1997 HONDA CIVIC Main relay

Engine Control Module/Powertrain Control Module (ECM/PCM)
('95 - 00 Models except Dl6Y5 engine with M/T)
NOTE:. When there is no Diagnostic Trouble Code lDTC) stored, the MIL will staY on if the SCS
seruice connector is connected and the ignition switch is on.. lf this symptom is intermittent, check for:- A loose No. 25 (METER) {7.5 A) fuse in the underdash fuse/relay box- A loose Fl E/M (15 Alluse in the undeFhood fuse/relay box- A loose No. 13 FUEL PUMPfuse (15 A) in the under-dash fuse/relay box- An intermittent shon in the wire between the ECM/PCM (A18) and the gauge assem'
- an intermittent short in the wire between the ECM/PCM (C19) and the MAP sensor- An intermittent short in the wire between the ECM/PCM {C28), the TP sensor, the
EGR valve lift sensor (D16Y5 engine) and/or the Fuel tank pressure sensor ('96 D16Y8
engine (coupe),'97 D16Y7 engine lcoupe: KL model, sodan: KL (LX) model)"g7
Dt6Y8 engine (coupe: all mod;ls, sedanl KL model),'98-all models,'99-al' models''00-all models.- PGM'FI main relay. See the oBD ll scan tool or Honda PGM Tester user's manuals for specific operating
instructrons,
ECM,/PCM CONNECTOR A I32PI
Wire side of {emale terminals
The Mrlfunction Indicator LamP{MlL) never comes on {even tor
two seconds) after ignition is
turned ON lll).
Turn the ignition switch ON lll).
- Repair shott or open in thowire bstwoon No. 25 IMETER)l?.5 A)tuse and gauga tsom_blv.- Reolace No. 25 (METERI (7.5
Alluse.
ls the low oil pressure light on?
Try to start the engine.
Check for an opon in the wire orbulb (MlL line):1. Turn the ignition switch OFF.2. Connect the ECM/PCM con'
nector terminal A18 to bodyground with a iumper wire.
3. Turn the ignition switch ON (ll)
Does the engine start?
- Repair open in tho wire3
betwoon ECM/PCM (A18) andgaugo .*tembly.- Rool.ce the MIL bulb.
Substitute a known-good ECM/
PCM and rochoc&. lf sYmptom/indication goes sw6y, repl.ce
tho original ECM/PCM.Turn the ignition switch OFF.Inspect Fl E/M (15 A)fuse in theunderhood Iuse/relay box.
Rop.ir short in the wirc
betwo€n Fl E/M (15 A) luso
and PGM-Fl mrin rGl.y.Reol.ce Fl E/M (15 A)tusa.
lnspect No. 13 FUEL PUMP {15 A}
luse in the under-dash fuse/relay
- Reoair short in the wiro
between No. 13 FUEL PUMP
115 Al luse sod PGM-FI mainrelay.- Reolace No. 13 FUEL PUMP115 A) tuse.
(To page 11 112)
(cont'd)
11-111
.f,

PGM-FI System
(From page'11-111)
Check loi an open in the wires(lGP linesl:1. Disconnect the lueliniector andIAC valve connectors.2. Turn the ignition switch ON (ll).
3, Measu re voltage betweenbody ground and ECM/PCMconnector terminals 81 andBg individually.
- Repair open in the wiro(3)between ECM/PCM lBl, B9land PGM-Fl main relay.- Check tor poor connectionsor loose wires al the PGM-FImain relav.- Test tho PGM-FI main rehy(3.e page 11-237).
ls there battery voltage?
Check tor an open in the wires(PG, LG lines):1. Reconnect the fuel iniectorand IAC valve connectors.2. Measure voltage betweenbody ground and ECM/PCMconnector terminals 82, 810,820 and 822 individually.
Repair open in the wirels)between ECM/PCM and G 101llocated ai the l6ft side of thointaks m.nifoldl thrt h.d morethan 1.0 V.
ls there lessthan 1.0 V?
Check for a short in the wires
{VCCI, VCC2 lin6s}:Measure voltage between bodyground and ECM/PCM connectorterminals C19 and C28 individually.Check toa a 3hort in s 3ensor:While measuring voltagebetween body ground and ECM/PC[/t connector terminals C19and C28 individually, disconnectthe 3P connector of each sensorone at time:. MAP sensor. TP sensor. EGR valve. Fueltank pressure sensor
ls there approx.5 V?
Reoair short in lhe wire betwe.enMAP 3ansor, TP sensor, EGRvalve, Fuel tank pres3ure 3ensorand ECM/PCM {Cl9, C28).
ls there approx. 5 V?
Substiiute a known-good ECM/PCM and racheck. ll symptom/indicetion goes eway, replaceth6 original ECM/PCM.Replace tho sansor that had.pprox. 5 V.
Engine Control Module/Powertrain
('99 - 00 Model except Dl6Y5 (M/Tl
Module (ECM/PCM)
(cont'd)
Control
engine)
ECM/PCM CONNECTOR B {25P)
LG1 (BRN/BLKI
Wire side of female terminals
ECM/PCM CONNECTOR C (31P)
female terminalsvcc2IYEL/BLUIvccl{YEL/RED)
Wire side of female terminals
11-112

