Mitsubishi Lancer (4A9 engine). Manual — part 145

REVERSING SENSOR SYSTEM

CHASSIS ELECTRICAL

54A-242

COMMENTS ON TROUBLE SYMPTOM
If obstacle is not detected even when the selector or
shift lever is shifted to "R" (reverse) position, the wir-
ing harness, connectors, inhibitor switch <CVT, A/T>,
back-up lamp switch <M/T>, or corner sensor/back
sensor-ECU may be defective. In addition, obstacle
is not detected when the ultrasonic noise is received.
NOTE: If ultrasonic noise is received with the sensor,
the corner sensor/bock sensor sounds the low toned
buzzer continuously and turns off the system. When
the ultrasonic noise is stopped, the sensor returns to
normal.

PROBABLE CAUSES

• Damaged harness wires and connectors

• Malfunction of the inhibitor switch <CVT, A/T> or

back-up lamp switch <M/T>

• Malfunction of corner sensor/back sensor-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnostics
Use the M.U.T.-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the CAN bus line (Refer to GROUP
54C

− Troubleshooting ).

STEP 2. M.U.T.-III other system diagnosis code
Check if the diagnosis code is set to the ETACS-
ECU.

Q: Is the check result normal?

YES :

Troubleshoot the ETACS-ECU. Refer to

ETACS-ECU

− Troubleshooting .

NO :

Go to Step 3.

STEP 3. Check the reversing sensor (corner
sensor/back sensor) for interference.

Q: Is there anything that interferes with the

communication (things that generate radio waves
such as magnets and an air-cleaning device that

has a power plug) near the reversing sensor
(corner sensor/back sensor)?
YES :

Move away or remove things that interfere

with the communication (things that
generate radio waves such as magnets and
a air-cleaning device that has a power plug)
near the reversing sensor (corner sensor/
back sensor).

NO :

Go to Step 4.

STEP 4. Connector check: C-304 ETACS-ECU
connector and B-109 inhibitor switch connector
<CVT, A/T> or B-110 back-up lamp switch
connector <M/T>.

Q: Is the check result normal?

YES :

Go to Step 5

NO :

Repair the defective connector.

STEP 5. Voltage measurement at C-304 ETACS-
ECU connector.
(1) Disconnect C-304 ETACS-ECU connector, and

measure at the wiring harness side.

(2) Turn the ignition switch to the "ON" position, and

move the selector lever <CVT, A/T> or the shift
lever <M/T> to the "R" position.

(3) Measure the voltage between terminal No. 2 and

earth.

OK: System voltage

Q: Is the check result normal?

YES :

Go to Step 11

NO :

Go to Step 6

STEP 6. Check the wiring harness between B-109
inhibitor switch connector terminal (No. 7 <1600>
or 9 <1800, 2000>) <CVT, A/T> or B-110 back-up
lamp switch connector terminal No. 1 <M/T> and
C-304 ETACS-ECU connector terminal No. 2.

• Check the communication line for open circuit or

short circuit.

NOTE: Before the wiring harness inspection, inspect
the intermediate connectors A-11 <PETROL> and A-
60 <DIESEL>, and repair if necessary.

Q: Is the check result normal?

YES :

Go to Step 7

NO :

Repair the wiring harness.

STEP 7. Voltage measurement at B-109 inhibitor
switch connector <CVT, A/T> or B-110 back-up
lamp switch connector <M/T>.
(1) Disconnect B-109 inhibitor switch connector

<CVT, A/T> or B-110 back-up lamp switch

ACA00886

BN

Connectors: C-304, C-309, C-313
ETACS-ECU

C-313 (BR)

C-309 (B)

C-304

REVERSING SENSOR SYSTEM

CHASSIS ELECTRICAL

54A-243

connector <M/T>, and measure at the wiring
harness side.

(2) Turn the ignition switch to "ON" position.
(3) Measure the voltage between or B-109 inhibitor

switch connector <CVT, A/T> terminal (No. 8
<1600> or 3 (1800, 200)> or B-110 back-up lamp
switch connector <M/T> terminal No. 2 and earth.

