading mode for item 

12, Accelerator Pedal Position Sensor (sub).

• Output voltage is between 0.4 and 0.6 volt when foot is 

released from accelerator pedal.

• Output voltage is 2.0 volts or higher when accelerator 

pedal is fully depressed.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?

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.

STEP 2. Check harness connector C-01 at accelerator 
pedal position sensor for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 3.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 11.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-651

STEP 3. Measure the sensor supply voltage at accelerator 
pedal position sensor harness side connector C-01.
(1) Disconnect the connector C-01 and measure at the harness 

side.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal No. 4 and ground.

• Voltage should be between 4.9 and 5.1 volts.

(4) 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 7.
NO :   Go to Step 4.

STEP 4. Check harness connector B-10 at ECM for 
damage.
Q: Is the harness connector in good condition?

YES : Go to Step 5.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 11.

STEP 5. Check for open circuit and short circuit to ground 
between accelerator pedal position sensor connector C-01 
(terminal No. 4) and ECM connector B-10 (terminal No. 78).
Q: Is the harness wire in good condition?

YES : Go to Step 6.
NO :  Repair it. Then go to Step 11.

STEP 6. Using scan tool MB991958, check data list item 12: 
Accelerator Pedal Position Sensor (sub).
(1) Turn the ignition switch to the "ON" position.
(2) Set scan tool MB991958 to the data reading mode for item 

12, Accelerator Pedal Position Sensor (sub).

• Output voltage is between 0.4 and 0.6 volt when foot is 

released from accelerator pedal.

• Output voltage is 2.0 volts or higher when accelerator 

pedal is fully depressed.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?

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 :  Replace the ECM. When the ECM is replaced, 

register the ID code. Refer to GROUP 42B, ID Code 
Registration Necessity Judgment Table <Vehicles 
with KOS> 

P.42B-11

 or GROUP 42C, ID Codes 

Registration Judgment Table <Vehicles with WCM> 

P.42C-9

. Then go to Step 11.

AK704746

1

6 5 4 3 2

AB

C-01 harness
connector:
component side 

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-652

STEP 7. Check harness connector B-10 at ECM for 
damage.
Q: Is the harness connector in good condition?

YES : Go to Step 8.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 11.

STEP 8. Check for harness damage between accelerator 
pedal position sensor connector C-01 (terminal No. 4) and 
ECM connector B-10 (terminal No. 78).
Q: Is the harness wire in good condition?

YES : Go to Step 9.
NO :  Repair it. Then go to Step 11.

STEP 9. Check for open circuit, short circuit to ground and 
harness damage between accelerator pedal position 
sensor connector C-01 (terminal No. 6) and ECM connector 
B-10 (terminal No. 77)
Q: Is the harness wire in good condition?

YES : Go to Step 10.
NO :  Repair it. Then go to Step 11.

STEP 10. Replace the accelerator pedal position sensor.
(1) Replace the accelerator pedal position sensor.
(2) Turn the ignition switch to the "ON" position.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P2127 set?

YES : Replace the ECM. When the ECM is replaced, 

register the ID code. Refer to GROUP 42B, ID Code 
Registration Necessity Judgment Table <Vehicles 
with KOS> 

P.42B-11

 or GROUP 42C, ID Codes 

Registration Judgment Table <Vehicles with WCM> 

P.42C-9

. Then go to Step 11.

NO :  The inspection is complete.

STEP 11. Using scan tool MB991958, read the diagnostic 
trouble code (DTC).
(1) Turn the ignition switch to the "ON" position.
(2) After the DTC has been deleted, read the DTC again.
(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P2127 set?

YES : Retry the troubleshooting.
NO :  The inspection is complete.