1999 HONDA CIVIC fuel level

PGM-FI System
System Description (cont'dl
Lean Burn Control {D16Y5 engine: CvT)
The lean burn control system is based on the characteristic increase in crankshaft angular acceleration which occurs inwhen the air-fuel ratio gets leaner.
The CKF sensor, which is mounted on the crankshaft, monitors sngine speed, lf crankshaft angular acceleration falls belowa certain level (target air-fuel ratio level), the amount of injected fuel is reouceo.
lf crankshaft angular acceleration exceeds this level. the amount of fuel is increased.
This system improves fuel economy and driveability by controlling the amount of injected fuel in the lean burn rangeimmediatelv before combustion starts to deteriorate.
1 1-1 06
TOC/CKP/CYP SENSOR
MAP SENSOR
CKF SENSOR
ECM
Comparison oI current airfuel ratio to target ratio

JBulb Locations {Without Tachometer)
TRUNK INDICATORLIGHT {1.i1W}
.4 Wl
CHARGING SYSTEM LIGHT 11,4 W}
LTGHT (1.4 W)GAUGE LIGHT
SEAT BELTREMINDER LIGHT (1.4 WI
LOW ENGINE OIL PRESSUBE
INDICATOB LIGHT (1.4 WI
LOW FUEL INDICATORLrGl{T (3 W)
RIGHT TURN SIGNALINOICATOR LIGHT
(1.1Wt
GAUGE LIGHTS {3 WI
WASHER LEVELINDICATOR LIGHT{1.4 W} lcanad.l
HIGH BEAMINDICATOR LIGHTMALFUNCTIONINDICATORLAMP (MIL)
BULB {1.4 WI
{1.ilW)
LEFT TURN SIGNALINDICATOR LIGHT {1.4 WI
A/T GEAR POSITIONINDICATOR (1.12 x 6)(On the printed
circuit board)
sRs TND|CATOR 11.4 W)
{On the Drinted circuit board}
aBs tNDtcAToR t1.4 W)(On the printed circuit board)(3.{ Wt
o/ o \7 o
23-137

Fuel Gauge
Gauge/Sending Unit Test
!@ Do not smoke while working on tho fuel
system. Keep open tlame away trom your wotk atea.
NOTE: Refer to page 23-133 for the fuel gauge system
circuit.
'1. Check the No. 25 (7.5 A) fuse in the under-dash fuse/
relay box before testing.
2. Remove the access panel from the floor.
ACCESS PANEL
Disconnect the 3P connector from the fuel gauge
sending unit.
Connect the voltmeter positive probe to the No. 2
terminal and the negative probe to the No. I termi-
nal, then turn the ignition switch ON (ll).
There should be between 5 and 8 V.
. lf the voltage is as specified, go to step 5.
. lf the voltage is not as specified. check for:- an open in the YEUBLK or BLK wire.- poor ground (G552).
Turn the ignition switch OFF.
Attach a jumper wire between the No. 1 and No. 2
terminals, then turn the ignition switch ON (ll).
)\
23-142
1.Check that the pointer of the fuel gauge starts mov-
ing toward the "F" mark.
CAUTION: Turn the ignition switch OFF before thepoinier reaches "F" on ihe gauge dial. Failure to do
so may damage the fuel gauge.
NOTE: The fuel gauge is a bobbin (cross-coil) type,
hence the fuel level is continuously indicated even
when the ignition switch is OFF, and the pointer
moves more slowly than that of a bimetaltype.
. lf the pointer of the fuel gauge does not move at
all, replace the gauge.
. lf the gauge is OK. inspect the fuel gauge send-
ing unit.
Remove the fuel gauge sending unit as shown.
Japan-produced
USA, Canada-produced

