MITSUBISHI LANCER EVOLUTION VI 1999 Workshop Manual

SRS – Special Tools / Test Equipment52B-5
SPECIAL TOOLS
ToolNumberNameUse
MB991502MUT-II sub
assembly
Reading diagnosis codes

Erasing diagnosis code

Reading trouble period

Reading erase times
MB991613SRS check
harnessChecking the SRS electrical circuitry
MB990803Steering wheel
pullerSteering wheel removal
MB686560SRS air bag
adapter harness A
Deployment of air bag modules and seat
belt with pre-tensioner inside the vehicle

Deployment of air bag module (front
passenger’s side) outside the vehicle
MR203491 or
MB628919SRS air bag
adapter harness BDeployment of air bag module (driver’s side)
outside the vehicle
TEST EQUIPMENT
ToolNameUse
Digital multi-meterChecking the SRS electrical circuitry
Use a multi-meter for which the
maximum test current is 2 mA or less
at the minimum range of resistance
measurement

SRS – Troubleshooting52B-6
TROUBLESHOOTING
STANDARD FLOW OF DIAGNOSTIC TROUBLESHOOTING
Refer to GROUP 00 – How to Use Troubleshooting/Inspection Service Points.
DIAGNOSIS FUNCTION
DIAGNOSIS CODES CHECK
Connect the MUT-II to the diagnosis connector (16-pin) under the instrument under cover, then check
diagnosis codes.
(Refer to GROUP 00 – How to Use Troubleshooting/Inspection Service Points.)
ERASING DIAGNOSIS CODES
Connect the MUT-II to the diagnosis connector and erase the diagnosis code.
Caution
Turn off the ignition switch before connecting or disconnecting the MUT-II.
INSPECTION CHART FOR DIAGNOSIS CODES
Inspect according to the inspection chart that is appropriate for the malfunction code.
Code No.Diagnosis itemReference page
14Analog G-sensor system in the SRS-ECU52B-7
15,16Safing G-sensor system in the SRS-ECU52B-7
21, 22, 61, 62Driver’s side air bag module (squib) system52B-8
24, 25, 64, 65Front passenger’s side air bag module (squib) system52B-9
31, 32SRS-ECU capacitor system52B-9
34*Connector lock system52B-10
35SRS-ECU (deployed air bag) system52B-10
41*IG1 (A) power circuit system52B-10
42*IG1 (B) power circuit system52B-11
43SRS warning lamp drive circuit
system
Lamp does not illuminate.*52B-12
systemLamp does not switch off.52B-12
44SRS warning lamp drive circuit system52B-13
45SRS-ECU non-volatile memory (EEPROM) and A/D converter system52B-13
51, 52Driver’s side air bag module (squib ignition drive circuit) system52B-13
54, 55Front passenger’s side air bag module (squib ignition drive circuit) system52B-13
NOTE
(1) *: If the vehicle condition returns to normal, the diagnosis code will be automatically erased, and the SRS warning
lamp will return to normal.
(2) If the vehicle has a discharged battery it will store the fault codes 41 or 42. When these diagnosis codes are
displayed, check the battery.

SRS – Troubleshooting52B-7
INSPECTION PROCEDURE CLASSIFIED BY DIAGNOSIS CODE
Code No.14 Analog G-sensor system in the SRS-ECUProbable cause
The SRS-ECU monitors the output of the analog G-sensor inside the SRS-ECU.
It outputs this code when any of the following are detected.

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
Malfunction of SRS-ECU
Replace the SRS-ECU.
Code No.15, 16 Safing G-sensor system in the SRS-ECUProbable cause
This code is output if there is a short or open circuit between the terminals of the
safing G-sensor inside the SRS-ECU.
The trouble causes for each diagnosis code No. are as follows.
Malfunction of SRS-ECU
Code No.Trouble symptom
15Short circuit in the safing G-sensor
16Open circuit in the safing G-sensor
Replace the SRS-ECU.

