Mitsubishi Lancer (4A9 engine). Manual - part 90

IGNITION SWITCH

CHASSIS ELECTRICAL

54A-22

OPERATION
The ETACS-ECU operates this function in accord-
ance with the input signals below.

• Ignition switch (IG1)

• Key reminder switch

• Driver's door switch

• Driver's door lock actuator

COMMENTS ON TROUBLE SYMPTOM
If this function does not work normally, these input 
signal circuit(s), the ignition key cylinder illumination 
lamp or the ETACS-ECU may be defective.

PROBABLE CAUSES

• Malfunction of the key reminder switch

• Malfunction of the driver's door switch

• Malfunction of the driver's door lock actuator

• Malfunction of the ignition key cylinder illumina-

tion lamp bulb

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

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 : 

Troubleshoot the ETACS-ECU. Refer to .

NO : 

Go to Step 2.

STEP 2. M.U.T.-III data list
Check the signal related to the operation of ignition 
key cylinder illumination lamp.

• Turn the ignition switch to the LOCK (OFF) posi-

tion.

• Remove the ignition key from the ignition key cyl-

inder.

• Open the driver's door.

OK: Normal conditions are displayed for all 
the items.

Q: Is the check result normal?

Normal conditions are displayed for all the items. : 

Go to Step 3.

Normal condition is not displayed for item No. 228. 
: 

Troubleshoot the ETACS-ECU. Refer to 
Inspection Procedure 4 "The front door lock 
actuator (driver’s side) signal is not 
received."  <LH drive vehicles>,  <RH drive 
vehicles>.

Normal condition is not displayed for item No. 254. 
: 

Troubleshoot the ETACS-ECU. Refer to 
Inspection Procedure 2 "The ignition switch 
(IG1) signal is not received." .

Normal condition is not displayed for item No. 256. 
: 

Troubleshoot the ETACS-ECU. Refer to 
Inspection Procedure 5 "The front door 
switch (driver’s side) signal is not received." 
.

Normal condition is not displayed for item No. 264. 
: 

Troubleshoot the ETACS-ECU. Refer to 
Inspection Procedure 3 "The key reminder 
switch signal is not received." .

Normal condition is not displayed for item No. 270, 
271. : 

Troubleshoot the ETACS-ECU. Refer to 
Inspection Procedure 4 "The front door lock 
actuator (driver’s side) signal is not 
received."  <LH drive vehicles>,  <RH drive 
vehicles>.

ACA00886

AN

Connector: C-315 <LHD>
ETACS-ECU

ACA00887

AL

Connector: C-315 <RHD>
ETACS-ECU

Item No.

Item name

Normal 
condition

Item 228

Dr door unlock

ON

Item 254

IG voltage

0 V

Item 256

Dr door ajar switch

OPEN

Item 264

Handle lock switch

Key in 

→ Key 

out

Item 270

Dr door lock switch

Not lock

Item 271

Dr door unlock 
switch

Unlock

IGNITION SWITCH

CHASSIS ELECTRICAL

54A-23

STEP 3. Connector check: C-213 key reminder 
switch connector, C-315 ETACS-ECU connector

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Repair the defective connector.

STEP 4. Wiring harness check between the C-213 
key reminder switch connector terminal No. 5 
and the C-315 ETACS-ECU connector terminal 
No. 18

• Check the input/output line for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Repair the wiring harness.

STEP 5. Check of ignition key cylinder 
illumination lamp bulb
Check that the ignition key cylinder illumination lamp 
bulb is normal.

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Replace the bulb of the ignition key cylinder 
illumination lamp.

STEP 6. Wiring harness check between the C-213 
key reminder switch connector terminal No. 7 
and the body earth

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the wiring harness.

STEP 7. Retest the system
Check that the ignition key cylinder illumination lamp 
illuminates/extinguishes normally.

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 : 

Replace the ETACS-ECU.

Inspection Procedure 2: Malfunction of the ignition switch power supply system

CAUTION

Whenever the ECU is replaced, ensure that the 
input and output signal circuits are normal.

Ignition Switch Power Source Circuit

ETACS-ECU

IGNITION 
SWITCH

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

IGNITION SWITCH

CHASSIS ELECTRICAL

54A-24

COMMENTS ON TROUBLE SYMPTOM
When the power supply system of ignition switch has 
a problem, none of the equipment and system con-
nected to the ignition switch works even if the ignition 
switch is operated.

POSSIBLE CAUSES

• Malfunction of the ignition switch

• Malfunction of the fuse No.14 

• Malfunction of the ETACS-ECU

• Damaged harness wires and connectors

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-204 ignition switch 
connector

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the defective connector.

STEP 2. Voltage measurement at ignition switch 
connector C-204 in order to check the battery 
circuit of power supply system to the ignition 
switch.
(1) Disconnect the ignition connector C-204 and 

measure the voltage at ignition switch connector 
C-204 harness side.

(2) Measure the voltage between terminal 1 and 

earth.

OK: System voltage

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Go to Step 3.

STEP 3. Check the fuse No.14.

Q: Is the check result normal?

YES : 

Go to Step 4.

NO : 

Replace the fuse No.14. (Check that there 
is not a short to earth in the circuit of lower 
reaches before replacing. If there are any 
problems, replace the fuse after the circuit 
of lower reaches is repaired.)

STEP 4. Connector check: C-316 ETACS-ECU 
connector

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Repair the defective connector.

STEP 5. Check the wiring harness from ignition 
switch connector C-204 (terminal No.1) and 
ETACS-ECU connector C-316 (terminal No.3).

• Check the battery power supply line for open cir-

cuit.

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Repair the wiring harness.

STEP 6. Check the ignition switch.
Refer to .

Q: Is the ignition switch in good condition?

AC612708

Connector: C-212 <LHD>

AG

AC612716

Connector: C-212 <RHD>

AG

ACA00886

AO

Connector: C-317 <LHD>
ETACS-ECU

ACA00887

AM

Connector: C-317 <RHD>
ETACS-ECU

IGNITION SWITCH

CHASSIS ELECTRICAL

54A-25

YES : 

Go to Step 7.

NO : 

Replace the ignition switch.

STEP 7. Retest the system.

Q: Do the device and the system work normally when 

the ignition switch is operated?
YES : 

The trouble can be an intermittent 

malfunction (Refer to GROUP 00 

− How to 

Cope with Intermittent Malfunction ).

NO : 

Replace the ETACS-ECU.

ON-VEHICLE SERVICE

Keyless operation key return reminder 
buzzer check <Vehicles with KOS>

M1541200700201

1. Release the steering wheel lock with the driver's 

door closed, and turn the IG knob to the position 
other than the LOCK (OFF) position.

2. Change the driver's door state from closed to 

open.

3. Check that the buzzer sounds normally.
4. If a malfunction is found, carry out the trouble-

shooting (Refer to ).