OK: System voltage

Q: Is the check result normal?

YES :

Go to Step 10

NO :

Go to Step 8

STEP 8. M.U.T.-III other system service data
Check the input signal from the ignition switch (IG1)
in the ETACS-ECU.

• Turn the ignition switch to the ON position.

OK: Normal condition is displayed.

Q: Is the check result normal?

YES :

Go to Step 9.

NO :

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

STEP 9. Check the wiring harness between B-109
inhibitor switch connector terminal (No. 8 <1600>
or 3 <1800, 2000>) <CVT, A/T> or B-110 back-up
lamp switch connector <M/T> terminal No. 2 and
fusible link 34 <PETROL> or 44 <DIESEL>.

• Check the communication line for open circuit or

short circuit.

NOTE: Before the wiring harness inspection, inspect
the intermediate connectors A-11 <PETROL> or A-
60 <DIESEL> and C-31, and ETACS-ECU connec-
tors C-313 and C-309, 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 10. Check the inhibitor switch <CVT, A/T>
or back-up lamp switch <M/T>.
Check the continuity of the inhibitor switch <A/T,
CVT> or the back-up lamp switch <M/T>.(GROUP
23C

− On-vehicle Service, Inhibitor Switch Continuity

Check <A/T>, GROUP 23A

− On-vehicle Service,

Inhibitor Switch Continuity Check <CVT>, GROUP
22C

− Transmission, Transmission Inspection <M/

T>)

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 inhibitor switch <CVT, A/T> or
back-up lamp switch <M/T>.

STEP 11. Retest the system
Check if an obstacle is detected when the selector or
shift lever is shifted to the "R" (Reverse) position.

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 corner sensor/back sensor-
ECU.

CHECK AT ECU TERMINALS

M1540701400443

Item No.

Item name

Normal
condition

Item 254

IG voltage

System voltage

AC900564

C-40

AE

REVERSING SENSOR SYSTEM

CHASSIS ELECTRICAL

54A-244

Terminal
No.

Check item

Check conditions

Normal conditions

2

Sonar switch (System ON/OFF
switch)

• Ignition switch: "ON" position

• Sonar switch input: "OFF"

System voltage

• Ignition switch: "ON" position

• Sonar switch input: "ON"

1 V or less

5

Corner sensor (rear: LH)

• Ignition switch to "ON" position

• Sonar switch: ON

0V

− Approximately 8V

(40 kHz pulse signal,
emitted approx. every
125 ms)

6

Corner sensor (rear: RH)

• Ignition switch to "ON" position

• Sonar switch: ON

0V

− Approximately 8V

(40 kHz pulse signal,
emitted approx. every
125ms)

7

Back sensor (LH)

• Ignition switch to "ON" position

• Sonar switch: ON

0V

− Approximately 8V

(40kHz pulse signal,
emitted approx. every
125 ms)

8

Back sensor (RH)

• Ignition switch to "ON" position

• Sonar switch: ON

0V

− Approximately 8V

(40 kHz pulse signal,
emitted approx. every
125 ms)

11

Corner sensor OFF indicator lamp
output (System ON/OFF indicator)

• Ignition switch: "ON" position

• Sonar switch input: "OFF"

System voltage

• Ignition switch: "ON" position

• Sonar switch input: "ON"

1 V or less

12

Sensor earth 1

Always

1 V or less

13

Power supply to the ignition switch
(IG2)

Ignition switch: "ON" position

System voltage

19

CAN-H

−

−

20

CAN-L

−

−

21

Sensor earth 2

Always

1 V or less

22

Sensor earth 3

Always

1 V or less

23

Sensor earth 4

Always

1 V or less

24

Earth

Always

1 V or less

REVERSING SENSOR SYSTEM

CHASSIS ELECTRICAL

54A-245

REMOVAL AND INSTALLATION

M1540701600395

CORNER SENSOR

ACA00260

Section A – A

Claw

Claw

A

A

A

A

1

1

A

A

A

A

1

1

AB

<LANCER SPORTBACK>

<LANCER>

Removal Step

<<

A

>>

>>A<<

1.

Corner sensor