Mitsubishi Grandis. Manual — part 991

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-16

B1474

*5

Seat belt pre-tensioner
(LH) squib drive circuit shorted

P.52B-142

B1475

*5

Seat belt pre-tensioner
(LH) squib drive circuit open

P.52B-142

B1476

*2

Power supply voltage (IG1 (A) voltage) drops abnormally.

P.52B-157

B1477

*2

Power supply voltage (IG1 (B) voltage) drops abnormally.

P.52B-157

B1478

*5

SRS-ECU capacitor circuit voltage too high

P.52B-142

B1479

*5

SRS-ECU capacitor circuit voltage too low

P.52B-142

B1480

*3

Driver's air bag (2nd squib) short-circuited

P.52B-18

B1481

*3

Driver's air bag (2nd squib) open-circuited

P.52B-24

B1482

*3

Driver's air bag (2nd squib) drive circuit (earth side)
short-circuited

P.52B-28

B1483

*3

Driver's air bag (2nd squib) drive circuit (power supply side)
short-circuited

P.52B-33

B1484

*5

Driver's air bag (2nd squib) activating circuit short-circuited

P.52B-142

B1485

*5

Driver's air bag (2nd squib) activating circuit open-circuited

P.52B-142

B1488

*5

Passenger’s air bag OFF indicator light circuit malfunction

P.52B-166

B1489

*3

Passenger’s air bag OFF
indicator light circuit
open-circuited

Light does not illuminate

*2

P.52B-170

Light does not switch off

P.52B-178

B1490

*3

Passenger's (front) air bag (2nd squib) short-circuited

P.52B-43

B1491

*3

Passenger's (front) air bag (2nd squib) open-circuited

P.52B-49

B1492

*3

Passenger's (front) air bag (2nd squib) drive circuit (earth
side) short-circuited

P.52B-52

B1493

*3

Passenger's (front) air bag (2nd squib) drive circuit (power
supply side) short-circuited

P.52B-56

B1494

*5

Passenger's (front) air bag (2nd squib) activating circuit
short-circuited

P.52B-142

B1495

*5

Passenger's (front) air bag (2nd squib) activating circuit
open-circuited

P.52B-142

B1496

*5

SRS-ECU non-volatile memory (EEPROM)

P.52B-142

B1497

*5

SRS-ECU ASIC (for frontal activation)

P.52B-142

B1498

*5

SRS-ECU ROM or RAM

P.52B-142

B1499

*5

Collision decision

P.52B-181

B1506

*3

Seat slide sensor circuit open

P.52B-182

B1507

*3

Seat slide sensor circuit (earth side) shorted

P.52B-185

B1508

*3

Seat slide sensor circuit (power supply side) shorted

P.52B-188

B1509

*2

Incorrect SRS-ECU

P.52B-191

Code No.

Diagnosis item

Reference Page

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-17

NOTE:

*1

: Electrically Erasable Programmable ROM

*2

: This diagnosis code will remain in memory and the SRS warning lamp will be switched off when the

system returns to normal condition.

*3

: This diagnosis code will remain in memory and the SRS warning lamp will be switched on even if the

system returns to normal condition.

*4

: This diagnosis code will remain in memory when the front passenger's air bag is inactive condition in the

event of an impact.

*5

: This diagnosis code cannot be erased by "Erase diagnosis codes" function.

B1519

*3

SRS-ECU connector lock out of order

P.52B-191

B1547

*4*5

Cut OFF for passenger’s front air bag

P.52B-193

B1548

*3

Can communication impossible

P.52B-142

B1549

*3

Can communication error

P.52B-142

B1552

*5

Changing circuit shorted

P.52B-142

B1553

*5

Changing circuit open

P.52B-142

B1554

*5

SG BY-PASS circuit malfunction

P.52B-142

B1555

*5

SG BY-PASS circuit (FET) open

P.52B-142

B1556

*3

Seat slide sensor malfunction

P.52B-193

B1557

*5

SRS-ECU ASIC

P.52B-142

B1570

*3

Passenger’s air bag cut off switch malfunction

P.52B-195

B1571

*3

Passenger’s air bag cut off switch circuit open (for N/C
terminal)

