Mitsubishi Lancer Evolution X. Manual — part 366

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-529

.

Check Conditions

• Engine coolant temperature is higher than 65° C

(149° F).

• Drive for 4 seconds or more with the vehicle

speed is 50 km/h (31 mph) or more. Stop the
vehicle [vehicle speed is 1.5 km/h (1.0 mph) or
less]. Repeat 10 times or more.

Judgement Criterion

• Power steering pressure switch continues to be

"ON".

.

FAIL-SAFE AND BACKUP FUNCTION

• None

.

OBD-II DRIVE CYCLE PATTERN

None.

.

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

• Power steering pressure switch failed.
• Open or shorted power steering pressure switch

circuit, harness damage, or connector damage.

• ECM failed.

DIAGNOSIS

Required Special Tools:

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

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

• MB992110: Power Plant ECU Check Harness

STEP 1. Using scan tool MB991958, check data list item 83:
Power Steering Pressure Switch.

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) Start the engine and run at idle.
(3) Set scan tool MB991958 to the data reading mode for item

83, Power Steering Pressure Switch.

• If the steering wheel is not turned while idling, "OFF" will

be displayed.

• If the steering wheel is turned while idling, "ON" will be

displayed.

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

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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STEP 2. Measure the power supply voltage at power
steering pressure switch connector B-19 by backprobing.
(1) Do not disconnect the connector B-19.
(2) Start the engine and run at idle.
(3) Measure the voltage between terminal No. 1 and ground by

backprobing.

• When steering wheel is not turned, voltage should be

battery positive voltage.

• When steering wheel is turned, voltage should be 1 volt

or less.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage within the specified range?

YES : Go to Step 3.
NO : Go to Step 5.

STEP 3. Check harness connector B-19 at power steering
pressure switch for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 4.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 13.

STEP 4. Using scan tool MB991958, check data list item 83:
Power Steering Pressure Switch.
(1) Start the engine and run at idle.
(2) Set scan tool MB991958 to the data reading mode for item

83, Power Steering Pressure Switch.

• If the steering wheel is not turned while idling, "OFF" will

be displayed.

• If the steering wheel is turned while idling, "ON" will be

displayed.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the switch 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 13.

STEP 5. Check harness connector B-19 at power steering
pressure switch for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 6.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 13.

AK704285

1

B-19 harness
connector:
harness side

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-531

STEP 6. Measure the power supply voltage at power
steering pressure switch harness side connector B-19.
(1) Disconnect the connector B-19 and measure at the harness

side.

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal No. 1 and ground.

• Voltage should be battery positive voltage.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts)

present?
YES : Go to Step 10.
NO : Go to Step 7.

STEP 7. Check harness connector B-09 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 13.

AK704286

1

B-19 harness
connector:
component side

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-532

STEP 8. Measure the power supply voltage at ECM
connector B-09 by using power plant ECU check harness
special tool MB992110.
(1) Disconnect all ECM connectors. Connect the power plant

ECU check harness special tool MB992110 between the
separated connectors.

(2) Disconnect the power steering pressure switch connector

B-19.

(3) Turn the ignition switch to the "ON" position.

(4) Measure the voltage between terminal No. 58 and ground.

• Voltage should be between battery positive voltage.

(5) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts)

present?
YES : Repair harness wire between power steering

pressure switch connector B-19 (terminal No. 1) and
ECM connector B-09 (terminal No. 58) because of
open circuit. Then go to Step 13.

NO : Go to Step 9.

STEP 9. Check for short circuit to ground between power
steering pressure switch connector B-19 (terminal No. 1)
and ECM connector B-09 (terminal No. 58).
Q: Is the harness wire in good condition?

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 13.

NO : Repair it. Then go to Step 13.

AK604040

ECM

AB

Body side harness

MB992110

AK604213

16 15 14 13 12 11 10 9 8 7 6 5 4 3

2

1

32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17

48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33

64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49

AB

Power plant ECU
check harness connector