[52B] SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - - SYSTEM OPERATION - SRS-ECU | PRINT PAGE / INDEX / PRIOR / NEXT

SRS-ECU The SRS-ECU incorporates an analogue G sensor and safing G sensor for frontal collisions. In frontal collisions, the driver's and front passenger's air bags deploy only when both the analogue and safing G sensors detect simultaneously a collision-induced G of a level exceeding the threshold as in the case with the conventional system. The SRS-ECU incorporates the impact detection door unlock signal process circuit. The SRS-ECU is provided with the following capabilities: Backup power supply in case of power failure in collisions: Back up capacitor Boosting function in case of battery voltage drop: DC - DC converter Self-diagnosis function to avoid system's operation errors and improve its reliability CAUTION Never disassemble the SRS-ECU.
DIAGNOSIS FUNCTION The SRS-ECU has the following functions to make system checking using MUT-II/III easy. Diagnosis code output Service data output
DIAGNOSIS CODE OUTPUT The SRS-ECU diagnoses the following items and stores a diagnosis code in the non-volatile memory (EEPROM*1) when a problem is detected. Therefore, the memory is not deleted after a battery terminal is disconnected. (The diagnosis code memory can be deleted by the MUT-II/III.)
CODE NO. | MAJOR CONTENTS OF DIAGNOSTICS
--- | ---
1A*4 | Front impact sensor LH system | Short circuit in the sensor
1B*4 | Open circuit in the sensor
1C*4 | Short circuit in the power supply
1D*4 | Short circuit in the earth
2A*4 | Front impact sensor RH system | Short circuit in the sensor
2B*4 | Open circuit in the sensor
2C*4 | Short circuit in the power supply
2D*4 | Short circuit in the earth
11*5 | Front impact sensor short-circuited
12*5 | One front impact sensor open-circuited
13*5 | Two front impact sensor open-circuited
14 | Analogue G-sensor malfunction
15 | Safing G-sensor short-circuited (for frontal collision)
16 | Safing G-sensor open-circuited (for frontal collision)
17 | Safing G-sensor malfunction (for side collision)
21*3 | Driver's air bag squib short-circuited
22*3 | Driver's air bag squib open-circuited
24*3 | Passenger's (front) air bag squib short-circuited
25*3 | Passenger's (front) air bag squib open-circuited
26*3 | Driver's pre-tensioner squib short-circuited
27*3 | Driver's pre-tensioner squib open-circuited
28*3 | Passenger's (front) pre-tensioner squib short-circuited
29*3 | Passenger's (front) pre-tensioner squib open-circuited
31 | SRS-ECU capacitor circuit voltage too high
32 | SRS-ECU capacitor circuit voltage too low
34*2 | SRS-ECU connector lock out of order
35 | Ignition of the air bag completed
39*4 | Simultaneous deployed
41*2 | Power supply voltage (IG1 (A) voltage) drops abnormally.
42*2 | Power supply voltage (IG1 (B) voltage) drops abnormally.
43*2 | SRS warning lamp circuit open-circuited
44*2 | SRS warning lamp circuit malfunction
45 | SRS-ECU non-volatile memory (EEPROM*1 ) and A/D converter system
46*2 *4 | Faulty installation
51 | Driver's air bag squib activating circuit short-circuited
52 | Driver's air bag squib activating circuit open-circuited
54 | Passenger's (front) air bag squib activating circuit short-circuited
55 | Passenger's (front) air bag squib activating circuit open-circuited
56 | Driver’s seat belt pre-tensioner (squib ignition drive circuit) system detected short
57 | Driver’s seat belt pre-tensioner (squib ignition drive circuit) system detected open
58 | Passenger’s seat belt pre-tensioner (squib ignition drive circuit) system detected short
59 | Passenger’s seat belt pre-tensioner (squib ignition drive circuit) system detected open
61 | Driver's air bag squib drive circuit (power supply side) short-circuited
62 | Driver's air bag squib drive circuit (earth side) short-circuited
64 | Passenger's (front) air bag squib drive circuit (power supply side) short-circuited
65 | Passenger's (front) air bag squib drive circuit (earth side) short-circuited
66 | Driver's pre-tensioner squib (power supply side) short-circuited
67 | Driver's pre-tensioner squib (earth side) short-circuited
68 | Passenger's (front) pre-tensioner squib drive circuit (power supply side) short-circuited
69 | Passenger's (front) pre-tensioner squib drive circuit (earth side) short-circuited
71*3 *5 | Side air bag squib (RH) short-circuited
72*3 *5 | Side air bag squib (RH) open-circuited
73*5 | Side air bag squib (RH) drive circuit shorted
74*5 | Side air bag squib (RH) drive circuit open
75*5 | Side air bag squib (RH) drive circuit (power supply side) shorted
76*5 | Side air bag squib (RH) drive circuit (earth side) shorted
79*5 | Side impact sensor (LH) communication error
81*3 *5 | Side air bag squib (LH) shot-circuited
82*3 *5 | Side air bag squib (LH) open-circuited
83*5 | Side air bag squib (LH) drive circuit shorted
84*5 | Side air bag squib (LH) drive circuit open
85*5 | Side air bag squib (LH) drive circuit (power supply side) shorted
86*5 | Side air bag squib (LH) drive circuit (earth side) shorted
89*5 | Side impact sensor (RH) communication error
91*2 *5 | Side impact sensor (LH) voltage error
92*5 | G-sensor of side impact sensor (LH) failure
93*5 | Side impact sensor (LH) communication impossible
94*2 *5 | Side impact sensor (RH) voltage error
95*5 | G-sensor of side impact sensor (RH) failure
96*5 | Side impact sensor (RH) communication impossible
NOTE: *1: Electrically Erasable Programmable ROM *2: This diagnosis code memory will be automatically cleared from the memory and the SRS warning lamp will be switched off when the system returns to normal condition. *3: The diagnosis codes will remain in memory and the SRS warning lamp will be switched off if the system returns to normal condition. *4: Vehicles without side air bag *5: Vehicles with side air bag
SERVICE DATA OUTPUT When the SRS-ECU detects a problem, it stores a diagnosis code and the duration that the problem has lasted in the non-volatile memory. In addition, how often a diagnosis code and duration are cleared by the MUT-II/III are stored in the non-volatile memory as a reference for service work. This data can be read by the MUT-II/III.
No. | Service Data Item | Applicability
--- | --- | ---
92 | Number indicating how often the memory is cleared | Maximum time to be stored: 250 days
93 | How long a problem has lasted (How long takes from the occurrence of the problem until the first air bag squid Igniting signal) | Maximum time to be stored: 9999 minutes (approximately 7days)
94 | How long a problem has lasted (How long from the first air bag squib igniting signal until now)

[52B] SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - - SYSTEM OPERATION - SRS-ECU | PRINT PAGE / INDEX / PRIOR / NEXT

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