SRS – Troubleshooting52B-8
Code No.21, 22, 61 or 62 Driver’s side air bag module
(squib) systemProbable cause
These diagnosis codes are output if there is abnormal resistance between the input
terminals of the driver’s side air bag module (squib).
The trouble causes for each diagnosis code No. are as follows.
Malfunction of clock spring

Partial disconnection due to incorrect clock spring
neutral position

Malfunction of wiring harnesses or connectors

Malfunction of driver’s side air bag module (squib)

Malfunction of SRS-ECU
Code No.Trouble symptom
21
Short in driver’s side air bag module (squib) or harness short

Short in clock spring

Malfunction of connector*
22
Open circuit in driver’s side air bag module (squib) or open harness

Open circuit in clock spring

Malfunction of connector contact
61
Short in driver’s side air bag module (squib) harness leading to the power supply
62
Short in driver’s side air bag module (squib) harness leading to the earth
NOTE
*: The connector in the squib circuit has a built-in short bar which short-circuits between plus (+) lead and minus
(–) lead of the squib circuit when the connector is not being connected to prevent an accidental air bag deployment
possibly caused by static electricity, etc. Therefore, malfunction of the connector can also be caused by this
short bar which fails to be released even when the connector is reconnected if it is damaged.
MUT-II Self-diag code

Disconnect clock spring
connector B-82.

Connect SRS check har-
ness connector (1).

Erase diagnosis code
memory.
Are code Nos.21, 22, 61 or
62 output?Ye sCheck the following
connectors:
B-82, B-51NG
Repair
OK
Check trouble symptoms.
NG
Check the harness wire
between the SRS-ECU
and clock spring.NG
Repair
OK
Replace the SRS-ECU.
No
Check the clock spring. (Refer to P.52B-30.)NG
Repair
OK
Replace the driver’s side air bag module.
SRS check harness
(MB991613)
Body wiring
harness
Clock spring
1

SRS – Troubleshooting52B-9
Code No.24, 25, 64 or 65 Front passenger’s side air bag
module (squib) systemProbable cause
These diagnosis codes are output if there is abnormal resistance between the input
terminals of the driver’s side air bag module (squib).
The trouble causes for each diagnosis code No. are as follows.
Malfunction of wiring harnesses or connectors

Malfunction of front passenger’s side air bag module
(squib)

Malfunction of SRS-ECU
Code No.Trouble symptom
24
Short in front passenger’s side air bag module (squib) or harness short

Malfunction of connector*
25
Open circuit in front passenger’s side air bag module (squib) or open harness

Malfunction of connector contact
64
Short in front passenger’s side air bag module (squib) harness leading to the power
supply
65
Short in front passenger’s side air bag module (squib) harness leading to the earth
NOTE
*: The connector in the squib circuit has a built-in short bar which short-circuits between plus (+) lead and minus
(–) lead of the squib circuit when the connector is not being connected to prevent an accidental air bag deployment
possibly caused by static electricity, etc. Therefore, malfunction of the connector can also be caused by this
short bar which fails to be released even when the connector is reconnected if it is damaged.
OK
Check trouble symptoms.
NG
Check the harness wire
between the front passen-
ger’s side air bag module
(squib) and SRS-ECU.NG
Repair
OK
Replace the SRS-ECU.
Ye sCheck the following
connectors:
B-01, B-51NG
RepairSRS check harness
(MB991613)
Body
wiring
harness
1
No
Replace the front passenger’s side air bag module.MUT-II Self-diag code

Disconnect front
passenger’s side air bag
module connector B-01.

Connect SRS check
harness connector (1).

Erase diagnosis code
memory.
Are code Nos.24, 25, 64 or 65
output?
Code No.31 or 32 SRS-ECU capacitor systemProbable cause
Probable cause
These diagnosis codes are output if there is abnormal resistance between the input
terminals of the driver’s side air bag module (squib).
Malfunction of SRS-ECU
Code No.Trouble symptom
31
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 diagnosis code No.41 or 42 indicating system voltage
drop has been output.)
Replace the SRS-ECU.

