2007 MITSUBISHI LANCER EVOLUTION ECU

SRS -Troubleshooting52B-22
Code No.25 Front passenger’s air bag module (squib)
systemPossible Cause
This code is output when open circuit occurs in the SRS-ECU front passenger’s
air bag (squib) circuit.
However, SRS warning lamp goes out when a normal operation is resumed
(diagnosis code is not cleared.)DOpen in the front passenger’s air bag module
(squib) circuit
DConnector improper contact
DSRS-ECU inoperable
NG
passenger’s air bag module>
Measure at the SRS-ECU connector C-21 and front
passenger’s air bag module connector C-109 .
DDisconnect the SRS-ECU connector C-21 and the front
passenger’s air bag module connector C-109 , and
measure at the harness side.
DContinuity check between the following terminals
Connector C-21 Connector C-109
9–2
10 – 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.
OK:Continuity (2Ωor less)
YESNO
Replace the front passenger’s seat air bag module (squib).

MUT-II self-diag code
DConnect the dummy resistor (MB991865) to the resistor harness
(MB991866).
DDisconnect the front passenger’s air bag module connector C-109
and insert the resistor harness (MB991866) behind the harness side
connector.
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.25 output?
Replace the SRS-ECU.
Check the trouble
symptoms.
NG
Check the harness between the front passenger’s air bag
module and the SRS-ECU, and repair if necessary.
OKNG
Correct
Check connector:C-21, C-109
OK
Resistor harness
(MB991866) Dummy resistor
(MB991865)
resistance (3Ω)
Instrumental panel
wiring harness
Front passenger’s air bag
module connector
Connector C-21Connector C-109

SRS -Troubleshooting52B-23
Code No.26 Driver’s seat belt pre-tensioner (squib)
systemPossible Cause
This code is output when short circuit occurs between terminals of the
SRS-ECU driver’s seat belt pre-tensioner (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 between terminals of the driver’s seat
belt pre-tensioner (squib) circuit
DFaulty connector
DSRS-ECU inoperable
NOTE:
*: 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-41C-133*1,
C-112*2
SRS-ECU
Driver’s seat belt
pre-tensioner
NOTE
*1: L.H. drive vehicles
*2: R.H. drive vehicles
D-28*1,
D-26*2

SRS -Troubleshooting52B-24
OK
YESNO
Replace the driver’s seat belt pre-tensioner.

MUT-II self-diag code
DConnect the dummy resistor (MB991865) to the resistor harness
(MB991866).
DDisconnect the driver’s seat belt pre-tensioner connector D-28*
1and
D-26*2and connect to the resistor harness (MB991866) behind the
harness side connector.
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.26 output?
Replace the SRS-ECU.
Check the trouble
symptoms.
NG
Check the harness between the driver’s seat belt
pre-tensioner and the SRS-ECU, and repair if necessary.
YESNG
Correct
Check connector:D-28*1,D-26*2,C-133*1, C-112*2, C-41 Driver’s seat belt
pre-tensioner connector
seat belt pretensioner>
Measure at the SRS-ECU connector C-41.
DDisconnect the SRS-ECU connector C-41.
DDisconnect the driver’s seat belt pre-tensioner connector
D-28*
1and D-26*2.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 29, 30 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 29 and 30
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 continuityResistor harness
(MB991866) Dummy resistor (MB991865)
resistance (3Ω)
Instrumental panel
wiring harness
Connector C-41NG
Figure A
Terminal
Short bar
Front view of SRS-ECU
connector C-41
(harness side)
Cable
band and etc.Section
A-A
4 mm or more
A
A
NOTE
*1: L.H. drive vehicles
*2: R.H. drive vehicles

SRS -Troubleshooting52B-25
Code No.27 Driver’s seat belt pre-tensioner (squib)
systemPossible Cause
This code is output when open circuit occurs in the SRS-ECU driver’s seat belt
pre-tensioner (squib) circuit.
However, SRS warning lamp goes out when a normal operation is resumed
(diagnosis code is not cleared.)DConnector improper contact
DOpen in the driver’s seat pre-tensioner (squib)
circuit
DSRS-ECU inoperable

MUT-II self-diag code
DConnect the dummy harness (MB991865) to the resistor harness
(MB991866).
DDisconnect the driver’s seat belt pre-tensioner connector D-28*
1and
D-26*2and insert the resistor harness (MB991866) behind the harness
side connector.
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.27 output?
YESNO
Replace the driver’s seat belt pre-tensioner.
Replace the SRS-ECU.
Check the trouble
symptoms.
NG
Check the harness between the driver’s seat belt pre-tensioner
and the SRS-ECU, and repair if necessary. NG
OK
OKNG
Correct
Check connector:D-28*1,D-26*2, C-133*1, C-112*2, C-124 Driver’s seat belt
pre-tensioner connector
seat belt pretensioner>
Measure at the SRS-ECU connector C-41, the driver’s seat
belt pre-tensioner connector D-28*
1and D-26*2.
DDisconnect the SRS-ECU connector C-41 , the driver’s
seat belt pre-tensioner connector D-28*1and D-26*2, and
then measure at the harness side.
DContinuity check between the following terminals
Connector C-41 D-28*
1,D-26*2
29 – 2
30 – 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.
OK:Continuity (2Ωor less)Resistor harness
(MB991866) Dummy resistor
(MB991865)
resistance (3Ω)
Instrumental panel
wiring harness
Connector C-41D-28*
1,D-26*2connector
NOTE
*1: L.H. drive vehicles
*2: R.H. drive vehicles

