srs HONDA CIVIC 1999 6.G Repair Manual

Gomponent/Wiring Locations
Index: Without Front Passenger's Airbag (some Canada Modelsl
SRS INDICATOR LIGHT (ln the gauge assembly)Troubleshooting, page 24-13Gauge assembly, section 23
DRIVER'S AIRSAGReplacement,page 24-67Disposal, page 24-70
SRS UNITGROUNO
To HORN SWITCH
SRS MAIN HARNESS
SRS UNIT{lncluding safing sensorand impact sensor)Replacement. page 24,76
To CRUISE CONTROLSET/RESUME SWITCH
oo/ \oo
To DRIVER,S AIRBAG
DASHBOARD WIRE HARNESSto SRS INDICATOR LIGHT inGAUGE ASSEMBLY5P CONNECTOR
SERVICE CHECKCONNECTOR {2P}IB8N, BLKI
SRS MAINto UNDER-DASHFUSE/RELAY BOX2P CONNECTOR
SRS MAIN HARNESSto SRS UNIT18P CONNECTOR
SRS MAIN HARNESSto MAINWIREHARNESS3P CONNECTOR
MEMORY ERASE SIGNAL(MES) CONNECTON (2P'
IGRY, GRYI o. IGRN, GRNI
MAIN WIRE HARNESSto DASHBOARD WIRE HARNESS24P CONNECTOR
24-4
DUMMY RESISTOB

Description
)
The sRS is a safety device which, when used in coniunction with the seat belt, is designed to help protect the driver land
front passenger) in a frontal impact exceeding a certain set limit. The system consists of the sRS unit {including safing
sensor and impact sensor), the cable reel, the driver's airbag (and front passenger's airbag)
FRONT PASSENGEB'SAIRAAG
DRIVER'S AIRBAG
CABLE REEL
SRS UNtT
t
Operation
The main circuit in the SRS unit senses and judges the force of impact and, if necessary, ignites the inflator charge(s) lf
battery voltage is too low or power is disconnected due to the impact, the voltage regulator and the back-up power clrcult
resoectivelv will keep voltage at a constant level.
For the SRS to operate:
(1) The impact sensor must activate. and send electric signals to the mlcroprocessor'
(2) The microprocessor must compute the signals' and must send signals to the airbag inflator(s)'
{3) The inflator(s) must ignite and deploy the airbag(s)'
_"-_-l
Ir3B!#h i
!.. I
ffi,*
Self-diagnosis System
A self-diagnosis circuit is built into the SRS unit; when the ignition switch is turned ON (ll), the SRS indicator light comes
on and goes off after about six seconds if the system is operating normally
lf the liglt does not come on, or does not go off after six seconds, or if it comes on while driving, it indicates an abnormal-
ity in the system. The system must be inspected and repaired as soon as possible
For better serviceability, the memory will store the cause of the malfunctlon, and the data link circuit passes on the infor-
mation from the memory to the data link connector (DLC). This intormation can be read with the Honda PGM Tesler con-
nected to the DLC (16P).
l,
24-5

Circuit Diagram
UNDER-HOOD FUSE/RELAY 8OXIGNITIONSWITCH
WHT/8LI( +WHT
Brake systsm light
passenger's airbag
l----ltlI DUMMY II BESISTOR I
tll
tl
la rl
MEMORY ERASESIGNAT IMES)CONNECTOR I2P)
GRY{GRN)
I
BRN BRN
tl.-l- .-r-\./ \./
ECM/PCM SERVICECHECKCONNECTOR
ILT 8LU
I
t'7
DATA LINKCONNECTOR{DLC) {r6P)
GRY GRY(GRN) IGNN)
V:
G801
Teminalside oi thal€ terminals
24-6
4''
SRS UNIT TERMINALSG40tG402
SBS INDICATOR CIRCUIT{ln the gauge assembly)
PGM_FI
DRIVER'SAIRBAGINFLATOR
10 14 r 13 6 7(VAl 3{VBlSRS UNIT16 17 t5 9 18 8