SRS – Troubleshooting52B-10
Code No.34 Connector lock systemProbable cause
This diagnosis code is output if a poor connection of the SRS-ECU is detected. However,
if the vehicle condition returns to normal, diagnosis code No.34 will be automatically
erased, and the SRS warning lamp will switch off.
Malfunction of connectors

Malfunction of SRS-ECU
Is B51 SRS-ECU connector correctly connected?Ye s
No
Repair
Check the following connector:
B-51
OK
Replace the SRS-ECU.ReplaceNG
Code No.35 SRS-ECU (deployed air bag) systemProbable cause
This diagnosis code is output after the air bag deploys. If this code is output before
the air bag has deployed, the cause is probably a malfunction inside the SRS-ECU.
Malfunction of SRS-ECU
Replace the SRS-ECU.
Code No.41 IG1 (A) power circuit systemProbable cause
This diagnosis code is output if the voltage between the IG1 (A) terminal and the
earth is lower than the specified value for a continuous period of 5 seconds or more.
However, if the vehicle condition returns to normal, diagnosis code No.41 will be
automatically erased, and the SRS warning lamp will switch off.
Malfunction of wiring harnesses or connectors

Malfunction of SRS-ECU
Measure at SRS check harness
connector (5).

Disconnect SRS-ECU
connector B-51.

Connect SRS check
harness connector (3).

Continuity between
terminals (20)
OK:ContinuityNGCheck the following
connectors:
B-51, B-78, B-80NG
Repair
OK
Check trouble symptoms.
NG
Check the harness wire between the SRS-ECU and earth, and
repair if necessary.
OK
Measure at SRS check harness connector (5).

Disconnect SRS-ECU connector B-51.

Connect SRS check harness connector (3).

Ignition switch: ON

Voltage between terminal (14) and body earth
OK:9 V or moreNGCheck the following
connectors:
B-51, B-78NG
Repair
OK
Check trouble symptoms.
NG
Check the harness wire between the SRS-ECU and ignition switch
IG
1, and repair if necessary.
OK
Replace the SRS-ECU.
SRS check harness
(MB991613)
3
5

SRS – Troubleshooting52B-11
Code No.42 IG1 (B) power circuit systemProbable cause
This diagnosis code is output if the voltage between the IG1 (B) terminal and the
earth is lower than the specified value for a continuous period of 5 seconds or more.
However, if the vehicle condition returns to normal, diagnosis code No.42 will be
automatically erased, and the SRS warning lamp will switch off.
Malfunction of wiring harnesses or connectors
NG
Check the harness wire between the SRS-ECU and ignition switch
IG
1, and repair if necessary.
OK
Check trouble symptoms.
OK
Replace the SRS-ECU.
OK
Measure at SRS check harness connector (5).

Disconnect SRS-ECU connector B-51.

Connect SRS check harness connector (3).

Ignition switch: ON

Voltage between terminal (13) and body earth
OK:9 V or moreNGCheck the following
connectors:
B-51, B-78NG
Repair
NG
Check the harness wire between the SRS-ECU and earth, and
repair if necessary.
OK
Check trouble symptoms.
Measure at SRS check harness
connector (5).

Disconnect SRS-ECU
connector B-51.

Connect SRS check
harness connector (3).

Continuity between
terminals (20)
OK:ContinuityNGCheck the following
connectors:
B-51, B-78, B-80NG
RepairSRS check harness
(MB991613)
3
5

SRS – Troubleshooting52B-12
Code No.43 SRS warning lamp drive circuit system
(Lamp does not illuminate.)Probable cause
This diagnosis code is output when an open circuit occurs for a continuous period
of 5 seconds while the SRS-ECU in monitoring the SRS warning lamp and the lamp
is OFF (transistor OFF).
However, if this code is output due to an open circuit, if the vehicle condition returns
to normal, this diagnosis code No.43 will be automatically erased, and the SRS warning
lamp will return to normal.
Malfunction of wiring harnesses or connectors

Blown bulb

Malfunction of SRS-ECU

Malfunction of combination meter
OK
Replace the combination
meter.
NG
Check the harness wire
between the SRS-ECU
and ignition switch (IG
1).NG
Repair
OK
Check trouble symptoms.
OK
Check the following
connectors:
B-51, B-09, B-08, B-75,
B-76NG
Repair
NG
Check the harness wire between the SRS-ECU and earth, and
repair if necessary.
OK
Check trouble symptoms.
Measure at SRS check harness
connector (5).

Disconnect SRS-ECU
connector B-51.

Connect SRS check
harness connector (3).

Continuity between
terminals (20)
OK:ContinuityNGCheck the following
connectors:
B-51, B-78, B-80NG
Repair
OK
Measure at SRS check harness connector (5).

Disconnect SRS-ECU connector B-51.

