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