Mitsubishi Lancer (4A9 engine). Manual - part 254

 

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Mitsubishi Lancer (4A9 engine). Manual - part 254

 

 

ACA00887

BF

Connector: C-301 <RHD>
ETACS-ECU

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-40

FUNCTION
If a short to earth is present in the CAN-C lines, this 
diagnosis result will be set.

TROUBLE JUDGEMENT CONDITIONS
If diagnosis code U1120 is set, the ETACS-ECU 
determines that there is a failure.

TROUBLESHOOTING HINTS

• Malfunction of the connector (short to earth inside 

connector)

• Malfunction of the wiring harness (short to earth 

in the CAN-C main or sub bus lines)

• Malfunction of the ECU (ETACS-ECU, or ECUs 

on CAN-C lines failed)

DIAGNOSIS PROCEDURE

STEP 1. Check the wiring harness between C-301 
ETACS-ECU connector and C-03 joint connector 
(CAN2) for short to earth (resistance 
measurement).

CAUTION

• Disconnect the negative battery terminal. For 

details refer to .

• A digital multimeter should be used. For 

details refer to .

• The test wiring harness should be used. For 

details refer to .

(1) Disconnect joint connector (CAN2), and measure 

at the wiring harness side.

(2) Resistance between C-03 joint connector (CAN2) 

terminal No.11 and body earth.

OK: 1 k

 or more

(3) Resistance between C-03 joint connector (CAN2) 

terminal No.22 and body earth.

OK: 1 k

 or more

Q: Is the check result normal?

YES <vehicles with ASC or AFS> : 

Go to Step 2.

YES <vehicles without ASC and without AFS with 
reversing sensor system> : 

Go to Step 3.

YES <vehicles without ASC and without AFS 
without reversing sensor system> : 

Go to Step 4.

NO  : 

Go to Step 12.

STEP 2. Check the wiring harness between C-211 
steering wheel sensor connector and C-03 joint 
connector (CAN2) for short to earth (resistance 
measurement).

CAUTION

• Disconnect the negative battery terminal. For 

details refer to .

• A digital multimeter should be used. For 

details refer to .

• The test wiring harness should be used. For 

details refer to .

(1) Disconnect joint connector (CAN2), and measure 

at the wiring harness side.

(2) Resistance between C-03 joint connector (CAN2) 

terminal No.9 and body earth.

OK: 1 k

 or more

(3) Resistance between C-03 joint connector (CAN2) 

terminal No.20 and body earth.

OK: 1 k

 or more

Q: Is the check result normal?

YES <vehicles with reversing sensor system> : 

Go 

to Step 3.

YES <vehicles without reversing sensor system> : 

Go to Step 4.

NO  : 

Go to Step 10.

STEP 3. Check the wiring harness between C-40 
corner sensor/back sensor-ECU connector and 
C-03 joint connector (CAN2) for short to earth 
(resistance measurement).

CAUTION

• Disconnect the negative battery terminal. For 

details refer to .

• A digital multimeter should be used. For 

details refer to .

• The test wiring harness should be used. For 

details refer to .

(1) Disconnect joint connector (CAN2), and measure 

at the wiring harness side.

(2) Resistance between C-03 joint connector (CAN2) 

terminal No.7 and body earth.

OK: 1 k

 or more

(3) Resistance between C-03 joint connector (CAN2) 

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-41

terminal No.18 and body earth.

OK: 1 k

 or more

Q: Is the check result normal?

YES <vehicles with AFS> : 

Go to Step 4.

YES <vehicles without AFS> : 

Go to Step 5.

NO  : 

Go to Step 11.

STEP 4. Check the wiring harness between C-14 
headlamp automatic levelling-ECU connector 
and C-124 joint connector (CAN3) for short to 
earth (resistance measurement).

CAUTION

• Disconnect the negative battery terminal. For 

details refer to .

• A digital multimeter should be used. For 

details refer to .

• The test wiring harness should be used. For 

details refer to .

(1) Disconnect joint connector (CAN3), and measure 

at the wiring harness side.

