2007 MITSUBISHI LANCER EVOLUTION clock

SRS -General InformationSRS -General Information52B-2
GENERAL INFORMATION
To improve safety, the SRS and seat belts with
pre-tensioner. These systems enhance collision
safety by restraining the front passengers in case
of an accident. The SRS works with the
pre-tensioner simultaneously when a collision is
detected.
The SRS consists of two air bag modules, SRS
air bag control unit (SRS-ECU), SRS warning lamp
and clock spring. The air bags are located in the
center of the steering wheel, above the glove box.
Each air bag has a folded air bag and an inflator
unit. The SRS-ECU under the floor console monitors
the system and has a safing G-sensor and an
analog G-sensor. The warning lamp on theinstrument panel indicates the operational status
of the SRS. The clock spring is installed in the
steering column. The seat belt pre-tensioner is built
into the front seat belt retractor. Only authorized
service personnel should do work on or around
the SRS components and seat belt with
pre-tensioner. Those service personnel should read
this manual carefully before starting any such work.
Extreme care must be used when servicing the
SRS to avoid injury to the service personnel (by
inadvertent deployment of the air bags or
inadvertent operation of the seat belt with
pre-tensioner) or the driver (by rendering the SRS
or the seat belt with pre-tensioner inoperative).
Diagnosis
connectorFront passenger’s
air bag module
Clock spring Driver’s air bag
module
SRS-ECU
SRS warning lamp
Driver’s air bag
Front
passenger’s
air bag
Seat belt with
pre-tensioner

SRS -SRS Service Precautions52B-3
SRS SERVICE PRECAUTIONS
1. In order to avoid injury to yourself or others
from accidental deployment of the air bag and
accidental operation of the seat belt with
pre-tensioner during servicing, read and
carefully follow all the precautions and
procedures described in this manual.
2. Do not use any electrical test equipment on
or near SRS components, except those
specified on P.52B-6.
3. Never Attempt to Repair the Following
Components:
DSRS air bag control unit (SRS-ECU)
DClock spring
DDriver’s and front passenger’s air bag
modules
DSeat belt with pre-tensionerNOTE
If any of these components are diagnosed as
faulty, they should only be replaced, in
accordance with the INDIVIDUAL COM-
PONENTS SERVICE procedures in this
manual. (Refer to P.52B-49.)
4. After disconnecting the negative (–) battery cable,
wait 60 seconds at least before any service and
insulate the disconnected cable with tape. The SRS
retain enough voltage to deploy the air bags for a
short time even after the disconnection of the battery.
So, serious injury may result by accidental air bag
deployment if a work is done on the SRS just after
the disconnection of the battery.
5. Do not attempt to repair the wiring harness connectors
of the SRS. If the connector(s) are diagnosed as defective,
replace the wiring harness(es). If the harness(es) are
diagnosed as faulty, replace or repair the wiring
harness(es) according to the table that follows.
Insulating tape
Battery
SRS-ECU connector

SRS -SRS Service Precautions52B-4
SRS-ECU
Terminal No.Destination of harnessCorrective action
7Instrument panel wiring harness→EarthRepair or replace each wiring
harness
8Instrument panel wiring harness→Combination meter
(SRS warning lamp)
harness
9, 10Instrument panel wiring harness→Front passenger’s air bag
module
11 , 1 2Instrument panel wiring harness→Clock spring→Driver’s air bag
module)Repair or replace the dash wiring
harness. Replace clock spring.
13Instrument panel wiring harness→Junction block (fuse No.3)Repair or replace each wiring
harness
16Instrument panel wiring harness→Junction block (fuse No.2)
harness.
20Instrument panel wiring harness→Diagnosis connector
29, 30Floor wiring harnessàDriver’s seat belt pre-tensioner
27, 28Floor wiring harnessàFront passenger’s seat belt pre-tensioner
6. Inspection of the SRS-ECU harness connector should be carried out by the following procedure.
Insert the special tool (probe, MB991222, in the harness set) into the connector from harness side
(rear side), and connect the tester to this probe. If any tool than specified is used, damage to the
harness and other components will result. Furthermore, measurement should not be carried out by
touching the probe directly against the terminals from the front of the connector. The terminals are
plated to increase their conductivity, so that if they are touched directly by the probe, the plating
may break, which will cause drops in reliability.
MB991222 SRS-ECU harness connector
SRS-ECU harness connector (rear view)
7. SRS components and seat belt with pre-tensioner should not be subjected to hart, so remove the
SRS-ECU, driver’s and front passenger’s air bag modules, clock spring, and seat belt with pre-tensioner
before drying or baking the vehicle after painting.
DSRS - ECU, air bag module, clock spring : 93Æ
or more
DSeat belt with pre-tensioner : 90Æ
or more
8. Whenever you finish servicing the SRS, check warning lamp operation to make sure that the system
functions properly. (Refer to P.52B-6.)
9. Make certain that the ignition switch is LOCK (OFF) position when the MUT-IIis connected or
disconnected.
10. If you have any questions about the SRS, please contact your local distributor.
NOTE
SERIOUS INJURY CAN RESULT FROM UNINTENDED AIR BAG DEPLOYMENT, SO USE ONLY
THE PROCEDURES AND EQUIPMENT SPECIFIED IN THIS MANUAL.

