Mitsubishi Evolution X. Manual — part 944

HEADLIGHT

TSB Revision

CHASSIS ELECTRICAL

54A-137

STEP 8. Check the wiring harness between headlight relay
(HIGH) connector A-21X (terminal 2 or 4) and the fusible
link (36).

• Check the power supply line for open circuit.

Q: Is the wiring harness between headlight relay (HIGH)

connector A-21X (terminal 2 or 4) and fusible link (36) in
good condition?
YES : Go to Step 9.
NO : The wiring harness may be damaged or the

connector(s) may have loose, corroded or damaged
terminals, or terminals pushed back in the connector.
Repair the wiring harness as necessary. Verify that
the high-beam headlights illuminate normally.

STEP 9. Retest the system
Q: Does the headlights (high-beam) do not illuminate in

good condition?
YES : The trouble can be an intermittent malfunction (Refer

to GROUP 00, How to use
Troubleshooting/inspection Service Points, How to
Cope with Intermittent Malfunction

P.00-15

).

NO : Replace the ETACS-ECU.

Inspection Procedure 3: The headlights illuminate at low-beam (high-beam does not illuminate)
regardless of the lighting switch positions.

CAUTION

Whenever the ECU is replaced, ensure that the power sup-
ply circuit, the ground circuit and the communication cir-
cuit are normal.

.

TECHNICAL DESCRIPTION (COMMENT)

If the headlights illuminate only at low-beam regardless of the
lighting switch position, the headlight fail-safe function may be
active.

.

TROUBLESHOOTING HINTS

• Malfunction of column switch

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

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 (Vehicles with

CAN communication system)

HEADLIGHT

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CHASSIS ELECTRICAL

54A-138

STEP 1. Using scan tool MB991958, read the diagnostic
trouble code.

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. Refer to "How to connect

scan tool (M.U.T.-III)

P.54A-105

."

(2) Turn the ignition switch to the "ON" position.
(3) Check whether the ETACS-ECU related DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

YES : Diagnose the ETACS-ECU. Refer to ETACS,

Diagnosis

P.54A-582

.

NO : Go to Step 2.

STEP 2. Retest the system
Q: Do the headlights illuminate normally?

YES : The trouble can be an intermittent malfunction (Refer

to GROUP 00, How to use
Troubleshooting/inspection Service Points, How to
Cope with Intermittent Malfunction

P.00-15

).

NO : Replace the ETACS-ECU.

Inspection Procedure 4: Headlights do not illuminate when the passing switch is operated.

CAUTION

Whenever the ECU is replaced, ensure that the power sup-
ply circuit, the ground circuit and the communication cir-
cuit are normal.

.

TECHNICAL DESCRIPTION (COMMENT)

If both headlights (low-beam and high-beam) do not illuminate,
the passing switch input circuit or ETACS-ECU may have a
problem.

.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

HEADLIGHT

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CHASSIS ELECTRICAL

54A-139

TROUBLESHOOTING HINTS

• Malfunction of column switch

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:

• MB991223: Harness set

• 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 (Vehicles with

CAN communication system)

STEP 1. Check that the headlights operate.
Check that the low-beam and high-beam headlights illuminate
normally.
Q: Is the check result normal?

YES : Go to Step 2.
NO : Refer to Inspection Procedure 1 "All the headlights

(low-beam) do not illuminate."

P.54A-128

and

Inspection Procedure 2 "All the headlights
(high-beam) do not illuminate."

P.54A-133

.

STEP 2. Using scan tool MB991958, read the ETACS-ECU
diagnostic trouble code.

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. Refer to "How to connect

scan tool (M.U.T.-III)

P.54A-105

."

(2) Turn the ignition switch to the "ON" position.
(3) Check whether the ETACS-ECU related DTC is set.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?

YES : Diagnose the ETACS-ECU. Refer to ETACS,

Diagnosis

P.54A-582

.

NO : Go to Step 3.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

HEADLIGHT

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CHASSIS ELECTRICAL

54A-140

STEP 3. Retest the system
Q: Do the headlights (low-beam and high-beam) illuminate

normally when turning ON the passing switch?
YES : The trouble can be an intermittent malfunction (Refer

to GROUP 00, How to use
Troubleshooting/inspection Service Points, How to
Cope with Intermittent Malfunction

P.00-15

).

NO : Replace the ETACS-ECU.

Inspection Procedure 5: One of the headlights does not illuminate.

Headlights Circuit <Halogen Type>

HEADLIGHT
ASSEMBLY
(RH)

HEADLIGHT
ASSEMBLY
(LH)

HEADLIGHT
RELAY (LOW)

HEADLIGHT
RELAY (HIGH)

RELAY
BOX