Mitsubishi Lancer (4A9 engine). Manual — part 141

REVERSING SENSOR SYSTEM

CHASSIS ELECTRICAL

54A-226

DIAGNOSTIC FUNCTION

• During the transmission/reception operation of

each sensor, when the corner sensor/back sen-
sor-ECU detects an open circuit abnormality
between the sensor and corner sensor/back sen-
sor-ECU, the ECU sets one of the diagnosis
codes No. B252E, No. B2530, No. B2532, and
No. 2534.

TROUBLESHOOTING HINT

• Damaged harness wires and connectors

• Sensor malfunction

• Malfunction of corner sensor/back sensor-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the following connectors.
Check the following connectors:

• F-31 Rear corner sensor (RH) connector

• F-34 Rear corner sensor (LH) connector

• F-32 Back sensor (RH) connector

• F-33 Back sensor (LH) connector

• C-40 corner sensor/back sensor-ECU connector

Q: Are all the connectors in good condition?

YES :

Go to Step 2.

NO :

Repair the defective connector.

STEP 2. Check the following wiring harness.
Check the wiring harness for open circuit between
the following connectors:

• Wiring harness from F-31 Rear corner sensor

(RH) connector terminal No. 1, 2 to C-40 corner
sensor/back sensor-ECU connector terminal No.
6, 23.

• Wiring harness from F-34 Rear corner sensor

(LH) connector terminal No. 1, 2 to C-40 corner
sensor/back sensor-ECU connector terminal No.
5, 22.

• Wiring harness from F-32 Back sensor (RH) con-

nector terminal No. 1, 2 to C-40 corner sensor/
back sensor-ECU connector terminal No. 8, 12.

• Wiring harness from F-33 Back sensor (LH) con-

nector terminal No. 1, 2 to C-40 corner sensor/
back sensor-ECU connector terminal No. 7, 21.

NOTE: Prior to the wiring harness inspection, check
intermediate connectors C-27, D-17, F-18, and repair
if necessary.

Q: Are all the wiring harness wires in good condition?

YES :

Go to Step 3.

NO :

Repair the wiring harness.

STEP 3. Confirm which reversing sensor (corner
sensor/back sensor) does not detect the
obstacle.

Q: Which reversing sensor (corner sensor/back

sensor) does not detect the obstacle?
Rear corner sensor (RH) :

Go to Step 4.

Rear corner sensor (LH) :

Go to Step 5.

Back sensor (RH) :

Go to Step 6.

Back sensor (LH) :

Go to Step 7.

STEP 4. Diagnosis code recheck
Temporarily replace the rear corner sensor (RH), and
then check if the diagnosis code No. B252E is set.

Q: Is the diagnosis code set?

ACB02645

AQ

Connector: C-40

ACB02748AC

F-34 (B)

Connectors: F-31, F-32, F-33, F-34 <LANCER>

F-32 (B)

F-31 (B)

F-33 (B)

ACB02749AC

F-34 (B)

F-32 (B)

F-31 (B)

F-33 (B)

Connectors: F-31, F-32, F-33, F-34
<LANCER SPORTBACK>

REVERSING SENSOR SYSTEM

CHASSIS ELECTRICAL

54A-227

YES :

Replace the corner sensor/back sensor-

ECU.

NO :

Replace the rear corner sensor (RH).

STEP 5. Diagnosis code recheck
Temporarily replace the rear corner sensor (LH), and
then check if the diagnosis code No. B2530 is set.

Q: Is the diagnosis code set?

YES :

Replace the corner sensor/back sensor-

ECU.

NO :

Replace the rear corner sensor (LH).

STEP 6. Diagnosis code recheck
Temporarily replace the back sensor (RH), and then
check if the diagnosis code No. B2532 is set.

Q: Is the diagnosis code set?

YES :

Replace the corner sensor/back sensor-

ECU.

NO :

Replace the back sensor (RH).

STEP 7. Diagnosis code recheck
Temporarily replace the back sensor (LH), and then
check if the diagnosis code No. B2534 is set.

