Mitsubishi Montero (2002-2004). Manual - part 786

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DIAGNOSIS

52Bb-13

STEP 6. Recheck the diagnostic trouble code. 
Q: Is any of DTC 11, 12 or 13 set?

YES : Return to Step 1. 
NO :  The procedure is complete. (If no malfunctions are not 

found in all steps, an intermittent malfunction is 
suspected. Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points 

− How to 

Cope with Intermittent Malfunction 

P.00-6

.)

DTC 14: Analog G-Sensor System in the SRS-ECU
DTC 15: Safing G-Sensor Short Circuit
DTC 16: Safing G-Sensor Open Circuit
DTC 17: Safing G-Sensor for Side-AirBag Faults
DTC 31: SRS-ECU Capacitor Circuit Voltage too High
DTC 32: SRS-ECU Capacitor Circuit Voltage too Low
DTC 45: SRS-ECU Non-Volatile Memory (EEPROM) and A/D Converter System
DTC 51: Driver's Air Bag Module (Squib Ignition Drive Circuit) System Detected Short Circuit
DTC 52: Driver's Air Bag Module (Squib Ignition Drive Circuit) System Detected Open Circuit
DTC 54: Passenger’s (Front) Air Bag Module (Squib Ignition Drive Circuit) System Detected Short 
Circuit
DTC 55: Passenger’s (Front) Air Bag Module (Squib Ignition Drive Circuit) System Detected Open 
Circuit
DTC 56: Driver’s Seat Belt Pre-tensioner (Squib Ignition Drive Circuit) System Detected Short Circuit
DTC 57: Driver’s Seat Belt Pre-tensioner (Squib Ignition Drive Circuit) System Detected Open Circuit
DTC 58: Passenger’s Seat Belt Pre-tensioner (Squib Ignition Drive Circuit) System Detected Short 
Circuit
DTC 59: Passenger’s Seat Belt Pre-tensioner (Squib Ignition Drive Circuit) System Detected Open 
Circuit
DTC 73: Right Hand Side-Airbag Module (Squib) System Detected Short Circuit
DTC 74: Right Hand Side-Airbag Module (Squib) System Detected Open Circuit
DTC 83: Left Hand Side-Airbag Module (Squib) System Fault 3 for Ignition Drive Circuit
DTC 84: Left Hand Side-Air Bag Module (Squib) System Fault 4 for Ignition Drive Circuit

.

DTC SET CONDITIONS
These DTC are set when a fault is detected in the 
SRS-ECU. The most likely causes for this code to be 
set are shown in the table below:

CODE NO.

DEFECTIVE PART

SYMPTOMS

14

Analog G-sensor

• When the analog G-sensor is not operating

• When the characteristics of the analog G-sensor are 

abnormal

• When the output from the analog G-sensor is 

abnormal

15

Safing G-sensor (front air bag)

• Short circuit in the safing G-sensor

16

• Open circuit in the safing G-sensor

17

Safing G-sensor (side-airbag)

• When the safing G-sensor is not operating

• When the characteristics of the safing G-sensor are 

abnormal

• When the output from the safing G-sensor is abnormal

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DIAGNOSIS

52Bb-14

.

TROUBLESHOOTING HINTS
Malfunction of the SRS-ECU

.

DIAGNOSIS

Required Special Tools:

• MB991502: Scan Tool (MUT-II)

Replace the SRS-ECU. (Refer to 

P.52Ba-31

.) 

Check the diagnosis trouble code.
Q: Is any of DTC set?

YES : There is no action to be taken.
NO :  The procedure is complete.

31

Capacitor

• Voltage at the capacitor terminal is higher than the 

specified value for five seconds or more

32

• Voltage at the capacitor terminal is lower than the 

specified value for five seconds or more (This is not 
detected if DTC No. 41 or 42 indicating battery 
positive voltage drop has been output.)