SRS -Troubleshooting52B-26
Code No.28 Front passenger’s seat belt pre-tensioner
(squib) systemPossible Cause
This code is output when short circuit occurs between terminals of the
SRS-ECU front passenger’s seat belt pre-tensioner (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 between terminals of the front
passenger’s seat belt pre-tensioner (squib) circuit
DFaulty connector
DSRS-ECU inoperable
NOTE
*: 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-41C-133*1,
C-112*2D-28*1,
D-26*2
SRS-ECUFront passenger’s seat
belt pre-tensioner
NOTE
*1: L.H. drive vehicles
*2: R.H. drive vehicles

SRS -Troubleshooting52B-27
YESNO
Replace the front passenger’s seat belt pre-tensioner.

MUT-II self-diag code
DConnect the dummy harness (MB991865) to the resistor harness
(MB991866).
DDisconnect the front passenger’s seat belt pre-tensioner connector
D-28*
1and D-26*2and insert the resistor harness (MB991866) behind
the harness side connector.
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.28 output?
Replace the SRS-ECU.
Check the trouble
symptoms.
NG
Check the harness between the front passenger’s seat belt
pre-tensioner and the SRS-ECU, and repair if necessary. NG
Figure A
Short bar
Front view of SRS-ECU
connector C-41
(harness side)
OKNG
Correct
Check connector:D-28*1, D-26*2, C-133*1, C-112*2, C-41
passenger’s seat belt pre-tensioner>
Measure at the SRS-ECU connector C-41.
DDisconnect the SRS-ECU connector C-41.
DDisconnect the front passenger’s seat belt pre-tensioner
connector D-28
*1and D-26*2
.
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 27, 28 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 27 and 28
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 continuityTerminal
Cable
band and etc.
Section
A-A
A
A
4 mm or more Resistor harness
(MB991866) Dummy resistor
(MB991865)
resistance (3Ω)
Instrumental panel
wiring harness
Front passenger’s seat belt
pre-tensioner connectorConnector C-41
OK
NOTE
*1: L.H. drive vehicles
*2: R.H. drive vehicles

SRS -Troubleshooting52B-28
Code No.29 Front passenger’s seat belt pre-tensioner
(squib) systemPossible Cause
This code is output when open circuit occurs in the SRS-ECU front passenger’s
seat belt pre-tensioner (squib) circuit.
However, SRS warning lamp goes out when a normal operation is resumed
(diagnosis code is not cleared.)DOpen in the front passenger’s seat pre-tensioner
(squib) circuit
DConnector improper contact
DSRS-ECU inoperable
passenger’s seat belt pre-tensioner>
Measure at the SRS-ECU connector C-41 , the front
passenger’s seat belt pre-tensioner connector D-28*
1and
D-26*2.
DDisconnect the SRS-ECU connector C-41 , the front
passenger’s seat belt pre-tensioner connector D-28*
1and
D-26*2, and then measure at the harness side.
DContinuity check between the following terminals
Connector C-41 D-28*
1, Connector D-26*2
28 – 2
27 – 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.
OK:Continuity (2Ωor less)
YESNO
Replace the front passenger’s seat belt pre-tensioner.

MUT-II self-diag code
DConnect the dummy harness (MB991865) to the resistor harness
(MB991866).
DDisconnect the front passenger’s seat belt pre-tensioner connector
D-28*
1and D-26*2and insert the resistor harness (MB991866) behind
the harness side connector.
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.29 output?
Replace the SRS-ECU.
Check the trouble
symptoms.
NG
Check the harness between the front passenger’s seat belt
pre-tensioner and the SRS-ECU, and repair if necessary. NG
OK
OKNG
Correct
Check connector:D-28*1, D-26*2, C-133*1, C-112*2, C-41 Resistor harness
(MB991866) Dummy resistor
(MB991865)
resistance (3Ω)
Instrumental panel
wiring harness
Front passenger’s seat belt
pre-tensioner connector
Connector C-41Connector D-28*
1, D-26*2
NOTE
*1: L.H. drive vehicles
*2: R.H. drive vehicles

SRS -Troubleshooting52B-29
Code No.34 Connector Lock SystemProbable Cause
The SRS-ECU connector is mounted with a connector lock switch terminal for
detecting the connected state of the connector.
SRS-ECU connector is poorly connected.
However, when the vehicle condition returns to normal, this code will be
automatically erased, and the SRS warning lamp will go out.DFaulby connector
DSRS-ECU inperable
NOIs the SRS-ECU connector C-21 connected properly?
Replace the SRS-ECU.Correct YES
OK
Correct the connector connection.
Check trouble symptoms. NG
NGCheck the C-21 SRS-ECU connector.
DDisconnect the connector.
DCheck the connector lock switch terminal in the harness
side connector for contact pressure and deformation, etc.
(See Figure A.)
Is the connector lock switch terminal normal?
Connector lock switch terminal
Front view of the SRS-ECU connector
(harness side)
Figure A
Code No.35 SRS-ECU (deployed air bag) systemProbable cause
This code is displayed after deployment of air bags. If displayed before
deployment, the code indicates malfunction probably present in SRS-ECU.DSRS-ECU inperable
If the above-mentioned code No. is output, replace the SRS-ECU.