ldle Gontrol System
ldle Air Control (lAG) Valve ('99 - 00 Dl6Y8 engine with M/T, Bt6A2 enginel
[Fl50g l ]h" scan tool indicates Diagnostic Trouble Code (DTC) P1508: A problem in the ldle Air Controt AC) vatve- CtrCUtt.
The IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the ECM inorder to maintain the proper idle speed.
IAC VALVE 2P CONNECTOR IC138'
la rcprI - {YEL/8LKI 2t--d,
Y-=
Wire side ot female terminals
Wire side of lemale terminals
VALVE
The MIL has boon r€oorted on.DTC P1508 is srored.
Probl6m verification:1. Do the ECM/PCM Reset Pro-cedure.2. Start the engine, and warm itup to normal operating lem-perature.
Intermittent tailure, system is OKat this timg. Check to. poor con-noctions or loose wires at C138{lAC valvel and ECM.
ls DTC P1508 indicated?
Ch6ck for an open in the wir€{lGPl lino}:1. Turn the ignition switch OFF.2. Disconnect the IAC valve 2Pconnector.3. Turn the ignition switch ON (ll).
4. Measure voltage between bodyground and the IAC valve 2Pconneclor termina I No.2,
Repair opon in the wire bgtwoenIAC valve and PGM-Fl main relay.
Check tof an open or short in thewire {IACV line}l1. Turn the ignition switch OFFand reconnect the IAC valve
2. Disconnect the ECM connectorB {25P).3. Turn the ignition switch ON (ll).
4. Measure voltage betweenbody ground and ECM conn€ctor terminal 823.
(To page 11-197)
1 1-1 96

ldle Control System
Starter Switch Signal ('96 - 98 Models,'99 - 00 D16Y5 engine with M/Tl
Thjs signals the ECM/PCM when the engine is cranking.
NOTE:. A/T: Transmission in E or E position. M/T: in neutral
a l32PlLGl
Wire side ot female lerminals
Check tor an open or short in thewire ISTS linel:Measure voltage between ECM/PCM connector terminals A9 andC6 with the ignition switch in thestart lllli position.
Inspect the No. 31 STARTER SIG-NAL (7.5 A) fuse in the underdashfuse/relay box.
- Repair .hort in the wirebotwoen tha ECM {C6l andtho No, 31 STARTER SIGNAL{7.5 Al tuss or the PGM-FImain relay,- Roolac. the No. 3'l STARTERSIGNAL l?.5 Al tu3€.
Staner 3witch signal is OK.
Repair opon in th6 wiro botweanih. ECII4/PCM (C6) and the No.31STARTER SIGNAL {7.5 Al tulo.
ECM/PCM CONNECTORS
{BRN/BLKISTS IBLU/ORNI
216910It3567a9l0
l2l3la15!6171a1920222att12t3l4t5t6171E
252l2A7t30232a2930
11-202

