Mitsubishi Evolution X. Manual - part 571

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-191

.

TROUBLESHOOTING HINTS

• Configration function setting

• Damaged wiring harness and connectors

• Malfunctions of the steering lock push switch

• Malfunction of the keyless operation key

• Malfunction of the receiver antenna assembly

• Malfunction of KOS-ECU

DIAGNOSIS

Required Special Tools:

• MB992006: Extra fine probe

• MB991223: Harness set

• MB991958 Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: Vehicles Communication Interface (V.C.I.)

• MB991827 M.U.T.-III USB Cable

• MB991910 M.U.T.-III Main Harness A

STEP 1. Check the power supply circuit and the ground 
circuit to KOS-ECU.
Refer to Inspection procedure 3 "Abnormality in KOS-ECU 
power supply and ground circuits" 

P.42B-185

.  

Q: Is the power supply circuit and the ground circuit to 

KOS-ECU in good condition?
YES : Go to Step 2.
NO :  Repair the power supply circuit and the ground circuit 

to KOS-ECU.

AC708950AX

C-41

Connectors: C-05, C-41

C-05

AC708951AW

Connector: C-16

C-16 (B)

AC708972AU

Connector: C-315

ETACS-ECU

AC708955AM

Connector: D-14

DIAGNOSIS

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KEYLESS OPERATION SYSTEM (KOS)

42B-192

STEP 2. Using scan tool MB991958, diagnose the CAN bus 
line.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958. Refer to "How to connect the 

Scan Tool (M.U.T.-III) 

P.42B-10

."

(2) Turn the ignition switch to the "ON" position.
(3) Diagnose the CAN bus line.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?

YES : Go to Step 3.
NO :  Repair the CAN bus line. (Refer to GROUP 54C, 

Diagnosis 

P.54C-14

).

STEP 3. Using scan tool MB991958, read the KOS-ECU 
diagnostic trouble code.
Check if DTC is set to the KOS-ECU.
Q: Is the DTC set?

YES : Troubleshoot the KOS. (Refer to 

P.42B-20

).

NO :  Go to Step 4.

STEP 4. Using scan tool MB991958, Check the 
configuration function.
Use the ETACS-ECU configuration function to check that the 
"KOS feature" is set to "Both enable" or "ENG strt enable".
Q: Is it set to "Both enable" or "ENG strt enable"?

YES : Go to Step 5.
NO :  Use the ETACS-ECU configuration function to set the 

"KOS feature" to "Both enable" or "ENG strt enable". 
(Refer to 

P.42B-276

).

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

DIAGNOSIS

TSB Revision

KEYLESS OPERATION SYSTEM (KOS)

42B-193

STEP 5. Check the ignition push switch.   Measure the 
resistance at KOS-ECU connector C-05.
(1) Disconnect the KOS-ECU connector C-05.
(2) With the IG knob push switch pressed, measure the 

resistance at the harness-side connector.

(3) Resistance between the KOS-ECU connector C-05 terminal 

No.8 and 34.

OK: The resistance should be 2 

Ω or less.

Q: Is the measured resistance 2 

Ω or less?

YES : Go to Step 6.
NO :  Check the KOS-ECU C-05 connector, the key 

reminder switch connector C-211, the ETACS-ECU 
connector C-315, and the wiring harness between the 
KOS-ECU connector C-05 (terminal No.8, 34) and the 
C-211 key reminder switch connector (terminal No.4, 
10), and between the key reminder switch connector 
C-211 (terminal No.1) and the ETACS-ECU connector 
C-315 (terminal No.10), and repair them if necessary. 
If they are normal, replace the key reminder switch.

STEP 6. Check the key reminder switch.  Measure the 
resistance at ETACS-ECU connector C-315.
(1) Disconnect the ETACS-ECU connector C-315.
(2) Measure the resistance at the harness-side connector with 

the ignition key removed from the ignition key cylinder.

(3) Resistance between the ETACS-ECU connector  C-315 

terminal No.13 and  the ground.

OK: The resistance should be 2 

Ω or less.

Q: Is the measured resistance 2 

Ω or less?

YES : Go to Step 7.
NO :  Check the key reminder switch connector C-211, the 

ETACS-ECU connector C-315, the wiring harness 
between the key reminder switch connector C-211 
(terminal No. 3) and the ETACS-ECU connector 
C-315 (terminal No. 13), and between the key 
reminder switch connector C-211 (terminal No. 2) and 
the ground.  If they are normal, replace the key 
reminder switch.

STEP 7. Check with another registered keyless operation 
key.
Q: Does the IG knob turn? (Is the keyless operation key 

recognised?)
YES : Replace the keyless operation key with which the IG 

knob does not turn (no recognition) and register the 
ID codes. (Refer to 

P.42B-12

.)

NO :  Go to Step 8.

AC709707EN

Harness side: C-05

AC608255 AQ

Harness side: C-315

DIAGNOSIS

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KEYLESS OPERATION SYSTEM (KOS)

42B-194

STEP 8. Check receiver antenna assembly connector D-14, 
KOS-ECU connector C-05, joint connector (6) C-16 and 
intermittent connector C-41 for loose, corroded or 
damaged terminals, or terminals pushed back in the 
connector.
Q: Is the receiver antenna assembly connector D-14, 

KOS-ECU connector C-05, joint connector (6) C-16 and 
intermittent connector C-41 in good condition?
YES : Go to Step 9.
NO :  Repair the defective connector.