Mitsubishi L200. Manual — part 638

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-223

Code No.B1595: Front impact sensor RH system (short circuit in the sensor)

Code No.B1596: Front impact sensor RH system (open circuit in the sensor)

Code No.B1597: Front impact sensor RH (short circuited in the earth)

Code No.B1598: Front impact sensor RH (short circuited in the power supply)

Code No.B1599: Front impact sensor LH system (short circuit in the sensor)

Code No.B1600: Front impact sensor LH (open circuit in the sensor)

Code No.B1601: Front impact sensor LH (short circuited in the earth)

Code No.B1602: Front impact sensor LH (short circuited in the power supply)

AC903656

Front Impact Sensor Circuit

SRS-ECU

FRONT IMPACT
SENSOR (RH)

FRONT IMPACT
SENSOR (LH)

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

AB

NOTE

: RHD

: LHD

OPERATION

• When the left and right front impact sensors

detect a collision, the switches inside the sensors
turn ON.

• SRS-ECU judges how severe a collision is by

detecting signals from the front impact sensors
and the front air bag analogue G-sensor. If the
impact is over a predetermined level, the SRS-
ECU sends an ignition signal. At this time, if the
front air bag safing G-sensor is on, the SRS air
bag will inflate.

DIAGNOSIS CODE SET CONDITIONS
These diagnosis codes are set if these are abnormal
resistance between the input terminals of the front
impact sensors.
The most likely causes for these codes to be set are
shown in the table below:

Code No.

Trouble causes

B1595

Right front impact sensor or its wiring shorted

B1596

Right front impact sensor or wiring open circuit

B1597

Short to body earth in the right front impact sensor harness

B1598

Short to the power supply in the right front impact sensor harness

B1599

Left front impact sensor or its wiring shorted

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-224

PROBABLE CAUSES

• Damaged harness wires and connectors

• Front impact sensor failed

• Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check the front impact sensor.
Refer to

P.52B-264

.

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Check the harness wires for open or short
circuit between intermediate connector and
front impact sensor, and repair if necessary.
Then replace the front impact sensor (Refer
to

P.52B-263

).

STEP 2. Resistance measurement at the SRS-
ECU connector C-154.
(1) Disconnect the negative battery terminal.

AC801404

AJ

Connector: C-154

C-154 (Y)

Harness side
connector
(rear view)

(2) Disconnect SRS-ECU connector C-154.

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.

AC800962 BX

C-154 Harness side
connector (rear view)

AC800962 BY

C-154 Harness side
connector (rear view)

(3) Take the measurements below at harness side

B1600

Left front impact sensor or wiring open circuit

B1601

Short to body earth in the left front impact sensor harness

B1602

Short to the power supply in the left front impact sensor harness

Code No.

Trouble causes

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-225

connector C-154.

• Resistance between terminals 29 and 30 as

well as 35 and 36.

OK: 820

± 82 Ω

AC800962 BZ

C-154 Harness side
connector (rear view)

• Continuity between terminals 29, 30, 35, 36

and body earth

OK: Open circuit

Q: Is the check result normal?

YES :

Go to Step 3.

NO :

Repair the harness wire between the front
impact sensor (RH) connector A-124
(terminals 1 and 2) and SRS-ECU
connector C-154 (terminals 36 and 35) as
well as between front impact sensor (LH)
connector A-30 (terminals 1 and 2) and
SRS-ECU connector C-154 (terminals 29
and 30).

STEP 3. Voltage measurement at the SRS-ECU
connector C-154.
(1) Disconnect the negative battery terminal.

AC801404

AJ

Connector: C-154

C-154 (Y)

Harness side
connector
(rear view)

(2) Disconnect SRS-ECU connector C-154.

(3) Connect the negative battery terminal.
(4) Turn the ignition switch to the "ON" position.

AC800963AV

C-154 Harness side
connector (rear view)

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.
(5) Take the measurements below at harness-side

connector C-154.

• Voltage between terminals 29, 30, 35, 36 and

body earth

OK: 1 V or less

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Repair the harness wire between the front
impact sensor (RH) connector A-124
(terminals 1 and 2) and SRS-ECU
connector C-154 (terminals 36 and 35) as
well as between front impact sensor (LH)
connector A-30 (terminals 1 and 2) and
SRS-ECU connector C-154 (terminals 29
and 30).

STEP 4. Check whether the diagnosis code is
reset.
Check again if the diagnosis code is set.

Q: Is diagnosis code B1595, B1596, B1597, B1598,

B1599, B1600, B1601 or B1602 set?
YES :

Replace the SRS-ECU (Refer to

P.52B-

266

).

NO :

An intermittent malfunction is suspected
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction ).

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-226

Code No.B1603: Seat belt pre-tensioner (driver's side) (squib) system (short-circuited between
terminals of the squib circuit)

AC806068

Seat Belt Pre-tensioner (Driver's Side) (Squib)

SRS-ECU

CONNECTOR
LOCK SWITCH

CONNECTOR
LOCK SWITCH

NOTE

: CONNECTOR COUPLED: ON
CONNECTOR UNCOUPLED: OFF

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

AB

SEAT BELT
PRE-TENSIONER

<LHD>
<RHD>

OPERATION
The SRS-ECU judges how severe a collision is by
detecting signals from the front impact sensors and
the front air bag analogue G-sensor. If the impact is
over a predetermined level, the SRS-ECU sends an
ignition signal. At this time, if the front air bag safing
G-sensor is on, the seat belt pre-tensioner will
deploy.

DIAGNOSIS CODE SET CONDITIONS
This diagnosis code is set if one seat belt pre-ten-
sioner (driver's side) squib wire shorted to the other.

PROBABLE CAUSES

• Improper engaged connector or defective short

spring*

• Short circuit between the seat belt pre-tensioner

(driver's side) (squib) circuit terminals

• Damaged connector(s)

• Malfunction of the SRS-ECU

NOTE: *: The squib circuit connectors integrate a
"short" spring (which prevents the air bag from
deploying unintentionally due to static electricity by
shorting the positive wire to the earth wire in the
squib circuit when the connectors are disconnected).
Therefore, if connector C-155 or D-15 <LHD> or D-
23 <RHD> is damaged or improperly engaged, the
short spring may not be released when the connector
is connected.

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code.

Q: Is diagnosis code B1519 set?

YES :

Go to Step 2.

NO :

Go to Step 3.