Mitsubishi Galant. Manual — part 600

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM(SRS)

52B-41

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.

DTC SET CONDITIONS

•

These DTC are output if communication between
the side impact sensor (LH) and the SRS-ECU is
not possible or communication is faulty.

TROUBLESHOOTING HINTS

•

Damaged wiring harnesses or connectors

•

Malfunction of the side impact sensor (LH)

•

Malfunction of the SRS-ECU

DIAGNOSIS

Required Special Tool:

•

MB991502: Scan Tool (MUT-II)

STEP 1. Check the side impact sensor
(1)Replace the side impact sensor (LH) with the side impact

sensor (RH).

(2)Connect the negative battery terminal.
(3)Erase DTC memory.

Q: Is DTC 79 or 93 erased or DTC 89 or 96 output?

YES : Replace the side impact sensor (LH) with a new one.

Refer to

P.52B-74

. Then go to Step 3.

NO : Go to Step 2.

AC003208AB

CONNECTOR: D-23

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM(SRS)

52B-42

STEP 2. Check the harness wires between SRS-ECU
connector C-45 and side impact sensor (LH) connector D-
20.
NOTE: After inspecting intermediate connector D-23, inspect
the wiring harness. If the intermediate connector D-23 is
damaged, repair or replace it. Refer to GROUP 00E, Harness
Connector Inspection

P.00E-2

. Then go to Step 3. If harness

wires are in good condition, go to Step 3. If any harness wires
between SRS-ECU connector C-45 and side impact sensor
(LH) connector D-20 are damaged, repair them or install the
sensor cable. Refer to

P.52B-74

. Then go to Step 3.

Q: Are the harness wires between SRS-ECU connector C-

45 and side impact sensor (LH) connector D-20 in good
condition?
YES : Go to Step 3.
NO : Repair them. Then go to Step 3.

STEP 3. Check for DTC.

Q: Is any of DTC 79 or 93 output?

YES : Replace the SRS-ECU. Refer to

P.52B-65

.

NO : This diagnosis is compleate.(If no malfunctions are

not found in all steps, an intermittent malfunction is
suspected. Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

−

How to

Cope with Intermittent Malfunction.)

AC003195AD

CONNECTOR: C-45

CENTER
REINFORCEMENT

SRS-ECU

AC003207AB

CONNECTOR: D-20

AC003208AB

CONNECTOR: D-23

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM(SRS)

52B-43

DTC 81: Left hand side-air bag module (squib) system fault 1
DTC 82:Left hand side-air bag module (squib) system fault 2
DTC 85:Left hand side-air bag module (squib) system fault power squib circuit
DTC 86:Left hand side-air bag module (squib) system fault 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
to inflate the air bag.

DTC SET CONDITIONS

•

These DTC are output if communication between
the side impact sensor (LH) and the SRS-ECU is
not possible or communication is faulty.

TROUBLESHOOTING HINTS

•

Damaged wiring harnesses or connectors

•

Malfunction of the side impact sensor (LH)

•

Malfunction of the SRS-ECU

AC000824AB

Side Air Bag Module (LH) (Squib) Circuit

AC003195AD

CONNECTOR: C-45

CENTER
REINFORCEMENT

SRS-ECU

AC003209AB

CONNECTOR: C-22

DTC

SYMPTOMS

81

•

Short circuit in side air bag module (LH) (squib) or harness

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM(SRS)

52B-44

DIAGNOSIS

Required Special Tool:

•

MB991502: Scan Tool (MUT-II)

•

MB991613: SRS Check Harness

STEP 1. Check the side air bag module line using the scan
tool and MB991613 SRS Check harness.
(1)Disconnect side air bag module (LH) connector D-22.
(2)Connect special tool MB991613 connector (1).
(3)Connect the negative battery terminal.
(4)Erase DTC memory.

Q: Is any of DTC 81, 82, 85 or 86 output?

YES : Go to Step 2.
NO : Replace the seat back assembly of the front seat

(LH). Refer to GROUP 52A, Front Seat

P.52A-16

.

Then go to Step 3.

STEP 2. Check the harness wires between SRS-ECU
connector C-45 and side air bag module (LH) connector D-
22.
Q: Are the harness wires between SRS-ECU connector C-

45 and side air bag module (LH) connector D-22 in good
condition?
YES : Go to Step 3.
NO : Repair them. Then go to Step 3.

82

•

Open circuit in side air bag module (LH) (squib) or harness

•

Malfunction of connector contact

85

•

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

86

•

Short circuit in side air bag module (LH) (squib) harness leading to ground

DTC

SYMPTOMS

AC003210AB

1

MB991613

D-22

AC003195AD

CONNECTOR: C-45

CENTER
REINFORCEMENT

SRS-ECU

AC003209AB

CONNECTOR: C-22