Precautions/ Procedures
)General Precautions
r Carefully inspect any SRS part before you install it Do
not install any part that shows signs of being dropped
or improperly handled' such as dents, cracks or defor-
mation:
- Airbags- Cable reel
- SRS unit
-
Use only a digital multimeter to check the system lf
it's not a Honda multimeter, make sure its output ls
1O mA (0.01 A) or less when switched to the smallest
value in the ohmmeter range. A tester with a higher
output could damage the airbag circuit or cause acci-
dental deployment and possible injury'
I Do not install used SRS parts from another vehicle
When making SRS repairs, use only new pans'
) Except when performing electrical inspections'
always disconnect both the negative cable and posl-
tive cable from the battery, and wait at least three
minutes before beginning work
r Replacement of the combination light and wiper/
washer switches and cruise control switch can be
done without removing the steering wheel:
- Combinalion light and wiper/washer switch replace
ment, see section 23
- Cruise control sevresume switch replacement' see
section 23.
. Whenever the ignition switch is ON {ll), or has been
turned OFF for less than three minutes' be careful not
to bump the SRS unit; the airbag(s) could accidental-
ly deploy and cause damage or injury'
. Whenever the airbag{s) has(have) been activated'
replace the SRS unit.l,
2+7
Airbag Handling and Storage
Do not try to disassemble the airbag assembly. lt has no
serviceable parts Once an airbag has been operated
(deployed). it cannot be repaired or reused'
For temporary storage of the airbag assembly during ser-
vice. olease observe the following precauttons:
. store the .emoved airbag assemblv with the pad sur-
face uo The driver's (and front passenger's) airbag
connecto''s'-as {have) a built.in short contact (see
page 2a-l 1
: | ..r r-+r-a k imninncrlv slorcd lace down,-""dd.r6t dtatltt-,tl could propel the unit whh enough
force lo c.usa 3a.ix! intury
AIRBAG CONNECTORS(With built in shon contact)
. Store the removed airbag assembly on a secure flat
surface away from any high heat source {exceeding
212"FI1OO"CJ and free of any oil' grease, detergent or
water.
CAUTION: lmproper handling or storage can intern'lJy
damage the airbag assembly, making it inoperativo
lf you suspect the airbag assembly has been dam€cd'
inslall a new unit. and relsr lo the Deployment/DisPG'l
olocedules for disposing ol the damaged airbag

Precautions/Procedu res
SRS Unit Precautions
Take extra care when painting or doing body work inthe area below the dashboard. Avoid direct exDosureof the SRS unit or wiring to heat guns, welding. orsprayang equipment.
Disconnect the airbag connector(s) before discon-necting SRS harness connectors (see page24-1|1J.
After any degree of frontal body damage, or after acollision without airbag deployment, inspect the SRSunit for physical damage. lf it is dented. cracked, ordeformed, replace it.
Be sure the SRS unit is installed securely.
Do not disassemble the SRS unit.
Store the SRS unit in a cool (less than about 104.F/40"C) and dry (less than 80% humidity, no moisture)place. Do not spill water or oil on the SRS unit, andkeep it away from dust.
During installation or replacement, be careful not tobump (impact wrench, hammer, etc.) the area aroundthe SRS unit. The airbag(s) could accidentally deptoyand cause damage or injury.
24-8
Inspection After Deployment
After a collision ln which the airbag(s) was (were)
deployed, replace the SRS unit, and inspect the following:
1. Inspect all the SRS wire harnesses. Replace. don,trepair, any damaged harnesses.
2. Inspect the cable reel for heat damage. lf there is anydamage, replace the cable reel.
3. After the vehicle is completely repaired, turn theignition switch on. lf the SRS indicator light comeson for about six seconds and then goes off. the SRSsystem is OK. lf the indicator light does not functionproperly, go to SRS Troubleshooting.

)
Wiring Precautions
. Never attempt to modify, splice or repair SRS wiring'
NOTE: SRS wiring can be identified by special yellow
outer Protective covering.
8e sure to install the harness wires so that they are not
oinched or interfering with other parts.
t
Make sure all SRS ground locations are clean and
grounds are securely fastened for optimum metal-to-
metal contact. Poor grounding can cause intermittent
problems that are difficult to diagnose.
a,
24-9
Backprobing Spring'loaded Lock
Gonnectors
. When checking voltage or resistance on this type of
connector the flrst time, it is necessary to remove lne
retainer to insert tester probes from the wire side.
NOTE: lt is not necessary to reinstall the removed
retainer; the terminals wi I stay locked in the connec-
tor housrng.
To remove the retainer, insert a flat tip screwdriver
between connector body and retainer, and carefully
pry out the retainer.
NOTE: Take care not to break the connector.
FLAT TIPSCBEWDRIVER
RETAINER* Discard after removal.
RETAINER

Preca utions/Procedures
Spring-loaded Lock Connector
Some SRS system connectors have a spring-loaded lock.
Disconnecting
To release the lock, pull the spring-loaded sleeve towardthe stop while holding the opposite half of the connecror.Then pull the connector halves apart.
NOTE: Be sure to pull
connector half.
on the sleeve and not on the
SPRING-LOADEOSLEEVE
Do not pull on thishalf of the connector.
Connecting
1. Hold the pawl-side connector half, and press on theback of the sleeve-side connector half in the directionshown. As the two connector halves are pressed
together, the sleeve is pushed back by the pawl.
NOTE: Do not touch the sleeve.
When the connector halves are completely connected,the pawl is released, and the spring-loaded sleevelocks the connector.SPRING.LOADEDSLEEVE
24-10
Spring-loaded Lock Connector with
Built-in Short Contact
The driver's ajrbag (and front passenger,s) airbag has(have) a spring-loaded lock connector with a builr-inshort contact. When this connector is disconnected, thepower terminal and the ground terminal in the airbaaconnector are automatically shoned.
Connector halves disconnected:
SHORT CONTACT
Conneqtor halves connected:
GROUND TERMINAL
CABLE REEL CONNECTOR
GROUND TERMINAL