J
9. lMeasure the resistance between the No 1 and No. 2
terminals at E {EMPTY), 112 \HALF FULL) and F
(FULL) by moving the lloat.
USA, Canada-produced {Ceramic board type):
Too ot lhe workbench (Bottom of the fuel tank)
ll the resistance readings are beyond the range. replace
the fuel gauge sending unit
Float PositionE1t2F
Resistance (0)105 - 10829.5 - 35.53.5-5
Jaoan-Ploduced (Wire-wound typel:
Float PositionE1/2F
Resistance (O)105 - 11025.5 - 39.5
Low Fuel Indicator Light Test
NOTE: For the low fuel indicator circuit diagram, refer to
the gauge assembly circuit diagram (see page 23'2311.
1. Check the No. 25 (7 5 A) luse in the driver's under
dash fuse/relay box before testing
2. Park the vehicle on level ground.
3.
4.
Drain the luel into an approved container. Reinstall
the fueltank drain bolt with a new washer.
Add less than 4L (1 1 U.S Gal, 0.9 lmp Gal) of fuel,
and turn the ignition switch ON (ll). The low fuel
indicator light should come on within four minutes'
. lf the light comes on within four minutes, go to
step 8.
. lf the light does not come on within four min-
utes, go to step 5.
Remove the access panel lrom the Iloor'
Turn the ignition switch OFF, then disconnect the
fuel tank sending unit 3P connector.
Connect the fuel tank sending unit 3P terminals No'
1 and No. 3 with a jumPer wire
. lf the light comes on, replace the fuel gauge
sending unit (see Page 23 1421
. lf the light does not come on, check for:
- An open in the GRN/YEL wire between the
fuel gauge sending unit and the fuel gauge
- A blown bulb.- A poor ground (G552)
6.
1.
female terminals
8. Add 4L {1.1 U.S. Gal, 0 9 lmp Gal) of fuel The light
should go off within four minutes.
23-143

Ground-to-Components I ndex
f.,lONOTE: All ground wires are BLK unless otherwise noted.
GroundPageComponents or Circuit Grounded
Battery (BLKYEL)
Steering pump bracket
t+-rg ITransmission housing
l
G101
(-1)
G101
(-2)
14-2
and
14-3
ano
14-1
Powertrain or engine control module (PG1 and pG2 are BLK: LG1 and LG2 are
BRN/BLK), EGR control solenoid valve (CW, EGR valve and lift sensor (Dt6yS enginewith M,/T), Engine coolant temperature switch, pGM-Fl main relay, power steeringpressure switch (USA), Primary HO2S (D16Y5 engine with l\/,/T), Vehicle speed sensor,VTEC pressure switch (D16Y5/D16Y8 engines), CKF sensor (BRN/BLK), Transmission
control module (CYf) (Pc1 is BLK: LG1 is BRN/BLK)
Shielding betvveen the PCM or ECM and these components (all have BRN/BLK wires):
CKF sensor, TDC/CKP/CYP sensor. Primary and secondary heated oxygen sensors.
Knock sensor (CWDl6YB engine), Mainshaft speed sensor (AiT except CVT),
I Countershaft speed sensor (A/T except CVf)
Shielding between the TCM and these components (CVT) (all have BRN/BLK wires):
Drive pulley speed sensor, Driven pulley speed sensor, Secondary gear shaft
speed sensor
Powertrain or engine control module (PG1 and pG2 are BLK; LG1 and LGz are
BRN/BLK), EGR control solenoid valve (D16Y5 engine), EGR valve (Dt685), Engine
coolant temperature switch, Fuel pressure regulator shut-off solenoid valve (D1685),
PGM-FI main relay, Power steering pressure switch (USA), Vehicle speed sensor, VTECpressure switch (All except D16Y7 engine), CKF sensor (A

except 81642) (BRN/BLK)
Shielding between the PCM or ECM and these components (all have BRN/BLK wires):
CKF sensor, TDC/CKP/CYP sensor, Primary and secondary heated oxygen sensors,
Knock sensor (All except D16Y7 engine), i/ainshaft speed sensor (Arf except CW),
Countershaft speed sensor (A,/T except CVf), Drive pulley speed sensor (CW), Drivenpulley speed sensor (CVT), Secondary gear shaft speed sensor (CVf)
I Badiator fan motor, Right front parking/turn signat tight, Right headtight
G20214-4I Cruise control actuator, Left front parking/turn signal lights, Left headlight, Rear window
I washer motor, Windshield washer motor, Washer fluid level switch (,99-'00 Canada)
G401| +-o
and
14-7
Accessory power socket, Brake fluid level switch, Clutch interlock switch (M/T), Clutchswitch (lillT with cruise/D16Y5 engine with MfD, Combination wiper switch (Z wires),
Cruise control main switch, Cruise control unit, Dash lights brightness controller, Data
link connector, Daytime running lights control unit (Canada), Gauge assembly, Horn('96-'97 models), Integrated control unit, Interlock control unit (ArI), Keyless door lock
control unit ('99-'00 models with keyless), Moonroof close and open relays, Moonroof
switch, Park pin switch (A/r), Power window relay, Rear window defogger relay, Rear
window defogger switch ('96-'98 models), Steering lock, Stereo radio tuner (,96-,98
USA: LX, EX, and HX), Turn signal/hazard relay, Windshield wiper motor.....plus
everything grounded through G402
6-6

