Mitsubishi Grandis. Manual - part 1033

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-184

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 B1506 set?

YES : 

Go to Step 4.

NO : 

Replace the seat slide sensor. (Refer to 

P.52B-242

). Then go to Step 5.

STEP 4. Check the harness between the 
SRS-ECU connector C-120 (terminal No.1 and 2) 
and the seat slide sensor connector D-21 <LHD> 
or D-33 <RHD> (terminal No.1 and 2) for open 
circuit.
(1) Disconnect SRS-ECU connector C-120 and seat 

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

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 the following 

terminals. 

• SRS-ECU connector C-120 (terminal No.1) 

and the seat slide sensor connector D-21 
<LHD> or D-33 <RHD> (terminal No.1)

• SRS-ECU connector C-120 (terminal No.2) 

and the seat slide sensor connector D-21 
<LHD> or D-33 <RHD> (terminal No.2)

OK: Less than 2 

Ω

Q: Are the check results normal? 

YES : 

Erase the diagnosis code memory, and 

check the diagnosis code. If diagnosis code 
B1506 sets, replace the SRS-ECU (Refer to 

P.52B-223

). Then go to Step 5. 

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 5.

STEP 5. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code B1506 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)

AC308186

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)

D-21 or D-33 Harness side
connector (rear view)

AD

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-185

Code No.B1507: Seat Slide Sensor System Fault Earth Circuit (Short-Circuited to Earth)

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>

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-186

CAUTION

If diagnosis code B1507 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 earth 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

).

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 -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 B1507 set?

YES : 

Go to Step 4.

NO : 

Replace the seat slide sensor. (Refer to 

P.52B-242

). Then go to Step 6.

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)

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-187

STEP 4. Check the seat slide sensor circuit at the 
SRS-ECU connector C-120.
(1) Disconnect SRS-ECU connector C-120.
(2) 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.
(3) Measure the voltage between C-120 harness 

side connector terminals 1 and 2 and body earth.

OK: 0 V

Q: Is the check result normal?

YES : 

Erase the diagnosis code memory, and 

check the diagnosis code. If diagnosis code 
B1507 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 power supply 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 -21 <LHD> or D-33 
<RHD>. Then go to Step 6.

STEP 6. Check whether the diagnosis code is 
reset. 

Q: Is diagnosis code B1507 set?

YES : 

Return to Step 1. 

NO : 

The procedure is complete.

AC308187

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