Mitsubishi Evolution X. Manual - part 1084

THEFT ALARM

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CHASSIS ELECTRICAL

54A-697

.

TECHNICAL DESCRIPTION (COMMENT)

If theft-horn does not sound, the theft-horn input sig-
nal circuit or the ETACS-ECU may be defective. 
Also, the theft-alarm function and horn may have 
been disabled with a configuration function.

.

TROUBLESHOOTING HINTS

• Theft-alarm horn may be defective

• Theft-alarm horn relay may be defective

• The ETACS-ECU may be defective

• The wiring harness or connectors may have 

loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector

DIAGNOSIS

Required Special Tools:

• MB992006: Extra fine probe

• 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)

AC708948AJ

Connector: A-59

A-59 (B)

AC708972AP

Connector: C-312

ETACS-ECU

THEFT ALARM

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STEP 1. Using scan tool MB991958, read the diagnostic 
trouble code. 
Check if DTC is set to the ETACS-ECU.

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-685

."

(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 

P.54A-582

.

NO :  Go to Step 2.

STEP 2. Check the theft-alarm horn work normally.
Connect the battery as shown, and verify that the theft-alarm 
horn sounds.
Q: Is the check result normal?

YES : Go to Step 3.
NO :  Replace the theft-alarm horn. go to Step 3.

STEP 3. Check theft-alarm horn connector A-59 for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Is theft-alarm horn connector A-59 in good condition?

YES : Go to Step 4.
NO :  Repair the damaged parts.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

AC607630AC

THEFT ALARM

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CHASSIS ELECTRICAL

54A-699

STEP 4. Check theft-alarm horn relay connector A-18X for 
loose, corroded or damaged terminals, or terminals 
pushed back in the connector.
Q: Is theft-alarm horn relay connector A-18X in good 

condition?
YES : Go to Step 5.
NO :  Repair the damaged parts.

STEP 5. Check the theft-alarm horn relay.
Refer to 

P.54A-706

.

Q: Is the theft-alarm horn relay in good condition

YES : Go to Step 6.
NO :  Replace the theft-alarm horn relay.

STEP 6. Measure the voltage at theft-alarm horn relay 
A-18X.
(1) Remove the relay, and measure at the relay box side.
(2) Measure the voltage between theft-alarm horn relay 

connector A-18X (terminal No. 1,4) and the body ground.

• The voltage should measure approximately 12 volts 

(battery positive voltage).

Q: Is the measured voltage approximately 12 volts (battery 

positive voltage)?
YES : Go to Step 8.
NO :  Go to Step 7.

STEP 7. Check the Wiring harness between theft-alarm 
horn relay connector A-18X (terminal No. 1,4) and fusible 
link (36).
Check the power supply line for open circuit and short circuit.
Q: Is the check result normal?

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 :  Repair the wiring harness between theft-alarm horn 

relay connector A-18X and fusible link (36).

STEP 8. Check theft-alarm horn connector A-59 for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Is theft-alarm horn connector A-59 in good condition?

YES : Go to Step 9.
NO :  Repair the damaged parts.

AC702831CO

Relay box side: A-18X

THEFT ALARM

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STEP 9. Check the Wiring harness between theft-alarm 
horn connector A-59 (terminal No. 1) and theft-alarm horn 
relay connector A-18X (terminal No. 3).
Check the output lines for open circuit and short circuit.
NOTE: Before the wiring harness check, check intermediate 
connector A-09, and then repair them if necessary.
Q: Is the check result normal?

YES : Go to Step 10.
NO :  Repair the wiring harness between theft-alarm horn 

connector A-59 and theft-alarm horn relay connector 
A-18X.

STEP 10. Check ETACS-ECU connector C-312 for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Is ETACS-ECU connector C-312 in good condition?

YES : Go to Step 11.
NO :  Repair the damaged parts.

STEP 11. Check the Wiring harness between theft-alarm 
horn relay connector A-18X (terminal No. 2) and 
ETACS-ECU connector C-312 (terminal No. 15).
Check the output lines for open circuit or short circuit.
Q: Is the check result normal?

YES : Go to Step 12.
NO :  Repair the wiring harness between theft-alarm horn 

relay connector A-18X and ETACS-ECU connector 
C-312.

STEP 12. Replace theft-alarm horn.
(1) Replace the theft-alarm horn.
Q: Does the theft-alarm work normally?

YES : he 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.