Mitsubishi Galant. Manual — part 595

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM(SRS)

52B-21

DIAGNOSIS
Replace the SRS-ECU. Refer to

P.52B-65

.

Q: Is any of DTC output?

YES : There is no action to be taken.
NO : This diagnosis is complete.

CODE NO.

DEFECTIVE PART

SYMPTOMS

14

Analog G-sensor

•

When the analog G-sensor is not operating

•

When the characteristics of the analog G-sensor are
abnormal

•

When the output from the analog G-sensor is
abnormal

15

Safing G-sensor (front air bag)

•

Short circuit in the safing G-sensor

16

•

Open circuit in the safing G-sensor

17

Safing G-sensor (side air bag)

•

When the safing G-sensor is not operating

•

When the characteristics of the safing G-sensor are
abnormal

•

When the output from the safing G-sensor is abnormal

31

Capacitor

•

Voltage at the capacitor terminal is higher than the
specified value for five seconds or more

32

•

Voltage at the capacitor terminal is lower than the
specified value for five seconds or more (This is not
detected if DTC No. 41 or 42 indicating battery
positive voltage drop has been output.)

45

Non-volatile memory (EEPROM)
and A/D converter

•

When the non-volatile memory (EEPROM) and A/D
converter system are abnormal

51

Driver's side air bag module
(squib ignition drive circuit)

•

Short circuit in the squib ignition drive circuit

52

•

Open circuit in the squib ignition drive circuit

54

Front passenger's side air bag
module (squib ignition drive
circuit)

•

Short circuit in the squib ignition drive circuit

55

•

Open circuit in the squib ignition drive circuit

73

Side air bag module (RH) (squib
ignition drive circuit)

•

Short circuit in the squib ignition drive circuit

74

•

Open circuit in the squib ignition drive circuit

83

Side air bag module (LH) (squib
ignition drive circuit)

•

Short circuit in the squib ignition drive circuit

84

•

Open circuit in the squib ignition drive circuit

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM(SRS)

52B-22

DTC 21 : Driver's side air bag module (squib) system fault 1
DTC 22: Driver's side air bag module (squib) system fault 2
DTC 61: Driver's side air bag module (squib) system fault for power supply circuit
DTC 62: Driver's side air bag module (squib) system fault for ground circuit

CIRCUIT OPERATION

•

The SRS-ECU judges how severe a collision is
by detecting signals from the left and right side
impact sensors and the analog G-sensor. If the
impact is over a predetermined level, the SRS-
ECU outputs an ignition signal. At this time, if the
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.

AC002974AB

Driver's Side Air Bag Module (Squib) Circuit

AC003195AB

CONNECTOR: C-44

SRS-ECU

CENTER
REINFORCEMENT

AC003196AB

CONNECTOR: C-62, C-63

CLOCK
SPRING

C-62

C-63

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM(SRS)

52B-23

DTC SET CONDITIONS

•

These DTC are output 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 shown in
the table below: However, if no diagnostic trouble
code resets, the SRS warning light will be
switched off (The diagnostic trouble code will be
retained).

TROUBLESHOOTING HINTS

•

Malfunction of the clock spring

•

Damaged wiring harnesses or connectors

•

Malfunction of the driver's side air bag module
(squib)

•

Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tools:

•

MB991502: Scan Tool (MUT-II)

•

MB991613: SRS Check Harness

STEP 1. Check the clock spring connector C-63
(1)Remove the air bag module mounting equipments and

check clock spring connector C-63.At this time, check that
there is no gap at place B shown in the illustration.(Refer to

P.52B-67

.)

Q: Are connectors correctly connected?

YES : Go to Step 2.
NO : Insert connector to the place, where there remains no

gap at place B shown in the illustration. Then go to
Step 5.

CODE NO.

SYMPTOMS

21

•

Short circuit in driver's side air bag module (squib) or harness

•

Short circuit in clock spring

22

•

Open circuit in driver's side air bag module (squib) or harness

•

Open circuit in clock spring

•

Malfunction of connector contact

61

•

Short circuit in driver's side air bag module (squib) harness leading to the power
supply

62

•

Short circuit in driver's side air bag module (squib) harness leading to the ground

AC002016

A

A

B

CLOCK SPRING
CONNECTOR: C-63

INFLATOR CASE

AE

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM(SRS)

52B-24

STEP2. Check the driver's side air bag module line using
the scan tool and MB991613 SRS Check harness.
(1)Remove the driver's side air bag module.(Refer to

P.52B-

67

.)

(2)Connect connector (4) of special tool MB991613 to clock

spring connector C-63.

(3)Connect connector (1) of special tool MB991613 to

connector (2).

(4)Connect terminals 22 to 24, and terminals 23 to 25 of

special tool MB991613 connector (5).

(5)Connect the clock spring to the body wiring harness.
(6)Connect the negative battery terminal.
(7)Erase the DTC memory.

Q: Is any of code number 21, 22, 61 or 62 output?

YES : Go to Step 3.
NO : Replace the driver's side air bag module. Refer

to

P.52B-67

. Then go to Step 5 .

STEP 3. Check the clock spring.
(1)Check the connectors and protective tube for damaged,

and the terminal for deformation.

(2)Visually check the case for damaged.

Q: Is any malfunction found on the clock spring?

YES : Replace the clock spring. Refer to

P.52B-67

. Then go

to Step 5.

NO : Go to Step 4.

AC003197AB

1

2

4

5

A

VIEW A

MB991613

RESISTOR (3

Ω

)

C-63

CLOCK SPRING

CONNECT, REPECTIVELY