Mitsubishi Grandis. Manual - part 1013

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-104

CAUTION

If diagnosis code B1443 is set in the SRS-ECU,
always diagnose the CAN main bus line.

OPERATION

The SRS-ECU judges how severe a collision is by
detecting signals from the side impact sensors and
the side air bag safing G-sensor. If the impact is over
a predetermined level, the SRS-ECU outputs an
ignition signal. At this time, if the side air bag safing
G-sensor is on, the curtain air bag module will
deploy.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if the curtain air bag
module squib (RH) wire(s) are short-circuited to the
power supply.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Short to the power supply in the curtain air bag

module (squib) (RH) harness

• Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. MUT-III CAN bus diagnostics

Use the MUT-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
54D, Diagnosis

P.54D-16

STEP 2. Check whether the diagnosis code is
reset.

Check again if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition: LOCK (OFF) position to ON
(3) On completion, check that the diagnosis code is

not reset.

Q: Is the diagnosis code set?

YES :

Go to Step 3.

NO :

There is an intermittent malfunction such as
poor engaged connector(s) or open circuit
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction

P.00-5

STEP 3. Check the curtain air bag module (RH).
(MUT-III diagnosis code.)
(1) Disconnect the negative battery terminal.

(2) Disconnect curtain air bag module (RH)

connector G-04. Use a flat-tipped screwdriver to
unlock the locking button at the harness side
connector by withdrawing it toward you in two
stages, and then disconnect the connector.

(3) Connect special tool dummy resistor (MB991865)

to special tool resistor harness (MB991884).

(4) Connect special tool (MB991884) to the G-04

harness side connector.

(5) Connect the negative battery terminal.
(6) Erase diagnosis code memory, and check the

diagnosis code.

Q: Is diagnosis code B1443 set?

YES :

Go to Step 4.

NO :

Replace the curtain air bag module (RH)
(Refer to

P.52B-231

AC302575AD

G-04 (B)

Connector: G-04

Harness side
(front view)

Roof centre duct

AC208384AM

G-04
Curtain air bag
module connector

Flat-tip screw
driver

Locking button

G-04
Harness side
connector

AC301553AI

MB991865
(Dummy resistor : 3

ΩΩ

MB991884
(Resistor
harness)

G-04 Harness side connector

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-105

STEP 4. Check the curtain air bag module circuit.
Voltage measurement at the SRS-ECU connector
C-118.

(1) Disconnect SRS-ECU connector C-118.

(2) Disconnect curtain air bag module (RH)

connector G-04. Use a flat-tipped screwdriver to
unlock the locking button at the harness side

connector by withdrawing it toward you in two
stages, and then disconnect the connector.

(3) Turn the ignition switch to the "ON" position.

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.
(4) Voltage measurement between C-118 harness

side connector terminals 61, 62 and body earth.

OK: 0 V

Q: Is the measured voltage within the specified

range?

YES :

Go to Step 5.

NO :

Repair the harness wire between SRS-ECU
connector C-118 (terminal No.61 and 62)
and curtain air bag module (RH) connector
G-04 (terminal No.1 and 2).

STEP 5. Check whether the diagnosis code is
reset.

Q: Is diagnosis code B1443 set?

YES :

Replace the SRS-ECU (Refer to

P.52B-223

NO :

An intermittent malfunction is suspected
(Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

P.00-5

diagnosis code B1446: Side Impact Sensor (Rear) (RH) System for Fault 1
diagnosis code B1456: Side Impact Sensor (Rear) (LH) System for Fault 1

CAUTION

If diagnosis code B1446 or B1456 is set in the
SRS-ECU, always diagnose the CAN main bus
line.

DIAGNOSIS CODE SET CONDITIONS

These diagnosis codes are set if the following
conditions are detected from the analog G-sensor
inside the side impact sensor output:

• Analogue G-sensor is not operating.

• Analogue G-sensor characteristics are abnormal.

• Analogue G-sensor output is abnormal.

