Mitsubishi Lancer (4A9 engine). Manual - part 240

TROUBLESHOOTING

LOCAL INTERCONNECT NETWORK (LIN)

54B-11

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-316 ETACS-ECU 
connector, D-02 lighting control sensor 
connector

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the defective connector.

STEP 2. Resistance measurement at the D-02 
lighting control sensor connector
(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Measure the resistance between the D-02 

lighting control sensor connector terminal No. 2 
and the body earth.

OK: Continuity exists (2 

Ω or less)

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Go to Step 3.

STEP 3. Wiring harness check from D-02 lighting 
control sensor connector terminal No. 2 to body 
earth
Check the earth wires for open 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 ).

NO : 

Repair the wiring harness.

STEP 4. Voltage measurement at the D-02 
lighting control sensor connector.
(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Measure the voltage between the D-02 lighting 

control sensor connector terminal No. 1 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 D-02 
lighting control sensor connector terminal No. 1 
and the C-317 ETACS-ECU connector terminal 
No. 10
Check the power supply line for open circuit and 
short circuit.
NOTE: Prior to the wiring harness inspection, check 
intermediate connector C-130, and repair if neces-
sary.

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 ).

NO : 

Repair the wiring harness.

STEP 6. Check the wiring harness wires between 
C-316 ETACS-ECU connector terminal No. 1 and 
D-02 lighting control sensor connector terminal 
No. 3.
Check the communication lines for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the wiring harness.

STEP 7. Check whether the diagnosis code is 
reset.
Check again if the diagnosis code is set to the 
ETACS-ECU.
(1) Erase the diagnosis code.
(2) Turn the ignition switch from the LOCK (OFF) 

position to the ON position.

(3) Check if diagnosis code is set.

Q: Is the diagnosis code set?

YES : 

Replace the lighting control sensor.

NO : 

A poor connection, open circuit, or other 
intermittent malfunctions in the LIN bus lines 
between the lighting control sensor and the 
ETACS-ECU (Refer to GROUP 00 

− How to 

Cope with Intermittent Malfunction ).

TROUBLESHOOTING

LOCAL INTERCONNECT NETWORK (LIN)

54B-12

Code No.U1006 Security alarm siren LIN timeout <Vehicles with security alarm sensor>

CAUTION

Before replacing the ECU, ensure that the communication circuit is normal.

INTERFACE 
CIRCUIT

LIN DRIVE 
CIRCUIT

SECURITY 
ALARM 
SIREN

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

Security Alarm Siren LIN Communication Circuit

ETACS-
ECU

FUSE     

8

ACA00897

AB

A-78 (B)

Connector: A-78

ACA00891

AB

Connector: C-63 <LHD>

ACA00896

AB

Connector: C-63 <RHD>

ACA00886

AD

Connectors: C-301, C-304, C-312, C-317 
<LHD>

ETACS-ECU

C-317

C-301

C-312

C-304

ACA00887

AD

Connectors: C-301, C-304, C-312, C-317 
<RHD>

ETACS-ECU

C-317

C-301

C-312

C-304

TROUBLESHOOTING

LOCAL INTERCONNECT NETWORK (LIN)

54B-13

JUDGEMENT CRITERIA
The ETACS-ECU will set diagnosis code No. U1006 
when no signals are received from the security alarm 
siren.

PROBABLE CAUSES

• Faulty security alarm siren

• Faulty LIN cutoff control unit

• Malfunction of the LIN bus

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-301, C-304, C-312 
and C-317 ETACS-ECU connectors, C-63 LIN 
cutoff control unit connector, A-78 security alarm 
siren connector

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the defective connector.

STEP 2. Resistance measurement at the A-78 
security alarm siren connector
(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Measure the resistance between the A-78 

security alarm siren connector terminal No. 1 and 
the body earth.

OK: Continuity exists (2 

Ω or less)

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Go to Step 3.

STEP 3. Wiring harness check from A-78 security 
alarm siren connector terminal No. 1 to body 
earth
Check the earth wires for open circuit.
NOTE: Prior to the wiring harness inspection, check 
intermediate connector A-79, and repair if necessary.

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 ).

NO : 

Repair the wiring harness.

STEP 4. Voltage measurement at the A-78 
security alarm siren connector.
(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Measure the voltage between the A-78 security 

TROUBLESHOOTING

LOCAL INTERCONNECT NETWORK (LIN)

54B-14

alarm siren connector terminal No. 2 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-78 
security alarm siren connector terminal No. 2 and 
the C-304 ETACS-ECU connector terminal No. 4
Check the power supply line for open circuit and 
short circuit.
NOTE: Prior to the wiring harness inspection, check 
intermediate connector A-79, and repair if necessary.

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 ).

NO : 

Repair the wiring harness.

STEP 6. LIN cutoff control unit check
Check the LIN cutoff control unit. Refer to GROUP 
54A 

− Security Alarm System .

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Replace the LIN cutoff control unit.

STEP 7. Voltage measurement at the C-312 
ETACS-ECU connector.
(1) Disconnect the connector, and measure at the 

wiring harness side.

(2) Measure the voltage between the C-312 ETACS-

ECU connector terminal No. 9 and the body 
earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 10.

NO : 

Go to Step 8.

STEP 8. Wiring harness check between the C-317 
ETACS-ECU connector terminal No. 10 and the C-
63 LIN cutoff control unit connector terminal No. 
1
Check the power supply line for open circuit and 
short circuit.

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Repair the wiring harness.

STEP 9. Wiring harness check between the C-63 
LIN cutoff control unit connector terminal No. 8 
and the C-312 ETACS-ECU connector terminal 
No. 9
Check the power supply line for open circuit and 
short circuit.
NOTE: Prior to the wiring harness inspection, check 
intermediate connector C-127, and repair if neces-
sary.

Q: Is the check result normal?

YES : 

Go to Step 12.

NO : 

Repair the wiring harness.

STEP 10. Check the wiring harness wires 
between C-301 ETACS-ECU connector terminal 
No. 1 and C-63 LIN cutoff control unit connector 
terminal No. 7.
Check the communication lines for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 11.

NO : 

Repair the wiring harness.

STEP 11. Check the wiring harness wires 
between C-63 LIN cutoff control unit connector 
terminal No. 5 and A-78 security alarm siren 
connector terminal No. 3.
NOTE: Prior to the wiring harness inspection, check 
intermediate connectors A-79 and C-127, and repair 
if necessary.
Check the communication lines for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 12.

NO : 

Repair the wiring harness.

STEP 12. Replace the security alarm siren 
temporarily, and check whether the diagnosis 
code is set.
Check again if the diagnosis code is set to the 
ETACS-ECU.
(1) Erase the diagnosis code.
(2) Turn the ignition switch from the LOCK (OFF) 

position to the ON position.

(3) Check if diagnosis code is set.

Q: Is the diagnosis code set?

YES : 

Replace the ETACS-ECU.

NO : 

Replace the security alarm siren.