Mitsubishi Lancer Evolution IX. Manual — part 646

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-97

COMMENTS ON TROUBLE SYMPTOM

If communication is not possible with the SRS only,
the cause is probably an open circuit in the on-board
diagnostic output circuit of the SRS or in the power
circuit (including earth circuit).

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Malfunction of the SRS-ECU

• Incorrect M.U.T.-II ROM pack

DIAGNOSIS PROCEDURE

STEP 1. Check that the M.U.T.-II/III can
communicate with the other systems.

Q: Can the M.U.T.-II/III communicate with the other

systems?
YES :

Go to Step 2.

NO :

Refer to GROUP 13A

− Troubleshooting

P.13A-237

.

STEP 2. Resistance measurement between
SRS-ECU connector C-12 (terminal No.20) and
diagnosis connector C-14 (terminal No.7)

(1) Disconnect SRS-ECU connector C-12 and

diagnosis connector C-14, and measure at the
wiring harness side.

AC101950AJ

SRS-ECU

Harness side
connector
(rear view)

C-12 (Y)

Connector: C-12

AC303800

Connector: C-14
<LHD>

AJ

Front side

C-14 (B)

AC303812

Connector: C-14
<RHD>

AE

Front side

C-14(B)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-98

CAUTION

Do not insert a test probe into the terminal from
of the SRS-ECU connector C-12 its front side
directly as the connector contact pressure may
be weakened.
(2) Resistance measurement between the following

terminals.

• SRS-ECU connector C-12 (terminal No.20)

and diagnosis connector C-14 (terminal No.7)

OK: Less than 2

Ω

Q: Is the check results normal?

YES :

Go to Step 3.

NO :

Go to Step 5.

STEP 3. Resistance measurement the earth
circuit to the SRS-ECU connector C-12

(1) Disconnect SRS-ECU connector C-12 and

measure at the wiring harness side.

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.
(2) Check for continuity between terminal 7 and body

earth.

OK: Less than 2

Ω

Q: Is the check result normal?

YES :

Go to Step 4.

NO :

Check the harness wire for open circuit
between SRS-ECU connector C-12
(terminal No.7) and earth, and repair if
necessary.

131415 1617 1819 20

5 6 7 8 9 10 1112

1 2

3 4

1 2 3 4 5 6 7 8
9 10 11121314 15 16

AC201667AN

C-12 Harness side
connector
(rear view)

C-14 Diagnosis
connector

AC101950AJ

SRS-ECU

Harness side
connector
(rear view)

C-12 (Y)

Connector: C-12

AC006264

13 14 15 16 17 18 19 20

5 6 7 8 9 10 11 12

1 2

3 4

AM

C-12 Harness side
connector (rear view)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-99

STEP 4. Voltage measurement the power supply
circuit to the SRS-ECU connector C-12

(1) Disconnect SRS-ECU connector C-12 and

measure at the wiring harness side.

(2) Connect the negative battery terminal.
(3) Turn the ignition switch to the "ON" position.

CAUTION

Do not insert a test probe into the terminal from
its front side directly as the connector contact
pressure may be weakened.
(4) Voltage measurement between terminals 13, 16

and body earth.

OK: 9 V or more

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Go to Step 6.

STEP 5. Check the harness wires between
SRS-ECU connector C-12 and diagnosis
connector C-14.

AC101950AJ

SRS-ECU

Harness side
connector
(rear view)

C-12 (Y)

Connector: C-12

AC006265

13 14 15 16 17 18 19 20

5 6 7 8 9 10 11 12

1 2

3 4

AR

C-12 Harness side
connector (rear view)

AC101950AJ

SRS-ECU

Harness side
connector
(rear view)

C-12 (Y)

Connector: C-12

AC303800

Connector: C-14
<LHD>

AJ

Front side

C-14 (B)

AC303812

Connector: C-14
<RHD>

AE

Front side

C-14(B)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-100

NOTE:

Prior to the wiring harness inspection, check junction
block connector C-101 <LHD> or C-23 <RHD>, and
repair if necessary.

Q: Is the check result normal?

YES :

An intermittent malfunction is suspected

(Refer to GROUP 00

− How to Use

Troubleshooting/Inspection Service Points

P.00-5

).

NO :

Repair the harness wires.

STEP 6. Check the harness wires between
SRS-ECU connector C-12 and ignition switch
connector C-208.

AC303798

Connector: C-101
<LHD>

BA

2

1

3

13

12

14

21

10

5

4

6

16

15

17

7 8 9

19

18

20

11

22

C-101 (L)

AC303814

Connector: C-23
<RHD>

AW

C-23 (B)

AC101950AJ

SRS-ECU

Harness side
connector
(rear view)

C-12 (Y)

Connector: C-12

AC303806

Connector: C-208
<LHD>

Harness side
connector
(front view)

AI

Clock spring

AC303820 AE

Connector: C-208
<RHD>

Harness side
connector
(front view)

Clock spring