Mitsubishi Lancer (4A9 engine). Manual - part 232

SECURITY ALARM

CHASSIS ELECTRICAL

54A-590

SECURITY ALARM

SPECIAL TOOLS

M1547000600305

SECURITY ALARM

CHASSIS ELECTRICAL

54A-591

Tool

Number

Name

Use

MB990784

Ornament 
remover

Removal of centre air outlet, centre 
panel

MB990784

SECURITY ALARM

CHASSIS ELECTRICAL

54A-592

MB991955

a. MB991824
b. MB991827
c. MB991910
d. MB991911
e. MB991825
f. MB991826

M.U.T.-III sub-
assembly

a. Vehicle 

Communicatio
n Interface 
(V.C.I.)

b. M.U.T.-III USB 

cable

c. M.U.T.-III main 

harness A 
(Vehicles with 
CAN 
communication 
system)

d. M.U.T.-III main 

harness B 
(Vehicles 
without CAN 
communication 
system)

e. M.U.T.-III 

measure 
adapter

f. M.U.T.-III 

trigger harness

CAUTION

For vehicles with CAN 
communication, use M.U.T.-III 
main harness A to send simulated 
vehicle speed. If you connect 
M.U.T.-III main harness B instead, 
the CAN communication does not 
function correctly.
Diagnosis code, service data and 
actuator test check.

MB991223

a. MB991219
b. MB991220
c. MB991221
d. MB991222

Harness set

a. Check harness
b. LED harness
c. LED harness 

adapter

d. Probe

Continuity check and voltage 
measurement at harness wire or 
connector

a. For checking connector pin 

contact pressure

b. For checking power supply circuit
c. For checking power supply circuit
d. For connecting a locally sourced 

tester

Tool

Number

Name

Use

MB991910

MB991826

MB991955

MB991911

MB991824

MB991827

MB991825

a

b

c

d

e

f

DO NOT USE

MB991223

a

d

c

b

DO NOT USE

BA

SECURITY ALARM

CHASSIS ELECTRICAL

54A-593

TROUBLESHOOTING

STANDARD FLOW OF DIAGNOSTIC 
TROUBLESHOOTING

M1547001200076

Refer to GROUP 00 

− Contents of troubleshooting .

DIAGNOSIS FUNCTION

M1547001300073

HOW TO READ DIAGNOSIS CODE

Refer to GROUP 00 

− Diagnosis function .

HOW TO ERASE DIAGNOSIS CODE

Refer to GROUP 00 

− Diagnosis function .

DIAGNOSIS CODE CHART

M1547001400188

DIAGNOSIS CODE PROCEDURES

Code No.B120A Security alarm siren error

CAUTION

Before replacing the ECU or sensor, ensure that the power supply circuit, the earth circuit and the 
communication circuit are normal.
DIAGNOSTIC FUNCTION

• The security alarm siren communicates with the 

ETACS-ECU by the LIN via the LIN cutoff control 
unit. The diagnosis code No. B120A is set if the 
communication data between the EATCS-ECU 
and security alarm siren has an error when the 
relay inside the LIN cutoff control unit is ON 

(alarm is not activated.)

TROUBLESHOOTING HINT
Malfunction of security alarm siren

MB992006

Extra fine probe

Continuity check and voltage 
measurement at harness wire or 
connector

Tool

Number

Name

Use

MB992006

Diagnosis code No.

Diagnostic item

Reference page

B120A

Security alarm siren error

B120B

Security alarm sensor error

B120C

Security alarm siren Flat Battery

U1006

Security alarm siren LIN timeout

Refer to GROUP 54B - 
Diagnosis code chart 

U1007

Security alarm sensor LIN timeout

Refer to GROUP 54B - 
Diagnosis code chart 

U1539

Security alarm siren LIN checksum error

Refer to GROUP 54B - 
Diagnosis code chart 

U1540

Security alarm SNSR.LIN checksum error

Refer to GROUP 54B - 
Diagnosis code chart