Mitsubishi Evolution X. Manual - part 1070

ETACS

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CHASSIS ELECTRICAL

54A-641

STEP 2. Check the ignition switch (ACC) line of the power 
supply circuit to the ETACS-ECU. Measure the voltage at 
ETACS-ECU connector C-317.
(1) Disconnect ETACS-ECU connector C-317 and measure the 

voltage available at the junction block side of the connector.

(2) Turn the ignition switch to the "ACC" position.
(3) Measure the voltage between terminal 7 and ground.

• The voltage should measure approximately 12 volts 

(battery positive voltage).

Q: Is the measured voltage approximately 12 volts (battery 

positive voltage)?
YES : Replace the ETACS-ECU. Check that the input signal 

of ignition switch (ACC) is normal.

NO :  Go to Step 3.

STEP 3. Check the wiring harness between ETACS-ECU 
connector C-317 (terminal 7) and the ignition switch (ACC).
Check the power supply line (ACC) for open circuit and short 
circuit.
Q: Is the wiring harness between ETACS-ECU connector 

C-317 (terminal 7) and ignition switch (ACC) in good 
condition?
YES : No action is necessary and testing is complete.
NO :  The wiring harness may be damaged or the 

connector(s) may have loose, corroded or damaged 
terminals, or terminals pushed back in the connector. 
Repair the wiring harness as necessary. Check that 
the input signal of ignition switch (ACC) is normal.

AC608254 BK

Harness side: C-317

ETACS

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CHASSIS ELECTRICAL

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Inspection Procedure 2: ETACS-ECU does not receive any signal from the ignition switch (IG1).

.

TECHNICAL DESCRIPTION (COMMENT)

If there is an error to the ignition switch (IG1) input 
signal, or the IG1 relay inside the ETACS-ECU does 
not operate, the ignition switch (IG1) signal is no 
longer output to the communication line.

.

TROUBLESHOOTING HINTS

• The ignition switch may be defective

• The ETACS-ECU may be defective

• The fuse 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:

• MB991223: Harness Set

• MB992006: Extra Fine Probe

STEP 1. Check ETACS-ECU connector C-317 for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Is ETACS-ECU connector C-317 in good condition?

YES : Go to Step 2.
NO :  Repair or replace the damaged component(s) (Refer 

to GROUP 00E, Harness Connector Inspection 

P.00E-2

). Check that the input signal of ignition switch 

(IG1) is normal.

Ignition Switch (IG1) Input Circuit

ETACS-ECU

IGNITION
SWITCH (IG1)

AC708972AB

Connector: C-317

Junction block

ETACS

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CHASSIS ELECTRICAL

54A-643

STEP 2. Check the ignition switch (IG1) line of the power 
supply circuit to the ETACS-ECU. Measure the voltage at 
ETACS-ECU connector C-317.
(1) Disconnect ETACS-ECU connector C-317 and measure the 

voltage available at the junction block side of the connector. 

(2) Turn the ignition switch to the "ON" position.
(3) Measure the voltage between terminal 6 and ground.

• The voltage should measure approximately 12 volts 

(battery positive voltage).

Q: Is the measured voltage approximately 12 volts (battery 

positive voltage)?
YES : Replace the ETACS-ECU. Check that the input signal 

of ignition switch (IG1) is normal.

NO :  Go to Step 3.

STEP 3. Check the wiring harness between ETACS-ECU 
connector C-317 (terminal 6) and the ignition switch (IG1).
Check the power supply line (IG1) for open circuit and short cir-
cuit.
Q: Is the wiring harness between ETACS-ECU connector 

C-317 (terminal 6) and ignition switch (IG1) in good 
condition?
YES : No action is necessary and testing is complete.
NO :  The wiring harness may be damaged or the 

connector(s) may have loose, corroded or damaged 
terminals, or terminals pushed back in the connector. 
Repair the wiring harness as necessary. Check that 
the input signal of ignition switch (IG1) is normal.

AC608254 BJ

Harness side: C-317

ETACS

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CHASSIS ELECTRICAL

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Inspection Procedure 3: ETACS-ECU does not receive any signal from the key reminder switch.

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COMMENTS ON TROUBLE SYMPTOM

The key reminder switch input signal is used for the 
operation judgment of the functions below. If the sig-
nal is abnormal, these functions will not work.

• Ignition key reminder function

• Central door locking

• Keyless entry system

• KOS

• Ignition key cylinder illumination light

• Interior light

.

TROUBLESHOOTING HINTS

• The key reminder switch 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:

• MB991223: Harness Set

• MB992006: Extra Fine Probe

Key Reminder Switch Input Circuit

ETACS-
ECU

KEY REMINDER
SWITCH

WHEN KEY IS
REMOVED: ON

AC708953AC

Connector: C-211

AC708972AU

Connector: C-315

ETACS-ECU