SRS -Troubleshooting52B-7
SRS SYSTEM CIRCUIT DIAGRAM
Ignition switch (IG1)
J/B
(common fuse)
Combination
Meter
Connector lock switch*
ON
ON OFF
OFF
Driver’s air
bag module
(squib)
Front pas-
senger’s seat
air bag mod-
ule(squib)
Seat belt
pre-tensioner
(L.H.)Clock spring
ONONOFF
OFF
Connector lock switch* Diagnosis connector SRS-ECU
No.3
7.5A No.2
7.5A
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFFON
ON
ON
ON
ON
ON
ON
ONOFF
ON
ON OFF
C-207
C-204
C-109
D-28
D-26C-22
SRS - ECU connector16
13
7 8
11
12
10
9
30
29
28
2720 Connector lock switch*
Connector lock switch*
Connector lock switch*
Connector lock switch*
Connector lock switch*
NOTE
*:connector engaged:ON
connector disengaged:OFF Seat belt
pre-tensioner
(R.H.)

SRS -Troubleshooting52B-8
CONNECTOR FOR SRS AIR BAG
The SRS air bag system connector is yellow or red.
To enhance system reliability, a connector lock switch is adopted for the SRS-ECU connector, and each
air bag module and clock spring connector, each seat belt with pre-tensioner following illustration (black)>).
AClock
spring
SRS-ECUDriver’s air bag module
Front passenger’s air bag module A
A ADriver’s seat belt pre-tensioner
Front passenger’s seat belt pre-tensioner
SQUIB CIRCUIT CONNECTOR LOCK SWITCH
Mechanism to automatically short-circuit the power supply terminal and the earth terminal of the air bag squib
circuit when the connector is disconnected. The short spring inside the connector allows to short-circuit the
power supply terminal and the earth terminal of the squib (no difference in voltage occurs between the
terminals) to prevent the squib from getting charged with static electricity.
CAUTION
When the connector is disconnected, it is normal for short-circuiting to occur between the connector
terminals.
When connector is connected
When connector is disconnectedOFF
ON
OFFOFF
OFF
ONON
ON
ECU side connectorHarness side connector
A A
Short spring
Partition panelTerminal
(Female) Terminal
(Male)B
BSection A - A
Section B - B
Partition
panelShort springTerminal
(Female)
Terminal
(Male)When connector is connected
Partition panel
Terminal
(Female) Te r m i n a l
(Male) SquibSquib
SRS-ECUSRS-ECU
Short spring