(2) Resistance between C-124 joint connector 

(CAN3) terminal No.7 <Petrol> or 8 <Diesel> and 
body earth

OK: 1 k

 or more

(3) Resistance between C-124 joint connector 

(CAN3) terminal No.18 <Petrol> or 19 <Diesel> 
and body earth

OK: 1 k

 or more

Q: Is the check result normal?

YES : 

Go to Step 5.

NO : 

Go to Step 13.

STEP 5. Check the wiring harness between A-04 
ABS-ECU connector <vehicles without ASC> or 
A-58 ASC-ECU connector <vehicles with ASC> 
and C-124 joint connector (CAN3) for short to 
earth (resistance measurement).

CAUTION

• Disconnect the negative battery terminal. For 

details refer to .

• A digital multimeter should be used. For 

details refer to .

• The test wiring harness should be used. For 

details refer to .

(1) Disconnect joint connector (CAN3), and measure 

at the wiring harness side.

(2) Resistance between C-124 joint connector 

(CAN3) terminal No.9 and body earth

OK: 1 k

 or more

(3) Resistance between C-124 joint connector 

(CAN3) terminal No.20 and body earth

OK: 1 k

 or more

Q: Is the check result normal?

YES <A/T or CVT> : 

Go to Step 6.

YES <M/T (vehicles with electric power steering) > : 

Go to Step 7.

YES <M/T (vehicles without electric power steering 
and with automatic stop & go (AS&G) system)> : 

Go to Step 8.

YES <M/T (vehicles without electric power steering 
and without automatic stop & go (AS&G) system)> 

Go to Step 9.

NO  : 

Go to Step 14.

STEP 6. Check the wiring harness between C-32 
A/T-ECU connector <A/T> or C-35 CVT-ECU 
connector <CVT> and C-124 joint connector 
(CAN3) for short to earth (resistance 
measurement).

CAUTION

• Disconnect the negative battery terminal. For 

details refer to .

• A digital multimeter should be used. For 

details refer to .

• The test wiring harness should be used. For 

details refer to .

(1) Disconnect joint connector (CAN3), and measure 

at the wiring harness side.

(2) Resistance between C-124 joint connector 

(CAN3) terminal No.8 and body earth

OK: 1 k

 or more

(3) Resistance between C-124 joint connector 

(CAN3) terminal No.19 and body earth

OK: 1 k

 or more

Q: Is the check result normal?

YES <vehicles with electric power steering> : 

Go 

to Step 7.

YES <vehicles without electric power steering and 
with automatic stop & go (AS&G) system> : 

Go to 

Step 8.

YES <vehicles without electric power steering and 
without automatic stop & go (AS&G) system> : 

Go 

to Step 9.

NO  : 

Go to Step 15.

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-42

STEP 7. Check the wiring harness between C-114 
electric power steering-ECU connector and C-
124 joint connector (CAN3) for short to earth 
(resistance measurement).

CAUTION

• Disconnect the negative battery terminal. For 

details refer to .

• A digital multimeter should be used. For 

details refer to .

• The test wiring harness should be used. For 

details refer to .

(1) Disconnect joint connector (CAN3), and measure 

at the wiring harness side.

(2) Resistance between C-124 joint connector 

(CAN3) terminal No.6 <Petrol> or 7 <Diesel> and 
body earth

OK: 1 k

 or more

(3) Resistance between C-124 joint connector 

(CAN3) terminal No.17 <Petrol> or 18 <Diesel> 
and body earth

OK: 1 k

 or more

Q: Is the check result normal?

YES <vehicles with automatic stop & go (AS&G) 
system> : 

Go to Step 8.

YES <vehicles without automatic stop & go (AS&G) 
system> : 

Go to Step 9.

NO  : 

Go to Step 16.

STEP 8. Check the wiring harness between C-64 
AS&G-ECU connector and C-124 joint connector 
(CAN3) for short to earth (resistance 
measurement).

CAUTION

• Disconnect the negative battery terminal. For 

details refer to .

• A digital multimeter should be used. For 

details refer to .

• The test wiring harness should be used. For 

details refer to .

(1) Disconnect joint connector (CAN3), and measure 

at the wiring harness side.