45

Non-volatile memory (EEPROM) 
and A/D converter

• When the non-volatile memory (EEPROM) and A/D 

converter system are abnormal

51

Driver's air bag module (squib 
ignition drive circuit)

• Short circuit in the squib ignition drive circuit

52

• Open circuit in the squib ignition drive circuit

54

Front passenger's air bag module 
(squib ignition drive circuit)

• Short circuit in the squib ignition drive circuit

55

• Open circuit in the squib ignition drive circuit

56

Driver’s seat belt pre-tensioner 
(squib ignition drive circuit)

• Short circuit in the squib ignition drive circuit

57

• Open circuit in the squib ignition drive circuit

58

Passenger’s seat belt pre-
tensioner (squib ignition drive 
circuit)

• Short circuit in the squib ignition drive circuit

59

• Open circuit in the squib ignition drive circuit

73

Side-airbag module (RH) (squib 
ignition drive circuit)

• Short circuit in the squib ignition drive circuit

74

• Open circuit in the squib ignition drive circuit

83

Side-airbag module (LH) (squib 
ignition drive circuit)

• Short circuit in the squib ignition drive circuit

84

• Open circuit in the squib ignition drive circuit

CODE NO.

DEFECTIVE PART

SYMPTOMS

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DIAGNOSIS

52Bb-15

DTC 21: Driver’s Air Bag Module (Squib) System Fault 1 (Short Circuit between Terminals of the Squib 
Circuit)

.

AC204430

Driver's Air Bag Module (Squib) Circuit 

NOTE

: CONNECTOR LOCK SWITCH

CONNECTOR

CONNECTED: ON
CONNECTOR

DISCONNECTED: OFF

AB

AC204226AD

CLOCK SPRING

D-206 (Y)

CONNECTORS: D-206, D-229

D-229

ACX01478 AG

CONNECTOR: E-08

E-08 (Y)

SRS AIR BAG DIAGNOSIS

TSB Revision

SUPPLEMENTAL RESTRAINT SYSTEM (SRS) DIAGNOSIS

52Bb-16

CIRCUIT OPERATION

• The SRS-ECU judges how severe a collision is 

by detecting signals from the front impact sensors 
and the front air bag analog G-sensor. If the 
impact is over a predetermined level, the SRS-
ECU outputs an ignition signal. At this time, if the 
front air bag safing G-sensor is on, the SRS air 
bag will inflate. 

• The ignition signal is input to the air bag module 

via the clock spring to inflate the air bag.

.

DTC SET CONDITIONS
This DTC is set if there is abnormal resistance 

between the input terminals of the driver's side air 
bag module (squib). The most likely causes for 
this code to be set the followings: 

• Short circuit in driver’s air bag module (squib) 

or harness

• Short circuit in the clock spring

However, if no DTC resets, the SRS warning light will 
be switched off (DTC will be retained). 

.

TROUBLESHOOTING HINTS

• Improper engaged connector or defective short 

bar*

• Short circuit in the clock spring

• Short circuit between the driver's air bag module 

(squib) circuit terminals

• Damaged connector(s)

• Malfunction of the SRS-ECU

.

NOTE: *: The squib circuit connectors integrate a 
"short" bar (which prevents the air bag from deploy-
ing unintentionally due to static electricity by shorting 
the positive wire to the ground wire in the squib cir-
cuit when the connectors are disconnected). (Refer 
to 

P.52Bb-2

.) Therefore, if connector E-08, D-206 or 

D-229 is damaged or improperly engaged, the short 
bar may not be released when the connector is con-
nected. 

.

DIAGNOSIS

Required Special Tools:

• MB991502: Scan Tool (MUT-II)

• MB991865: Dummy resister

• MB991866: Resister harness

STEP 1. Check the diagnostic trouble code.
Q: Is DTC 34 set?

YES : Go to Step 2.
NO :  Go to Step 3.

STEP 2. Check SRS-ECU connector E-08.
Q: Is the connector correctly engaged?

YES : Go to Step 3.
NO :  Engage the connector correctly. Then go to Step 8.

ACX01478 AG

CONNECTOR: E-08

E-08 (Y)