Mitsubishi L200. Manual - part 595

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-51

STEP 3. Connector check: SRS-ECU connector 
C-131, junction block connector C-207 and C-208. 

AC501670

AB

C-131 (Y)

Connector: C-131

Harness side 
connector 
(rear view)

AC509934

Connectors: C-207, C-208 <LHD>

Junction block (Front view)

C-207

C-208

C-208

C-207

AB

Harness side

Harness side

AC509936

Connectors: C-207, C-208 <RHD>

C-207

C-208

C-207

Harness side

Harness side

C-208

AB

Junction block 
(Front view)

Q: Is the check result normal?

YES : 

Check the harness wires for open or short 

circuit between SRS-ECU connector C-131 
(terminal No.16) and ignition switch, and 
repair if necessary.

NO : 

Replace it.

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 : 

This diagnosis is complete.

NO : 

Go to Step 5.

STEP 5. Resistance measurement at the junction 
block connector C-208.

AC501670

AB

C-131 (Y)

Connector: C-131

Harness side 
connector 
(rear view)

(1) Disconnect SRS-ECU connector C-131.

AC509934

Connectors: C-208 <LHD>

Junction block (Front view)

C-208

AE

Harness side

AC509936

Connector: C-208 <RHD>

Harness side

C-208

AD

Junction block 
(Front view)

(2) Disconnect junction block connector C-208, and 

measure at the wiring harness side.

AC501390AB

C-208 Harness side connector (rear view)

CAUTION

Do not insert a test probe into the terminal from 
its front side directly as the connector contact 
pressure may be weakened.
(3) Resistance measurement between terminal 5 

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-52

and body earth.

OK: Open circuit

Q: Is the check result normal?

YES : 

Check the other circuit which flows through 

fuse number 15.

NO : 

Repair the wiring harness between junction 
block connector C-208 (terminal No.5) and 
SRS-ECU connector C-131 (terminal 
No.16), and replace the fuse.

STEP 6. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code B1476 set?

YES : 

Replace the SRS-ECU (Refer to 

P.52B-

266

). 

NO : 

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

Code No.B1477: Power supply voltage (IG1 (B) voltage) drops abnormally.

IG1 Power Supply Circuit System

IGNITION
SWITCH (IG1)

SRS-ECU

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     PU : Purple

OPERATION

• The SRS-ECU is powered from the ignition 

switch (ACC).

• 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.21 circuit) and earth is lower 
than a predetermined value for a continuous period 
of 5 seconds or more.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Malfunction of the SRS-ECU

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-53

DIAGNOSIS PROCEDURE

STEP 1. Check junction block fuse number 21.

AC509744

AD

Fuse No.21

Junction 
block

<LHD>

AC

AC502795

AD

Fuse No.21

Junction 
block

<RHD>

Q: Is the fuse burned out?

YES : 

Go to Step 4.

NO : 

Go to Step 2.

STEP 2. Voltage measurement at SRS-ECU 
connector C-131.
(1) Disconnect the negative battery terminal.

AC501670

AB

C-131 (Y)

Connector: C-131

Harness side 
connector 
(rear view)

(2) Disconnect SRS-ECU connector C-131.
(3) Connect the negative battery terminal.
(4) Turn the ignition switch to the "ON" position.

13 14 15 16 17 18 19 20

5 6 7 8 9 10 11 12

1 2

3 4

AC301016 AE

C-131 Harness side
connector (rear view)

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 C-131 harness 

side connector terminal 13 and body earth.

OK: 9 V or more

Q: Is the check result normal?

YES : 

Go to Step 6.

NO : 

Go to Step 3.

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-54

STEP 3. Connector check: SRS-ECU connector 
C-131, junction block connector C-207 and C-208.

AC501670

AB

C-131 (Y)

Connector: C-131

Harness side 
connector 
(rear view)

AC509934

Connectors: C-207, C-208 <LHD>

Junction block (Front view)

C-207

C-208

C-208

C-207

AB

Harness side

Harness side

AC509936

Connectors: C-207, C-208 <RHD>

C-207

C-208

C-207

Harness side

Harness side

C-208

AB

Junction block 
(Front view)

Q: Is the check result normal?

YES : 

Check the harness wires for open or short 

circuit between SRS-ECU connector C-131 
(terminal No.13) and ignition switch, and 
repair if necessary.

NO : 

Replace it.

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 : 

This diagnosis is complete.

NO : 

Go to Step 5.

STEP 5. Resistance measurement at the junction 
block connector C-208

AC501670

AB

C-131 (Y)

Connector: C-131

Harness side 
connector 
(rear view)

(1) Disconnect SRS-ECU connector C-131.

AC509934

Connectors: C-208 <LHD>

Junction block (Front view)

C-208

AE

Harness side

AC509936

Connector: C-208 <RHD>

Harness side

C-208

AD

Junction block 
(Front view)

(2) Disconnect junction block connector C-208, and 

measure at the wiring harness side.

AC501390AC

C-208 Harness side connector (rear view)

CAUTION

Do not insert a test probe into the terminal from 
its front side directly as the connector contact 
pressure may be weakened.
(3) Resistance measurement between terminal 8