P.52B-195

B1572

*3

Passenger’s air bag cut off switch circuit (earth side) shorted
(for N/C terminal)

P.52B-195

B1573

*3

Passenger’s air bag cut off switch circuit (power supply side)
shorted (for N/C terminal)

P.52B-195

B1574

*3

Passenger’s air bag cut off switch circuit open (for N/O
terminal)

P.52B-195

B1575

*3

Passenger’s air bag cut off switch circuit (earth side) shorted
(for N/O terminal)

P.52B-195

B1576

*3

Passenger’s air bag cut off switch circuit (power supply side)
shorted (for N/O terminal)

P.52B-195

B1577

*3

Passenger’s air bag cut off switch circuit open (for COM
terminal)

P.52B-195

B1578

*3

Passenger’s air bag cut off switch circuit (earth side) shorted
(for COM terminal)

P.52B-195

B1579

*3

Passenger’s air bag cut off switch circuit (power supply side)
shorted (for COM terminal)

P.52B-195

B1581

*2

Incorrect passenger’s air bag cut off switch

P.52B-195

U1073

*2

Bus-off

P.52B-198

Code No.

Diagnosis item

Reference Page

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-18

DIAGNOSTIC TROUBLE CODE
PROCEDURES

Code No.B1400: Driver’s Air Bag Module (1st Squib) System Fault 1 (Short Circuit between Terminals
of the Squib Circuit)
Code No.B1480: Driver’s Air Bag Module (2nd Squib) System Fault 1 (Short Circuit between Terminals
of the Squib Circuit)

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

AIR BAG MODULE
(SQUIB)
(DRIVER'S SIDE)

CLOCK
SPRING

SRS-ECU

: CONNECTOR LOCK SWITCH
CONNECTOR CONNECTED: ON
CONNECTOR DISCONNECTED: OFF

NOTE

CONNECTOR
LOCK SWITCH

Driver's Air Bag Module (1st and 2nd Squib) Circuit

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-19

CAUTION

If diagnosis code B1400 <1st squib> or B1480
<2nd squib> is set in the SRS-ECU, always
diagnose the CAN bus lines.

OPERATION

• The SRS-ECU judges how severe a collision is

by detecting signals from the front impact sensors
and the front air bag analog 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.

• The ignition signal is input to the air bag module

via the clock spring to inflate the air bag.

DIAGNOSIS CODE SET CONDITIONS

• This diagnosis code is set if there is abnormal

resistance between the input terminals of the
driver's side air bag module (squib). The most
likely causes for this code to be set are the
followings:

• Short circuit in driver’s air bag module (squib)

or harness

• Short circuit in the clock spring

However, if no diagnosis code reset, the SRS
warning lamp will be turned off (diagnosis code will
OK).

PROBABLE CAUSES

• Improper engaged connector or defective short

spring*

• Short circuit in the clock spring

• Short circuit between the driver's air bag module

(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).
(Refer to

P.52B-5

). Therefore, if connector C-119,

C-309 or C-303 is damaged or improperly engaged,
the short spring may not be released when the
connector is connected.

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. MUT-III diagnosis code

CAUTION

To prevent damage to MUT-III, always turn the
ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting MUT-III.
(1) Turn the ignition switch to the "ON" position.
(2) Check if the diagnosis code is set.
(3) Turn the ignition switch to the "LOOK" (OFF)

position.

Q: Is diagnosis code B1519 set?

YES :

Go to Step 4.

NO :

Go to Step 5.

STEP 4. Connector check: SRS-ECU connector
C-119.

Q: Is the connector correctly engaged?

YES :

Go to Step 5.

NO :

Engage the connector correctly. Then go to
Step 10.

AC311438 AD

C-119 (Y)

Connector: C-119

Harness side
(front view)