Mitsubishi Colt Ralliart. Manual - part 572

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-126

DIAGNOSIS PROCEDURE

STEP 1. Check the side impact sensor (RH) 
(front). (M.U.T.-III diagnosis code)
(1) Disconnect the negative battery terminal.
(2) Temporarily replace the side impact sensor (RH) 

with the side impact sensor (LH).

(3) Connect the negative battery terminal.
(4) Erase diagnosis code memory, and check the 

diagnosis code.

Q: Is diagnosis code 79 or 93 out put?

YES : 

Replace the side impact sensor (RH) with a 

new one (Refer to 

P.52B-157

).

NO : 

Go to Step 2.

STEP 2. Check the harness wires for open circuit 
or short circuit between SRS-ECU connector 
B-34 (terminal No.40 and 42) and side impact 
sensor (RH) connector C-27 (terminal No.2 and 
1).

Q: Is the check result normal? 

YES : 

Go to Step 3.

NO : 

Repair the harness wires between 
SRS-ECU connector B-34 (terminal No.40 
and 42) and side impact sensor (RH) 
connector C-27 (terminal No.2 and 1).

STEP 3. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code 89 or 96 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

AG

B-34 (Y)

Connector: B-34

Harness side 
connector 
(rear view)

343536373839404142

252627282930313233

2122

2324

AC401057

AK

Connector: C-27

C-27 (Y)

Harness side
(front view)

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-127

 Code No.91: Side impact sensor (LH) voltage error

OPERATION

The side impact sensor includes an analogue G-sen-
sor and CPU, etc. The CPU monitors the analogue 
G-sensor output signal. If the CPU judges that the 
side-airbags should be deployed, it sends a fire sig-
nal to the SRS-ECU to deploy the side-airbags. 
Besides that, the CPU diagnoses the internal compo-
nents of the side impact sensor. If a malfunction 
occurs, it requests the SRS-ECU to set a diagnosis 
code.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code will set when the power supply 
voltage to the side impact sensor (LH) remains less 
than a predetermined value for 5 seconds. However, 
if the system returns to normal condition, code 
number 91 will be erased automatically and the SRS 
warning lamp will go out.

PROBABLE CAUSES

• Damaged wiring harness or connectors

• Malfunction of the side-airbag module (LH)

• Malfunction of the SRS-ECU

AC510253

SRS-ECU

CONSTANT
VOLTAGE CIRCUIT

ANALOGUE
G SENSOR

EEP ROM

SIDE IMPACT
SENSOR (LH)

MICRO COMPUTER 

INTERFACE 
CIRCUIT

CPU

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   

Side Impact Sensor (LH) Power Supply Circuit

AB

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-128

DIAGNOSIS PROCEDURE

STEP 1. Check the harness wires for open circuit 
or short circuit between SRS-ECU connector 
B-34 (terminal No.34 and 36) and side impact 
sensor (LH) connector C-21 (terminal No.1 and 
2).

Q: Is the check result normal?

YES : 

Go to Step 2.

NO : 

Repair the harness wires between 
SRS-ECU connector B-34 (terminal No.34 
and 36) and side impact sensor (LH) 
connector C-21 (terminal No.1 and 2).

STEP 2. Check the side impact sensor (LH) 
(front). (M.U.T.-III diagnosis code)
(1) Disconnect the negative battery terminal.
(2) Replace the side impact sensor (LH) (front) with 

the side impact sensor (RH) (front).

(3) Connect the negative battery terminal.
(4) Erase diagnosis code from memory, and check 

the diagnosis code.

Q: Is diagnosis code 91 set?

YES : 

Replace the SRS-ECU (Refer to 

P.52B-143

).

NO : 

Replace the side impact sensor (LH) (front) 
with a new one (Refer to 

P.52B-157

). Go to 

Step 3 .

STEP 3. Check whether the diagnosis code is 
reset.

Q: Is diagnosis code 91 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

).

Code No.92: G-sensor of side impact sensor (LH) failure 

 

Code No.95: G-sensor of side impact sensor (RH) failure

DIAGNOSIS CODE SET CONDITIONS

These diagnosis codes are set if the followings are 
detected from the analogue G-sensor inside the side 
impact sensor (front) output.

• Analogue G-sensor inside the side impact sensor 

is not operating.

• Analogue G-sensor inside the side impact sensor 

characteristics are abnormal.

• Analogue G-sensor inside the side impact sensor 

output is abnormal.

PROBABLE CAUSE

Malfunction of side impact sensor (LH) (for diagnosis 
code 92) and side impact sensor (RH) (for diagnosis 
code 95)

DIAGNOSIS PROCEDURE

Replace side impact sensor (LH) (for diagnosis code 
92) and side impact sensor (RH) (for diagnosis code 
95). (Refer to 

P.52B-157

).

AC206285

AG

B-34 (Y)

Connector: B-34

Harness side 
connector 
(rear view)

343536373839404142

252627282930313233

2122

2324

AC401059

Connector: C-21

AF

C-21 (Y)

Harness side
(front view)

Main

Index

Group

TOC

TROUBLESHOOTING

SUPPLEMENTAL RESTRAINT SYSTEM (SRS)

52B-129

Code No.94: Side impact sensor (RH) voltage error

OPERATION

The side impact sensor includes an analogue G-sen-
sor and CPU, etc. The CPU monitors the analogue 
G-sensor output signal. If the CPU judges that the 
side-airbags should be deployed, it sends a fire sig-
nal to the SRS-ECU to deploy the side-airbags. 
Besides that, the CPU diagnoses the internal compo-
nents of the side impact sensor. If a malfunction 
occurs, it requests the SRS-ECU to set a diagnosis 
code.

DIAGNOSIS CODE SET CONDITIONS

This diagnosis code is set if the power supply voltage 
of the side impact sensor (RH) drops below the rated 
value for a continuous period of 5 seconds or more. 
However, if the system returns to normal condition, 
code number 94 will be erased automatically and the 
SRS warning lamp will go out. 

PROBABLE CAUSES

• Damaged wiring harnesses or connectors

• Malfunction of the side-airbag module (RH)

• Malfunction of the SRS-ECU

AC510252

MICRO COMPUTER

INTERFACE 
CIRCUIT

CPU

SRS-ECU

ANALOGUE
G SENSOR

EEP ROM

SIDE IMPACT
SENSOR (RH)

CONSTANT
VOLTAGE CIRCUIT

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   

Side Impact Sensor (RH) Circuit

AB

Main

Index

Group

TOC