Mitsubishi Grandis. Manual — part 1034

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-188

Code No.B1508: Seat Slide Sensor System Fault Power Supply Circuit (Short-Circuited to Power
Supply)

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

SRS-ECU

SEAT SLIDE
SENSOR

Seat Slide Sensor Circuit <LH drive vehicles>

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-189

CAUTION

If diagnosis code B1508 is set in the SRS-ECU,
always diagnose the CAN bus lines.

OPERATION

• The seat slide sensor sets the current value Hi or

Low determined by the seat position.

• The SRS-ECU determines the seat position

according to the current value from the seat slide
sensor.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if there is abnormal
resistance between the input terminals of the seat
slide sensor.

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Short to the power supply in the seat slide sensor

harness

• Malfunction of the SRS-ECU

DIAGNOSIS PROCEDURE

STEP 1. MUT-III CAN bus diagnostics
Use the MUT-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the CAN bus line (Refer to GROUP
54D, Diagnosis

P.54D-16

).

STEP 2. Check whether the diagnosis code is
reset.
Check again if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition: LOCK (OFF) position to ON
(3) On completion, check that the diagnosis code is

not reset.

Q: Is the diagnosis code set?

YES :

Go to Step 3.

NO :

There is an intermittent malfunction such as
poor engaged connector(s) or open circuit
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction

P.00-5

).

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

SRS-ECU

SEAT SLIDE
SENSOR

Seat Slide Sensor Circuit <RH drive vehicles>

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-190

STEP 3. Check the seat slide sensor. (MUT-III
diagnosis code.)
(1) Disconnect the negative battery terminal.

(2) Disconnect the seat slide sensor connector D-21

<LHD> or D-33 <RHD>.

(3) Connect special tool dummy resistor (MB991865)

to special tool resistor harness (MB991866).

CAUTION

Do not insert a test probe into the terminal from
its front side directly, as the connector contact
pressure may be weakened.
(4) Insert special tool MB991866 into the D-21

<LHD> or D-33 <RHD> harness side connector
by backprobing.

(5) Connect the negative battery terminal.
(6) Erase the diagnosis code memory, and check the

diagnosis code.

Q: Is diagnosis code B1508 set?

YES :

Go to Step 4.

NO :

Replace the seat slide sensor. (Refer to

P.52B-242

). Then go to Step 6.

STEP 4. Check the seat slide sensor circuit at the
SRS-ECU connector C-120.
(1) Disconnect SRS-ECU connector C-120.

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 C-120 harness side

connector terminals 1, 2 and body earth.

OK: Open circuit

Q: Is the check result normal?

YES :

Erase the diagnosis code memory, and

check the diagnosis code. If diagnosis code
B1508 sets, replace the SRS-ECU (Refer to

P.52B-223

). Then go to Step 6.

NO :

Go to Step 5.

STEP 5. Check the harness wires for short circuit
to earth between SRS-ECU connector C-120
(terminal No.1 and 2) and seat slide sensor
connector D-21 <LHD> or D-33 <RHD> (terminal
No.1 and 2).

Q: Are the harness wires between SRS-ECU

connector C-120 (terminal No.1 and 2) and seat
slide sensor connector D-21 <LHD> or D-33 <RHD>
(terminal No.1 and 2) in good condition?
YES :

Go to Step 6.

NO :

Repair the harness wires between
SRS-ECU connector C-120 and seat slide
sensor connector D-21 <LHD> or D-33
<RHD>. Then go to Step 6.

STEP 6. Check whether the diagnosis code is
reset.

Q: Is diagnosis code B1508 set?

YES :

Return to Step 1.

NO :

The procedure is complete.

AC310633

Harness side
connector
(rear view)

Connector: D-21 <LHD>

D-21(GR)

AG

AC310205

Harness side
connector
(rear view)

Connector: D-33 <RHD>

D-33(GR)

AG

AC006042CB

MB991866
(Resistor harness)

D-21<LHD> or
D-33<RHD> Harness
side connector

D-21<LHD> or
D-33<RHD> Seat slide
sensor connector

MB991865 (Dummy
resistor: 3

Ω)

(rear view)

AC308188

A

B

18

10

15

7

13

5

14

6

16

8

17

9

19

11

20

12

1 2

3 4

C-120 Harness side
connector (rear view)

AD

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-191

Code No.B1509: Improper installation of SRS-ECU

CAUTION

If diagnosis code B1509 is set in the SRS-ECU,
always diagnose the CAN main bus line.

DIAGNOSIS CODE SET CONDITIONS

This code is set when the vehicle specification does
not meet the ECU specification.

PROBABLE CAUSES

• Malfunction of the SRS-ECU

• Mismatch between vehicle and SRS-ECU

specifications

DIAGNOSIS PROCEDURE

STEP 1. MUT-III CAN bus diagnostics
Use the MUT-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the CAN bus line (Refer to GROUP
54D, Diagnosis

P.54D-16

).

STEP 2. Check whether the diagnosis code is
reset.
Check again if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition: LOCK (OFF) position to ON
(3) On completion, check that the diagnosis code is

not reset.

Q: Is the diagnosis code B1509 set?

YES :

Replace the SRS-ECU (Refer to

P.52B-223

).

NO :

There is an intermittent malfunction such as
poor engaged connector(s) or open circuit
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction

P.00-5

).

Code No. B1519: Connector Lock System Detects Connector Unlocked

CAUTION

If diagnosis code B1519 is set in the SRS-ECU,
always diagnose the CAN main bus line.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if a poor connection at the
SRS-ECU is detected. However, if the vehicle
condition returns to normal, diagnosis code number
B1519 will be automatically erased, and the SRS
warning lamp will go out.

PROBABLE CAUSES

• Damaged connectors

• Malfunction of the SRS-ECU

DIAGNOSIS

STEP 1. MUT-III CAN bus diagnostics
Use the MUT-III to diagnose the CAN bus lines.

Q: Is the check result normal?

YES :

Go to Step 2.

NO :

Repair the CAN bus line (Refer to GROUP
54D, Diagnosis

P.54D-16

).

STEP 2. Check whether the diagnosis code is
reset.
Check again if the diagnosis code is set.
(1) Erase the diagnosis code.
(2) Ignition: LOCK (OFF) position to ON
(3) On completion, check that the diagnosis code is

not reset.

Q: Is the diagnosis code set?

YES :

Go to Step 3.

NO :

There is an intermittent malfunction such as
poor engaged connector(s) or open circuit
(Refer to GROUP 00, How to Cope with
Intermittent Malfunction

P.00-5

).