)Disconnecting the Airbag Connector(sl
'1. Disconnect the negative battery cable, and wait at
least three minutes.
2. Disconnect the airbag connector(sl.
Driver's Side:
. Remove the access panel from the steering wheel'
then disconnect the driver's airbag 2P connector and
cable reel 2P connector.
!@@ To prevent sccidental 8irbag deployment, turn th€ ignition switch oFF. disconncct th€ negative battery
ffi, "nd *"it thr"e minutes b€fore disconnocting any sRS conn'ctors'
. Before disconnecting the SRS main harness (A) from the SRS unit' disconnect both airbags (C' D)'
.Beforedisconnectingthecab|ereel2Pconnector(B),disconnectthedriver,sairbag2Pconnector(c).
F ont PasEanga/3 Side:
. Remove the glove box. then disconnect the front pas-
senger's airbag 2P connector and SRS main harness
2P connector.t
FRONT PASSENGER'SAIRBAG2P CONNECTOR
CABTT REEL2?CONNECTOR
AOCESS PANEL
a,
24-11

Precautions/Procedu res
Steering-related Precautions
Stesring Wheel and Cable Reol Alignment
NOTE: To avoid misalignment of the steering wheel on
reassembly, make sure the wheels are turned straight
ahead before removing the steering wheel.
Rotate the cable reel clockwise until it stops.
Then rotate it counterclockwise {approximately two and
a half turns) until the arrow mark on the cable reel label
points straight up.
24-12
:l
St€€rin9 Column Removal
CAUTION:
. Eefore removing thg stggring column. disconnect the
connsstor bqtween the cable r€el and th€ SRS msin
harness.
. lf the stoering column is going to be romoved with-
out dismounting th6 stoering wheel, lock the steer-
ing by turning the ignition key to o-LOCK position, or
remove the key trom the ignition switch so that the
steering wheel will not turn.
NOTE:
When the airbag and cable reel are disconnected,
don't reconnect the battery cable. lf the battery is
reconnected and the ignition switch is turned ON (ll),
the SRS unit will store this as an open in the driver's
airbag inflator, and the SRS indicator light will come
on.
For disconnecting the spring-loaded lock type con-
nector, refer to page 24-'10.
SRS MAIN HARNESS2P CONNECTOR
Do not replace the original steering wheel with any other
design because it will make it impossible to properly
install the airbag (only use genuine Honda replacement
parts).
After reassembly, confirm the wheels are still turned
straight ahead and that the steering wheel spoke angle
is correct. lf minor spoke angle adjustment is necessary,
do so only by adjusting the tie-rods, not by removing
and repositioning the steering wheel.

rl
Troubleshooting
t)
Self-diagnostic Procedures
The self-diagnostic function of the SRS system allows it to locate the causes of system problems and to store this informa' I
tion in memory. For easier troubleshooting, this data can be retrieved via a data link circuit l
. When you turn the ignition switch ON (ll), the SRS indicator will come on. ll it goes off after six seconds. the system is
norma l.
. lf there is an abnormality, the system locates and defines the problem, stores this information in memory, and turns
the sRS indicator light on. The data will remain in the memory even when the ignition switch is turned off or if the bat-
tery is disconnected.
o when you connect the scs service connector to the service check connector (2P), and turn the ignition switch oN (ll),
thesRsindicator|ightwi||indicatethediagnostictroub|ecode(DTC)bythenumberofb|inks.
. After reading and recording the DTC. proceed with the troubleshooting for this code'
Precauiions
.Useon|yadigita|mU|timetertocheckthesystem'|fit,snotaHondamu|timeter,makesureitsoutputisl0mA(0.01A)
or|esswhenSwitchedtothesma||estva|ueintheohmmeterrange,AtesterwithahigheroUtpUtcoulddamagethe
airbag circuit or cause accidental airbag deployment and possible injury'
r when-ever the ignition switch is oN (ll). or has been turned oFF for lessthan three minutes, be careful nottobumpthe
SRS unit; the airbags could accidentally deploy and cause damage or injuries
. Before you ,"n1ou" th" SRS main harness, disconnect the driver's airbag connector (and the front passenger's airbag
connector).
. Make sure the battery is sufficiently charged {see section 23}. lf the battery is dead or low, measuring valLles won t be
correct.
. Do not touch a tester probe to the terminals in the sRS unit or harness connectors, and do not connect the terminals
with a jumper wire. Use only the backprobe set or the special tools'
For backprobing spring-loaded lock type connectors, refer to page 24-9'
Reading the DTC
when the SRS indicator light is on, read the DTC using one of these methods:
A. Connect the Honda PGM Tester to the 16P Data Link Connector {DLC), and follow the tester's prompts lf the tester
indicatesnoDTc,DTcg-1orDTc9-2,doub|e-checkbyjumpingtheservicecheckconnectorandwatchingthesRS
indicator light (see next Page)
HONDA PGM TESTER
DATA LINK CONNECTOR Il6PI
l,
24-13