2007 MITSUBISHI LANCER EVOLUTION ECU

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 -Special Tools52B-5
SPECIAL TOOLS
ToolNumberNameUse
MB991502MUT-IIsub
assemblyDReading and erasing diagnosis codes
DReading trouble period
DReading erase times
MB991865Dummy resistorChecking SRS air bag circuit
MB991866Resistor harness
MB991613SRS check
harnessChecking SRS electrical circuitry
A
B
C
DMB991223
A: MB991219
B: MB991220
C: MB991221
D: MB991222Harness set
A: Check harness
B: LED harness
C: LED harness
adapter
D: ProbeChecking continuity and measuring voltage at
SRS-ECU harness connector
MB990803Steering wheel
pullerRemoving steering wheel
MR372530SRS air bag
adapter harnessDeploying driver’s air bag module inside
vehicle

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-9
WARNING LAMP CIRCUIT CONNECTOR LOCK SWITCH
Mechanism to automatically short-circuit the power supply
terminal and the earth terminal of the warning lamp circuit
when the SRS-ECU connector is disconnected. The structure
is the same as that of squib circuit connector lock switch.
INSPECTION CHART FOR DIAGNOSIS CODES
Inspect according to the inspection chart that is appropriate for the malfunction code.
Code no.Diagnostic itemPage
14SRS-ECU front impact analog G-sensor system52B-11
15SRS-ECU front impact safing G-sensor systemShort circuit in the
sensor52B-11
16SRS-ECU front impact safing G-sensor systemOpen circuit in the
sensor
21*1Driver’s air bag module (squib) systemShort circuit between
terminals of the squib
circuit52B-12
22*1Driver’s air bag module (squib) systemOpen in the squib
circuit52B-16
24*1Front passenger’s air bag module (squib) systemShort circuit between
terminals of the squib
circuit52B-20
25*1Front passenger’s air bag module (squib) systemOpen in the squib
circuit52B-22
26*1Driver’s seat belt pre-tensioner (squib) systemShort circuit between
terminals of the squib
circuit52B-23
27*1Driver’s seat belt pre-tensioner (squib) systemOpen in the squib
circuit52B-25
28*1Front passenger’s seat belt pre-tensioner (squib) systemShort circuit between
terminals of the squib
circuit52B-26
29*1Front passenger’s seat belt pre-tensioner (squib) system/Open in the squib
circuit52B-28
31SRS-ECU DC-DC converter systemIncreased terminal
voltage52B-11
32SRS-ECU DC-DC converter systemDecreased terminal
voltage
Ignition switch (IG1)
SRS warning lamp
SRS-ECU harness
side connector
Short spring
ON
ONOFF
OFF Connector*
lock switch
NOTE
*:connector engaged:ON
connector disengaged:OFF

SRS -Troubleshooting52B-10
Code no.Page Diagnostic item
34*2Connector lock system52B-29
35SRS-ECU (deployed air bag) system52B-29
41*2Power supply circuit system (fuse No.2 circuit)52B-30
42*2Power supply circuit system (fuse No.3 circuit)52B-32
43*2SRS warning lamp drive circuit systemLamp does not illumi-
nate.52B-33
SRS warning lamp drive circuit systemLamp does not go out.52B-33
44*2SRS warning lamp drive circuit system52B-33
45SRS-EUC internal circuit system including non - volatile memory (EEPROM)52B-11
51Driver’s air bag module (squib) ignition drive circuit systemShort in the ignition
drive circuit52B-11
52Driver’s air bag module (squib) ignition drive circuit systemOpen in the ignition
drive circuit
54Front passenger’s air bag (squib) ignition drive circuit
systemShort in the ignition
drive circuit52B-11
55Front passenger’s air bag (squib) ignition drive circuit
systemOpen in the ignition
drive circuit
56Driver’s seat belt pre-tensioner (squib) ignition drive circuit
systemShort in the ignition
drive circuit52B-11
57Driver’s seat belt pre-tensioner (squib) ignition drive circuit
systemOpen in the ignition
drive circuit
58Front passenger’s seat belt pre-tensioner (squib) ignition
drive circuit systemShort in the ignition
drive circuit52B-11
59Front passenger’s seat belt pre-tensioner (squib) ignition
drive circuit systemOpen in the ignition
drive circuit
61Driver’s air bag module (squib) systemShort-circuited to
power supply52B-34
62Driver’s air bag module (squib) systemShort-circuited to earth
64Front passenger’s air bag module (squib) systemShort-circuited to
power supply52B-38
65Front passenger’s air bag module (squib) systemShort-circuited to earth
66Driver’s seat belt pre-tensioner (squib) systemShort-circuited to
power supply52B-39
67Driver’s seat belt pre-tensioner (squib) systemShort-circuited to earth
68Front passenger’s seat belt pre-tensioner (squib) systemShort-circuited to
power supply52B-40
69Front passenger’s seat belt pre-tensioner (squib) systemShort-circuited to earth
NOTE
(1) *1: If the trouble(s) are removed, the SRS warning lamp go out with diagnosis code history stored.
(2) *2: If the trouble(s) are removed, the SRS warning lamp will go out with diagnosis code history automatically erased.
(3) When the battery has been discharged, diagnosis code No.41 or 42 is stored. Check the battery when either of
these is displayed.

SRS -Troubleshooting52B-11
INSPECTION PROCEDURE CLASSIFIED BY DIAGNOSIS CODE
Code No.14, 15, 16, 31, 32, 45, 51, 52, 54, 55, 56, 57, 58, 59
System inside SRS-ECUProbable cause
Malfunction is present inside SRS-ECU. See table below for what each code
tells.DMalfunction of SRS-ECU
Code No.Defective partsTrouble
14Front impact analog G-sensorDNot operating
DAbnormal characteristics
DAbnormal output
15Front impact safing G-sensorDShort in the circuit
16DOpen in the circuit
31DC-DC converterDTerminal voltage of the converter higher than specified for
five seconds or more
32DTerminal voltage of the converter lower than specified for
5 seconds or more (this code is not detected when code
No.41 or 42, which indicates discharged battery, has been
detected)
45Non-volatile memory (EEPROM)DDefective parts inside
51Driver’sairbagmodule(squib)DShortinthecircuit51Driver’sairbag module(squib)
ignitiondrivecircuit
DShortinthecircuit
52ignition drive circuitDOpen in the circuit
54Front passenger’s air bag module
(squib)ignitiondrivecircuit
DShort in the circuit
55(squib)ignitiondrive circuitDOpen in the circuit
56Driver’s seat belt pre-tensioner
(squib)ignitiondrivecircuit
DShort in the circuit
57(squib)ignitiondrive circuitDOpen in the circuit
58Front passenger’s seat belt pre-ten-
sioner(squib)ignitiondrivecircuit
DShort in the circuit
59sioner(squib)ignitiondrive circuitDOpen in the circuit
If the above - mentioned code No. is output, replace the SRS-ECU.