Fuel Supply System
System Description
The fuel supply system consists of a fuel tank, in-tank
high pressure fuel pump, PGM-FI main relay, fuelfilter,
fuel pressure regulator, fuel injectors. and fuel delivery
and return lines. This system delivers pressure-regu-
lated fuel to the fuel injectors and cuts the fuel delivery
when the engine is not running.
Fuel Pressure l'96 Modelsl
Relieving
Before disconnecting fuel pipes or hoses, release pres-
sure from the system by loosening the 6 mm service
bolt on top of the fuel filter.
. Do not smoke whil6 working on the fuel system.
Kgsp opon flames or sparks away from youl work
area.
. Be sure to relieve fuel pressure while the ignition
switch is off.
1. Write down the frequencies for the radio's preset
buttons.
2. Disconnect the battery negative cable from the bat-
tery negative terminal.
3. Remove the fuelfill cap,
4. Use a box end wrench on the 6 mm service bolt at
the fuel filter while holding the special banjo bolt
with another wrench,
5. Place a rag or shop towel over the 6 mm service bolt.
6, Slowly loosen the 6 mm service bolt one complete
rurn.
. A fuel pressure gauge can be attached at the 6 mm
service bolt hole.
. Always reDlace the washer between the service
bolt and the special banjo bolt whenever the ser-
vice bolt is loosened.
. Replace all washers whenever the bolts are
removeo.
11-230
Inspoction
1. Relieve fuel pressure.
2. Remove the service bolt on the fuel filter while hold-
ing the banjo bolt with another wrench. Attach the
special tool.
FUELPRESSUREGAUGE07406 - 00ir0(x)1
Start the engine. Measure the fuel pressure with the
engine idling and the vacuum hose of the fuel pres-
sure regulator disconnected from the fuel pressure
regulator and pinched. lf the engine will not start,
turn the ignition switch ON (ll), wait for two sec-
onds, turn it off, then back on again and read the
fuel pressure.
Pr€3sure should bo:
260 - 310 kPa (2.7 - 3.2 kgt/cmr, 38 - 46 psi)
Reconnect vacuum hose to the fuel pressure regulator,
Pressure should bo:
200 - 25O kPa l2.O - 2.5 kgf/cm', 28 - 36 psil
lf the fuel pressure is not as specified, first check the
fuel pump {see page 11-2361. lf the fuel pump is OK,
check the following:
. lf the fuel pressure is higher than specified,
inspect for;- Pinched or clogged fuel return hose or line.- Faulty fuel pressure regulator (see page 11-234).. lf the fuel pressure is lower than specified, inspect
for:- Clogged fuelfilter.- Faulty fuel pressure regulator {see page 11-234).- Fuel line leakage.
REGULATOB

Fuel Supply System
Fuel Pump
Testing
!@ Do not smoke during the test, Keep open
flame away from your work atea,
lf you suspect a problem with the fuel pump, check that the
fuel pump actually runs; when it is ON (ll), you will hear
some noise if you hold your ear to the fuel fill port with the
fuel fill cap removed. The fuel pump should run for two
seconds when ignition switch is first turned ON (ll). lf the
fuel pump does not make noise, check it as follows:
L Remove the seat cushion {see section 20).
2. Remove the access panel from the floor.
3. Make sure the ignition switch is OFF, then discon-
nect the Iueltank 2P connector.
4. Connect the PGM-FI main relay 7P connector termi-
nal No. 4 and No. 5 with a jumper wire.
PGM-R MAIN RELAY 7P CONNECTOR lC4,(|l
FUEL PUMP
IYEL/GRN}
IGN 1(YEL/GRNI
tcs6s)
FUEL PUMP(YEL/GRNI
Wire side oftemale torminals
JUMPER WIRE
Wire side of temale terminals
Check that battery voltage is available between the
fuel pump connector terminal No. 1 and body ground
when the ignition switch is turned ON (ll).
CONNECTOR
=
[t
L3l .i)
T
lf battery voltage is available, check the fuel pump
ground. lf the ground is OK, replace the fuel pump.
lf there is no voltage, check the wire harness (see
page 11-238).
11-236
Replacement
@E Do not smoke while working on tuel svs-
tem. Keep open llames away from your work area.
1. Remove the seat cushion (see section 20).
2. Remove the access panel trom the floor.
3. Disconnect the 2P connector from the fuel pump.
4. Remove the fuel pump mounting nuts.
5. Remove the fuel pump from the fuel tank.
6. Install pans in the reverse order of removal.
ACCESS PANEL
i