SRS -Troubleshooting52B-12
Code No.21 Driver’s air bag module (squib) systemPossible Cause
This code is output when short circuit occurs between terminals of the
SRS-ECU driver’s air bag module (squib) circuit.
However, SRS warning lamp goes out when a normal operation is resumed
(diagnosis code is not cleared.)DConnector engagement faulty or short bar faulty*
DShort circuit in the clock spring
DShort circuit between terminals of the driver’s air
bag module (squib) circuit
DFaulty connector
DSRS-ECU inoperable
NOTE:
(1) *: The connector of the squib circuit contains a short bar (short-circuiting the positive (+) cable and
the negative ( - ) cable to avoid an erroneous deployment caused by static electricity when a connector
is not connected). Thus, when a connector is connected, the short bar may not be released due
to improper engagement of the connector or faulty connector as shown in the illustration below.
Disconnect the connector as shown in the illustration below, then reconnect it. Check that a diagnosis
code is output again after erasing the memory. If the diagnosis code is not output, the above-mentioned
code is output due to improper engagement of the connector.
C-204C-207
SRS-ECU
Clock spring
Driver’s air bag module C-21
(2) Two different types of driver’s air bag modules by model are featured. Thus, two types of air bag
module by model are described in the following flowchart.
RS: Steering wheel and air bag module separate type
RS-II: Steering wheel and air bag module incorporate type

SRS -Troubleshooting52B-13

NG
spring>
Measure at the SRS-ECU connector C - 21.
DDisconnect the SRS-ECU connector C-21.
DRelease the the clock spring connector C-204.
Caution
Disconnect the connector and short-circuit the squib
circuit before releasing the short bar of the SRS-ECU
connector in the following operation.
DCable bands between terminals 11, 12 and the short bar
(width:3 mm, thickness:0.5 mm) between terminals 11 and
12 and the short bar, and release the short bar.
(See Figure A.)
Caution
As the short bar may not be releasable if inserted
insufficiently, insert more than 4 mm.
DMeasure at the harness side
DContinuity check between terminals 11 and 12
Caution
Do not directly insert a probe or other devices at the
front of the connector to avoid a possible decrease in
the contact pressure.
OK:No continuity
Check connector:C-21, C-204
MUT-II self-diag code
DRelease the clock spring connector (2 - pin) C-204.
DConnect the dummy resistor (MB991865) to the resistor harness
(MB991866).
DInsert the resistor harness
(MB991866) behind the harness side connector C-204.
Caution
Do not directly insert a probe or other devices at the front of the
connector to avoid a possible decrease in the contact pressure.
DConnect the negative ( - ) terminal of the battery
DCheck the diagnosis code again after erasing the memory.
Is code No.21 output?
Resistor harness
(MB991866)
C - 204 clock spring
harness side connector
YES Dummy resistor
(MB991865)
resistance (3Ω)
Check the clock spring (Refer to P.52B-59.)
NOYES
Replace the clock spring.Replace the driver’s air bag module
(squib).NO
Check the harness between the clock spring and the
SRS-ECU, and repair if necessary.
Check the trouble
symptoms.Correct
OK
NG NG
Replace the SRS-ECU.
OK
Figure A
Terminal
Short bar
Front view of SRS-ECU
connector C-21
(harness side)
Cable band
and etc.Section
A-A
4 mm or more
A
AConnector C-21

SRS -Troubleshooting52B-14


MUT-II self-diag code
DDisconnect the clock spring connector No.1 (connector connected with
the air bag module).
DConnect the dummy resistor (MB991865) to the resistor harness
(MB991866).
DInsert the resistor harness (MB991866) behind the clock spring
connector No.1.
Caution
Do not directly insert a probe or other devices at the front of the
connector to avoid a possible decrease in the contact pressure.
DConnect the negative ( - ) terminal of the battery
DCheck the diagnosis code again after erasing the memory.
Is code No.21 output? Dummy resistor
(MB991865)
resistance (3Ω)
1
YESNO
Replace the driver’s air bag module (squib). Resistor harness
(MB991866)
Go to Next Page
MUT-II self-diag code
DRelease the clock spring connector (2 - pin) C-204 .
DConnect the dummy resistor (MB991865) to the resistor harness.
DInsert the resistor harness
(MB991866) behind the harness side connector C-204 .
Caution
Do not directly insert a probe or other devices at the front of the
connector to avoid a possible decrease in the contact pressure.
DConnect the negative ( - ) terminal of the battery
DCheck the diagnosis code again after erasing the memory.
Is code No.21 output?
YESNO
Replace the clock spring. Resistor harness
(MB991866)
Clock spring harness
side connector C-204 Dummy resistor
(MB991865)
resistance (3Ω)