Connect SRS check harness connector (3).

Ignition switch: ON

Connect terminal (15) to the body earth.
OK:Lamp illuminatesNGBlown bulb inspectionNG
Repair
OK
Replace the SRS-ECU.
SRS check harness
(MB991613)
3
5
Code No.43 SRS warning lamp drive circuit system
(Lamp does not switch off.)
Probable cause
This diagnosis code is output when a short to earth occurs in the harness between
the lamp and the SRS-ECU while SRS-ECU is monitoring the SRS warning lamp
and the lamp is ON.
Malfunction of wiring harnesses or connectors

Malfunction of SRS-ECU

Malfunction of combination meter
SRS warning lamp inspection

Ignition switch: ON

Does lamp switch off when SRS-ECU connector B-51 is
disconnected?NoCheck the following
connectors:
B-51, B-09NG
Repair
Ye s
Replace the SRS-ECU.
OK
Check trouble symptoms.
NG
Check the harness wire
between the SRS-ECU
and combination meter,
and repair if necessary.

SRS – Troubleshooting52B-13
Code No.44 SRS warning lamp drive circuit systemProbable cause
This diagnosis code is output when a short occurs in the lamp drive circuit or a
malfunction of the output transistor inside the SRS-ECU is detected while the SRS-ECU
is monitoring the SRS warning lamp drive circuit.
Malfunction of wiring harnesses or connectors

Malfunction of SRS-ECU
Check the SRS warning lamp drive circuit system.
(Refer to P.52B-12)OKReplace the SRS-ECU.
Code No.45 SRS-ECU non-volatile memory (EEPROM)
and A/D converter systemProbable cause
This diagnosis code is output if there is a malfunction in the SRS-ECU non-volatile
memory (EEPROM) and A/D converter.
Malfunction of SRS-ECU
Code No.Trouble symptom
45Non-volatile memory
(EEPROM)
Non-volatile memory (EEPROM) is abnormal.
Replace the SRS-ECU.
Code No.51 or 52 Driver’s side air bag module (squib
ignition drive circuit) systemProbable cause
This diagnosis code is output if a short (No.51) or an open circuit (No.52) is detected
in the circuit for the driver’s seat.
Malfunction of SRS-ECU
Code No.Trouble symptom
51Driver’s side air bag module
(squib ignition drive circuit)

Short circuit in the squib ignition drive circuit
52
(squib ignition drive circuit)

Open circuit in the squib ignition drive circuit
Replace the SRS-ECU.
Code No.54 or 55 Front passenger’s side air bag module
(squib ignition drive circuit) systemProbable cause
This diagnosis code is output if a short (No.54) or an open circuit (No.55) is detected
in the circuit for the passenger’s seat.
Malfunction of SRS-ECU
Code No.Trouble symptom
54Front passenger’s side air
bag module (squib ignition

Short circuit in the squib ignition drive circuit
55
bag module (squib ignition
drive circuit)
Open circuit in the squib ignition drive circuit
Replace the SRS-ECU.

SRS – Troubleshooting52B-14
SRS WARNING LAMP INSPECTION
1. Check to be sure that the SRS warning lamp illuminates
when the ignition switch is in the ON position.
2. Check to be sure that it illuminates for approximately
7 seconds and then switches off.
3. If the above is not the cause, inspect the diagnosis codes.
INSPECTION CHART FOR TROUBLE SYMPTOMS
Get an understanding of the trouble symptoms and check according to the inspection procedure chart.
Trouble symptomInspection procedure No.Reference page
Communication with
MUT-II is not possible.Communication with all systems is not
possible.152B-14
Communication is not possible with
SRS only.252B-15
When the ignition key is turned to “ON” (engine stopped), the
SRS warning lamp does not illuminate.Refer to diagnosis code No.43.52B-12
After the ignition switch is turned to ON, the SRS warning lamp
is still on after approximately 7 seconds have passed.Refer to diagnosis code No.43.52B-12
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
Inspection Procedure 1
Communication with MUT-II is not possible. (Communica-
tion with all systems is not possible.)
Probable cause
The cause is probably a power supply system (including earth circuit) of the diagnosis
line.
Malfunction of connectors

Malfunction of wiring harness
Refer to GROUP 13A – Troubleshooting.
SRS warning lamp