How the Gircuit Works
All Except GX
Do not smoke while working on the fuel system.
Keep open flame away trom the work area. Drain
fuel only into an approved container.
A thermistor is mounted in the fuel tank unit. When
the thermistor is cool, its resistance is very high.
When the thermistor's temperature increases, its
resistance decreases. Fuel in the fuel tank transters
heat away lrom the thermistor fast enough to keep it
cool so the thermistor's resistance stays high and
lhe low fuel indicator light does not come on. When
the fuel level drops below the thermistor, the
thermistor's temoerature increases. Without the fuel
to cool it, the thermistor's resislance decreases,
allowing current to llow through the low fuel
indicator light and the thermistor to ground, and the
low fuel indicator light comes on.
Refer to the Service Manual (Section 23, Electrical)
for specific tests or troubleshooting procedures.
GX
The PCM turns on the low fuel indicator light when
the fuel level is low. The PCM will also blink the
indicator light when a problem is detected by the
fuel tank pressure sensor or the fuel tank
temperature sensor.
Refer to the Service Manual GX Supplement
(Section 11 , Fuel and Emissions) for specific tests
or troubleshooting procedures.
74-1

Connector Views (conrd)
71. Gauge Assembly
- Left side of dash
Connector A (A/T only)
- Green- On dashboard wire harness
1 YEL (lgnition input)
2 RED/BLK (Headlight
switch ON input)
3 RED(Dash light brightnesscontroller input)
4 BLU (L or 2indicator control)
6 D16Y7/D16Y8:BRN (Not used)
8 BLK (G401)
Connector B
- Blue- On dashboard wire harness
2 BLK (G401)
3 BLU/BLK (Trunk openindicator light control)
4 GRN/YEL (Hazard
warning switch input)
5 GRN/RED(Brake system indicatorlight control)
6 RED/BLU (Seat beltindicator light control)
7 '96-'97 model: BLU,ryEL(not used)
8 Except GX: GRN/YELGX: 8LU/GRN(Low fuel indicator lightcontrol)
9 D16Y7/D16Y8: YEL01685/016Y5:GRN/BLK(D4 or D indicatorcontrol)
10 GRN (03 or Sindicator control)
11 RED(N indicator control)
12 WHT(F indicator control)
13 BLI(BLU(P indicator control)
14 LT GBN(Park/neutral output)
10 Except GX: YEUBLKcX: ORN/BLU(Fuel gauge controlinput)
11 BLUAVHT(Vehicle speed sensor(VSS) input)
12 YEUGRN (Engine
coolant temperaturesending unit input)
14
15 BLI(IVHT(lgnition input)
16 WHT/BLU(Charging systemindicator light control)
202-30
Connector C
- Blue- On dashboard wire harness
1 *: YEL (lgnition input)
2 *: PNK (Washer lluidlevel input)
3 YEUBED(Low oil pressureindicator light control)
4 YEL (lgnition input)
5 GRN/ORN (Malfunctionindicator light control)
6 RED/GRN
{Lights on Hl input)
7 GBN/RED (Hazardwarning switch input)
*= '99-'00: All except CVT
Connector D
- Orange- On dashboard wire harness
BLU/RED (ABS
indicator light control)
8 BLU(Engine speed input)
10
12 FED(Dash light brightnesscontroller input)
13 RED/BLK (Headlightswitch ON input)
I
2
3
4
5
BLK (G401)
YEL (lgnition input)