PROBABLE CAUSES

Malfunction of side impact sensor (Rear) (RH) (for
diagnosis code B1446) and side impact sensor
(Rear) (LH) (for diagnosis code B1456)

AC311438 AC

C-118 (Y)

Connector: C-118

Harness side
(front view)

AC302575AD

G-04 (B)

Connector: G-04

Harness side
(front view)

Roof centre duct

AC208384AM

G-04
Curtain air bag
module connector

Flat-tip screw
driver

Locking button

G-04
Harness side
connector

AC301571

56 57

52 B

C-118
Harness side connector
(rear view)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-106

DIAGNOSIS PROCEDURE

STEP 1. MUT-III CAN bus diagnostics

Use the MUT-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
54D, Diagnosis

P.54D-16

STEP 2. Check whether the diagnosis code is
reset.

Check again if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition: LOCK (OFF) position to ON
(3) On completion, check that the diagnosis code is

not reset.

Q: Is the diagnosis code set?

YES :

Go to Step 3.

NO :

There is an intermittent malfunction such as
poor engaged connector(s) or open circuit
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction

P.00-5

STEP 3. Check the side impact sensor (Rear).
(MUT-III diagnosis code.)

Replace side impact sensor (Rear) (RH) (for
diagnosis code B1446) and side impact sensor
(Rear) (LH) (for diagnosis code B1456) (Refer to

P.52B-236

Check the diagnosis code.

Q: Is either diagnosis code B1446 or B1456 set?

YES :

Replace the SRS-ECU (Refer to

P.52B-223

NO :

The procedure is complete.

Code No.B1447: Side Impact Sensor (Rear) (RH) Power Supply Circuit System

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Gray R : Red P : Pink V : Violet

SIDE IMPACT
SENSOR (REAR: RH)

SRS-ECU

Side Impact Sensor (Rear) (RH) Circuit

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-107

CAUTION

If diagnosis code B1447 is set in the SRS-ECU,
always diagnose the CAN main bus line.

OPERATION

The side impact sensor (Rear) includes an analogue
G sensor and CPU, etc. The CPU monitors the
analogue G sensor output signal. If the CPU judges
that the curtain air bags should be deployed, it sends
a fire signal to the SRS-ECU to deploy the curtain air
bags. In addition, the CPU diagnoses the internal
components of the side impact sensor (Rear). If a
malfunction occurs, it requests the SRS-ECU to set a
diagnosis code.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code will set when the power supply
voltage to the side impact sensor (Rear) (RH)
remains less than a predetermined value for five
seconds. However, if the system returns to normal
condition, code number B1447 will be erased
automatically and the SRS warning lamp will go out.

PROBABLE CAUSES

• Damaged wiring harness or connectors

• Malfunction of the side impact sensor (Rear) (RH)

• Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. MUT-III CAN bus diagnostics

Use the MUT-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
54D, Diagnosis

P.54D-16

STEP 2. Check whether the diagnosis code is
reset.

Check again if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition: LOCK (OFF) position to ON
(3) On completion, check that the diagnosis code is

not reset.

Q: Is the diagnosis code set?

YES :

Go to Step 3.

NO :

There is an intermittent malfunction such as
poor engaged connector(s) or open circuit
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction

P.00-5

STEP 3. Check the side impact sensor (Rear)
(RH) power supply circuit. Voltage measurement
at the side impact sensor (Rear) (RH) connector
D-09.
(1) Disconnect the negative battery terminal.

(2) Disconnect side impact sensor (Rear) (RH)

connector D-09, and measure at the wiring
harness side.

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

CAUTION

Do not insert a test probe into the terminal from
its front side directly, as the connector contact
pressure may be weakened.
(5) Measure the voltage between D-09 harness side

connector terminal 2 and body earth.

OK: 9 V or more

Q: Is the check result normal?

YES :

Replace the side impact sensor (Rear)

(RH). (Refer to

P.52B-236

). Then go to Step

NO :

Go to Step 4.

AC311615 AB

D-09 (Y)

Connector: D-09

Harness side
(front view)

AC313348

D-09 Harness side
connector
(rear view)

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