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Mitsubishi Colt Ralliart. Manual - part 559

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-74

STEP 6. Resistance measurement at the
SRS-ECU connector B-35

(1) Disconnect SRS-ECU connector B-35, 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) Resistance measurement between terminal 16

and body earth.

OK: Open circuit

Q: Is the check result normal?

YES : .

Go to Step 7.

NO : .

Check the harness wire for short circuit

between SRS-ECU connector B-35
(terminal No.16) and junction block
connector B-131 (terminal No.31), and
repair if necessary.

STEP 7. Check whether the diagnosis code is
reset.

Q: Is diagnosis code 41 set?

YES :

Replace the SRS-ECU (Refer to

P.52B-143

NO :

An intermittent malfunction is suspected
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction

P.00-13

AC206285

B-35 (Y)

Connector: B-35

Harness side
connector
(rear view)

AC201665

13 14 15 16 17 18 19 20

5 6 7 8 9 10 11 12

1 2

3 4

B-35 Harness side connector
(rear view)

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-75

Code No.42: Power supply voltage (IG1 (B) voltage) drops abnormally.

OPERATION

• The SRS-ECU is powered from the ignition

switch (IG1).

• The SRS-ECU power is supplied from two cir-

cuits. Even if one circuit is shut off, the air bag
can inflate.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if the voltage between the
IG1 terminals (fuse No.37 circuit) and earth is lower
than a predetermined value for a continuous period
of 5 second or more. However, if the system returns
to normal condition, code number 42 will be erased
automatically and the SRS warning lamp will go out.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Check junction block fuse number 37.

Q: Is the fuse burned out?

YES :

Go to Step 4.

NO :

Go to Step 2.

AC510234

Wire colour code
B : Black LG : Light green G : Green L : Blue W : White Y : Yellow SB : Sky blue
BR : Brown O : Orange GR : Grey R : Red P : Pink V : Violet

IGNITION
SWITCH (IG1)

SRS-ECU

IG1 Power Supply Circuit System

AC207473

Junction
block

Fuse No.37

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-76

STEP 2. Voltage measurement at SRS-ECU
connector B-35.
(1) Disconnect the negative battery terminal.

(2) Disconnect SRS-ECU connector B-35.
(3) Connect the negative battery terminal.
(4) 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.
(5) Voltage measurement between B-35 harness

side connector terminal 13 and body earth.

OK: 9 V or more

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Go to Step 3.

STEP 3. Connector check: SRS-ECU connector
B-35 and ignition switch connector B-141,
junction block connector B-129 and B-131.

Q: Is the check result normal?

YES :

Check the harness wires for open or short

circuit between SRS-ECU connector B-35
(terminal No.13) and ignition switch
connector B-141 (terminal No.2), and repair
if necessary.

NO :

Repair or replace it.

AC206285

B-35 (Y)

Connector: B-35

Harness side
connector
(rear view)

13 14 15 16 17 18 19 20

5 6 7 8 9 10 11 12

1 2

3 4

AC301016 AD

B-35 Harness side
connector (rear view)

AC206285

B-35 (Y)

Connector: B-35

Harness side
connector
(rear view)

AC313828 AG

Connector: B-141

Harness side
connector
(front view)

Clock spring

AC313827AH

B-131

B-129

Connectors: B-129, B-131

Junction block (Rear view)

Harness side

B-129

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-77

STEP 4. Check a burned-out fuse.
(1) Replace the fuse.
(2) Turn the ignition switch to the "ON" position, wait

for at least one minute and then turn the ignition
switch to the "LOCK" (OFF) position.

(3) Check the fuse.

Q: Is the fuse in good condition?

YES :

Go to Step 7.

NO :

Go to Step 5.

STEP 5. Resistance measurement at the junction
block connector B-131

(1) Disconnect junction block connector B-131, 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) Resistance measurement between terminal 13

and body earth.

OK: Open circuit

Q: Is the check result normal?

YES :

Check the other circuit, which flows through

fuse number 37.

NO :

Go to Step 6.

STEP 6. Resistance measurement at the
SRS-ECU connector B-35.

(1) Disconnect SRS-ECU connector B-35 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) Resistance measurement between terminal 13

and body earth.

OK: Open circuit

Q: Is the check result normal?

YES :

Go to Step 7.

NO :

Check the harness wire for short circuit
between SRS-ECU connector B-35
(terminal No.13) and junction block
connector B-131 (terminal No.13), and
repair if necessary.

STEP 7. Check whether the diagnosis code is
reset.

Q: Is diagnosis code 42 set?

YES :

Replace the SRS-ECU (Refer to

P.52B-143

NO :

An intermittent malfunction is suspected
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction

P.00-13

AC313826

Connector: B-131

Junction Block (Rear view)

Harness side

AC208769

B-35 Harness side connector (rear view)

AC206285

B-35 (Y)

Connector: B-35

Harness side
connector
(rear view)

AC202026

13 14 15 16 17 18 19 20

5 6 7 8 9 10 11 12

1 2

3 4

B-35 Harness side connector
(rear view)

Main

Index

Group

TOC

Content .. 557 558 559 560 ..