I
PGM-FlMain Relay
Description
The PGM-Fl main relav actuallv contains two individual
relays. This relay is located at the right side of the cowl.
One relay is energized whenever the ignition is on which
supplies the battery voltage to the ECM/PCM, power to
the luel iniectors, and power for the second relay. The
second relay is energized lor two seconds when the igni-
tion is switched ON (lll, and when the engine is running,
to supply power to the luel pump.
PGM-FIMAIN RELAY
J
I
t
FUEL PUMP
Relay Testing
NOTE:
. It the engine starts and continues lo run. the PGM Fl
main relay is OK.
. Use the terminal numbers below;
ignore the terminal numbers molded into the relay,
1. Remove the PGM Fl main relay.
2. Attach the battery positive terminal to the No. 2 ter-
minal and the battery negative terminal to the No 1
terminal of the PGM-Fl main relay. Then check for
continuity between the No.5 terminal and No 4ter-
minal of the PGM Fl main relay.
. lf there is continuity, go on to step 3.
. lf there is nocontinuity, replacethe PGM-Fl main
relay and retest.No. 3No. 1
To lGN. 1
To GROUND
To ST. SWITCH
To ECM/PCM {A161
To 8AT O
To ECM/PCM{(a11, A241, (81. B9l*l
To FUEL PUMP.r '99 model
3.Altach the batterv positive terminal to the No.5 ter-
minal and the battery negative terminal to the No. 3
terminal of the PGM-Fl main relay. Then check that
there is continuity between the No. 7 terminal and
No. 6 terminal of the PGM-Fl main relay.
. lf there is continuity, go on to step 4
. lf there is nocontinuity, replacethePGM-Fl main
relay and retest.
Attach the battery positive terminal to the No. 6 ter-
minal and the battery negative terminal to the No. 1
terminal of the PGM Fl main relay. Then check that
there is continuity between the No. 5 terminal and
No. 4 terminal of the PGM-Fi main relay.
. lf there is continuity, the PGM-Fl main relay is OK.
lf the fuel pump still does not work, go to Harness
Testing on the next page.
. lf there is no continuity, replace the PGM Fl main
4.
(cont'd)
11-237
relay and retest.

Fuel Supply System
PGM-FI Main Relay (cont'dl
Circuit Troubleshootin g
PGM.FI MAIN RELAY 7P CONNECTOR {C443)
GND{8LK)
Wire side of female terminals
/BLK}
- Engine will not start.- lnsoection of PGM-FI mainrelay and relay harne$.
Check for an open in the wire{GNO line}:l. Turn the ignition switch OFF.2. Disconnect the PGM-Fl mainrelay 7P connector.3. Check for continuity betweenthe PGM Fl main relay 7P con-nector terminal No.3 and bodyground.
Ropai. open in the wir€ betweenthe PGM-FI main .elav and G101.
Check for an open or short in thewire {BAT lin€}:N4easure voltage between thePGM-FI main relay 7P connectorterminal No. 7 and body ground.- Repair open or sho.t in thewire between the PGM-FI mainrelay and the Fl E/M {15 A}fus€.- Replace the Fl E/M (15 Allu3ein the under-hood fuse/relayoox.
ls lhere battery voltage?
Check tor an open or short in thewire {lGl line):1. Turn the ignition switch ON (ll).
2. Measure the voltage betweenthe PGM-Fl main relay 7P con'nector terminal No. 5 and bodyground.- Repair open or short in thewire betwoen the PGM-FI mainrelav and the No. 13 FUELPUMP (15 A)tuse.- R€place the No. 13 FUELPUMP {15 A} tus€ in the under-d.sh fus€/relay box.
ls there battery voltage?
Ch.ck for an open or short in thewire {STS lino}r1. Turn the ignition switch to theSTART (lll) position.NOTE:. M/T: Clutch pedal must beoepresseo.. A/T: Transmission in E or
E position.2, Measure the voltage betweenthe PGM-Fl main relay 7Pconnector terminal No, 2 andbody ground.
12
[,a567
123BAT
{WHTa56,
'96 98 models: (To page 1l 239)'99 - 00 models: (To page I l-240)
11-238,