Q: Is the diagnosis code set?

YES :

Replace the corner sensor/back sensor-

ECU.

NO :

Replace the back sensor (LH).

REVERSING SENSOR SYSTEM

CHASSIS ELECTRICAL

54A-228

Code No. B252F Rear corner sensor (RH) error

Code No. B2531 Rear corner sensor (LH) error

Code No. B2533 Back sensor (RH) error

Code No. B2535 Back sensor (LH) error

CAUTION

Before replacing the ECU or sensor, ensure that the power supply circuit, the earth circuit and the
communication circuit are normal.

Corner Sensor/Back Sensor Circuit

CORNER SENSOR/
BACK SENSOR-ECU

REAR CORNER
SENSOR (LH)

REAR CORNER
SENSOR (RH)

BACK SENSOR
(LH)

BACK SENSOR
(RH)

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

INTERFACE CIRCUIT

REVERSING SENSOR SYSTEM

CHASSIS ELECTRICAL

54A-229

DIAGNOSTIC FUNCTION

• If any of the sensors has a malfunction, if there is

a short circuit between the sensor and corner
sensor/back sensor-ECU, or if there is an error
with the corner sensor/back sensor-ECU internal
monitor, the corner sensor/back sensor-ECU sets
one of the diagnosis codes No. B252F, No.
B2531, No. B2533, and No. 2535.

TROUBLESHOOTING HINT

• Damaged harness wires and connectors

• Sensor malfunction

• Internal monitor error of corner sensor/back sen-

sor-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the following connectors.
Check the following connectors:

• F-31 Rear corner sensor (RH) connector

• F-34 Rear corner sensor (LH) connector

• F-32 Back sensor (RH) connector

• F-33 Back sensor (LH) connector

• C-40 corner sensor/back sensor-ECU connector

Q: Are all the connectors in good condition?

YES :

Go to Step 2.

NO :

Repair the defective connector.

STEP 2. Check the following wiring harness.
Check the wiring harness for short circuit between
the following connectors:

• Wiring harness from F-31 Rear corner sensor

(RH) connector terminal No. 1, 2 to C-40 corner
sensor/back sensor-ECU connector terminal No.
6, 23.

• Wiring harness from F-34 Rear corner sensor

(LH) connector terminal No. 1, 2 to C-40 corner
sensor/back sensor-ECU connector terminal No.
5, 22.

• Wiring harness from F-32 Back sensor (RH) con-

nector terminal No. 1, 2 to C-40 corner sensor/
back sensor-ECU connector terminal No. 8, 12.

• Wiring harness from F-33 Back sensor (LH) con-

nector terminal No. 1, 2 to C-40 corner sensor/
back sensor-ECU connector terminal No. 7, 21.

NOTE: Prior to the wiring harness inspection, check
intermediate connectors C-27, D-17, F-18, and repair
if necessary.

Q: Are all the wiring harness wires in good condition?

YES :

Go to Step 3.

NO :

Repair the wiring harness.

STEP 3. Confirm which reversing sensor (corner
sensor/back sensor) does not detect the
obstacle.

Q: Which reversing sensor (corner sensor/back

sensor) does not detect the obstacle?
Rear corner sensor (RH) :

Go to Step 4.

Rear corner sensor (LH) :

Go to Step 5.

Back sensor (RH) :

Go to Step 6.

Back sensor (LH) :

Go to Step 7.

STEP 4. Diagnosis code recheck
Temporarily replace the rear corner sensor (RH), and
then check if the diagnosis code No. B252F is set.

Q: Is the diagnosis code set?

ACB02645

AQ

Connector: C-40

ACB02748AC

F-34 (B)

Connectors: F-31, F-32, F-33, F-34 <LANCER>

F-32 (B)

F-31 (B)

F-33 (B)

ACB02749AC

F-34 (B)

F-32 (B)

F-31 (B)

F-33 (B)

Connectors: F-31, F-32, F-33, F-34
<LANCER SPORTBACK>