Mitsubishi Lancer (4A9 engine). Manual - part 235

 

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Mitsubishi Lancer (4A9 engine). Manual - part 235

 

 

SECURITY ALARM

CHASSIS ELECTRICAL

54A-602

Inspection Procedure 4: Horns do not sound while the security alarm system is triggered.

CAUTION

Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communica-
tion circuit are normal.

Horn Circuit

ETACS-ECU

RELAYBOX

HORN 
RELAY

HORN 
(HI)

HORN 
(LO)

ENGINE 
COMPARTMENT

Wire colour code 
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue 
BR : Brown     O : Orange     GR : Grey     R : Red     P : Pink     V : Violet     PU : Purple     SI : Silver

FUSIBLE 
LINK

36

38

NOTE

:PETROL
:DIESEL

ACA01093

AC612144

AB

Connector: A-13X <Except RALLIART>

ACA01094AB

Connector: A-13X <RALLIART>

SECURITY ALARM

CHASSIS ELECTRICAL

54A-603

TECHNICAL DESCRIPTION (COMMENT)
If horns do not sound, the horn input signal circuit or 
the ETACS-ECU may be defective.

TROUBLESHOOTING HINTS

• Horns may be defective

• 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 PROCEDURE

STEP 1. M.U.T.-III diagnosis code. 
Check if diagnosis code is set to the ETACS-ECU.

Q: Is the diagnosis code set?

YES : 

Diagnose the ETACS-ECU. Refer to 

GROUP 54A, Diagnosis .

NO : 

Go to Step 2.

STEP 2. Connector check: A-13X horn relay 
connector

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the defective connector.

STEP 3. Horn relay check
Refer to .

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Replace the horn relay.

STEP 4. Voltage measurement at the A-13X horn 
relay
(1) Remove the relay, and measure at the relay box 

side.

(2) Measure the voltage between the A-13X horn 

relay connector terminal No. 2, 4 and the body 
earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Go to Step 5.

STEP 5. Wiring harness check between the A-13X 
horn relay connector terminal No. 2, 4 and the 
fusible link (36) <PETROL> or (38) <DIESEL>
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 

Cope with Intermittent Malfunction ).

NO : 

Repair the wiring harness.

STEP 6. Connector check: C-312 ETACS-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the defective connector.

STEP 7. Wiring harness check between the A-13X 
horn relay connector terminal No. 1 and the C-
312 ETACS-ECU connector terminal No. 11
Check the output lines for open circuit and short cir-
cuit.

Q: Is the check result normal?

YES : 

Go to Step 8.

NO : 

Repair the wiring harness.

ACA00916

AB

Connectors: A-42, A-48

A-48 (B)

A-42 (B)

ACA00886

AJ

Connector: C-312 <LHD>
ETACS-ECU

ACA00887

AJ

Connector: C-312 <RHD>
ETACS-ECU

SECURITY ALARM

CHASSIS ELECTRICAL

54A-604

STEP 8. Connector check: A-48 horn (HI) 
connector

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Repair the damaged parts.

STEP 9. Wiring harness check between the A-15X 
horn relay connector terminal No. 3 and the A-48 
horn (HI) connector terminal No. 1
Check the output lines for open circuit and short cir-
cuit.

Q: Is the check result normal?

YES : 

Go to Step 10.

NO : 

Repair the wiring harness.

STEP 10. Horn (HI) check

Connect the battery as shown, and verify that the 
horn sounds.

Q: Is the check result normal?

YES : 

Go to Step 11.

NO : 

Replace the horn (HI). go to step 11.

STEP 11. Connector check: A-42 horn (LO) 
connector

Q: Is the check result normal?

YES : 

Go to Step 12.

NO : 

Repair the damaged parts.

STEP 12. Wiring harness check between the A-
13X horn relay connector terminal No. 3 and the 
A-42 horn (LO) connector terminal No. 1
Check the output lines for open circuit and short cir-
cuit.

Q: Is the check result normal?

YES : 

Go to Step 13.

NO : 

Repair the wiring harness.

STEP 13. Check the horn (LO) work normally.

Connect the battery as shown, and verify that the 
horn sounds.

Q: Does the horn (LO) work normally?

YES : 

Go to Step 14.

NO : 

Replace the horn (LO).go to step 14.

STEP 14. Retest the security alarm system.

Q: Does the theft-alarm system work normally?

YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

Cope with Intermittent Malfunction ).

NO : 

Replace the ETACS-ECU.

AC607630

AC607630

SECURITY ALARM

CHASSIS ELECTRICAL

54A-605

Inspection Procedure 5: The activated security alarm siren sounds even though no faulty operation is 
made.

CAUTION

Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communica-
tion circuit are normal.

Security Alarm Siren Communication Circuit

ETACS-
ECU

LIN CUTOFF 
CONTROL 
UNIT

Wire colour code 
B : Black     LG : Light green     G : Green     L : Blue     W : White     Y : Yellow     SB : Sky blue 
BR : Brown     O : Orange     GR : Grey     R : Red     P : Pink     V : Violet     PU : Purple     SI : Silver

ACA00891

AB

Connector: C-63 <LHD>

ACA00896

AB

Connector: C-63 <RHD>

ACA00886

AK

Connectors: C-301, C-312 <LHD>
ETACS-ECU

C-301

C-312

ACA00887

AK

Connectors: C-301 C-312 <RHD>

ETACS-ECU

C-301

C-312

 

 

 

 

 

 

 

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