(2) Resistance between C-124 joint connector 

(CAN3) terminal No.16 <Petrol> or 17 <Diesel> 
and body earth

OK: 1 k

 or more

(3) Resistance between C-124 joint connector 

(CAN3) terminal No.5 <Petrol> or 6 <Diesel> and 
body earth

OK: 1 k

 or more

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Go to Step 17.

STEP 9. Check the wiring harness between B-09 
<Petrol> or B-40 <Diesel> engine-ECU connector 
and C-124 joint connector (CAN3) for short to 
earth (resistance measurement).

CAUTION

• Disconnect the negative battery terminal. For 

details refer to .

• A digital multimeter should be used. For 

details refer to .

• The test wiring harness should be used. For 

details refer to .

(1) Disconnect joint connector (CAN3), and measure 

at the wiring harness side.

(2) Resistance between C-124 joint connector 

(CAN3) terminal No.10 and body earth

OK: 1 k

 or more

(3) Resistance between C-124 joint connector 

(CAN3) terminal No.21 and body earth

OK: 1 k

 or more

Q: Is the check result normal?

YES : 

Check C-127 intermediate connector, and 

repair if necessary. If the intermediate 
connector is in good condition, repair the 
wiring harness between C-03 joint 
connector (CAN2) and C-124 joint 
connector (CAN3).

NO : 

Go to Step 18.

TROUBLESHOOTING

CONTROLLER AREA NETWORK (CAN)

54C-43

STEP 10. M.U.T.-III CAN bus diagnostics 
(checking the steering wheel sensor for internal 
short to earth)

CAUTION

Strictly observe the specified wiring harness 
repair procedure. For details refer to .
Disconnect C-211 steering wheel sensor connector, 
and diagnose the CAN bus line.

ACB01921AB

M.U.T.

JC

JC

SAS

KOS/
WCM

SRS

A/C

AUDIO

METER

AT/

CVT

EPS

ENGINE

ETACS

ABS/

ASC

MMCS

: Red section on screen

AS&G

Levelling

Cor ner

JC

OK: The display of the M.U.T.-III is as shown 
in the figure.

Q: Does M.U.T.-III screen correspond to the 

illustration?
YES : 

Repair the wiring harness between C-211 

steering wheel sensor connector and C-03 
joint connector (CAN2).

NO : 

Check the steering wheel sensor connector, 
and repair if necessary. If the steering wheel 
sensor connector is in good condition, 
replace the steering wheel sensor.

STEP 11. M.U.T.-III CAN bus diagnostics 
(checking the corner sensor/back sensor-ECU 
for internal short to earth)

CAUTION

Strictly observe the specified wiring harness 
repair procedure. For details refer to .
Disconnect C-40 corner sensor/back sensor-ECU 
connector, and diagnose the CAN bus line.

ACB01921AB

M.U.T.

JC

JC

SAS

KOS/
WCM

SRS

A/C

AUDIO

METER

AT/

CVT

EPS

ENGINE

ETACS

ABS/

ASC

MMCS

: Red section on screen

AS&G

Levelling

Cor ner

JC

OK: The display of the M.U.T.-III is as shown 
in the figure.

Q: Does M.U.T.-III screen correspond to the 

illustration?
YES : 

Repair the wiring harness between C-125 

corner sensor/back sensor-ECU connector 
and C-03 joint connector (CAN2).

NO : 

Check the corner sensor/back sensor-ECU 
connector, and repair if necessary. If the 
corner sensor/back sensor-ECU connector 
is in good condition, replace the corner 
sensor/back sensor-ECU.

STEP 12. Check the wiring harness between C-
301 ETACS-ECU connector and C-03 joint 
connector (CAN2) for short to earth (resistance 
measurement).

CAUTION

• Disconnect the negative battery terminal. For 

details refer to .

• A digital multimeter should be used. For 

details refer to .

• The test wiring harness should be used. For 

details refer to .

• Strictly observe the specified wiring harness 

repair procedure. For details refer to .

(1) Disconnect ETACS-ECU connector and joint 

connector (CAN2), and measure at the wiring 
harness side.

(2) Measure the resistance between C-03 joint 

connector (CAN2) terminal No.11 and body earth. 

 

 

 

 

 

 

 

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