air conditioning HONDA CIVIC 1999 6.G User Guide

3.
5.
6.
1.
Fuel Cut-off Control
. During deceleration with the throttle valve closed, current to the fuel injectors is cut off to improve fuel economy at
speeds over the following rpm:. D16Y5 engine (M/T):850 rpm. D]6Y5 engine (CVT), D'16Y8 engine (USA M/T): 920 rpm
. Dl6Y8 engine (USA A,/I), D16Y7 engine (USA A,/T);910 rpm
. D16Y8 engine (Canada M/T), D16Y7 engine (canada): 990 rpm
' D16Y8 engine (Canada M/T): 1,000 rpm
. 816A2 engine: 970 rpm
. Fuel cut-off action also takes place when engine speed exceeds 6,900 rpm (D16Y5, D16Y7 engine; D'16Y8 engine:
7,000 rpm. 816A2 engine: 8.100 rpm), regardless of the position of the throttle valve, to protect the engine from
over-rewing. With '99 Dl6Y7 engine (A,/T) and '99 D16Y8 engine (A./T), the PCM cuts the fuel at engine speeds over
5,000 rpm when the vehicle is not moving.
IVC Compressor Clutch Relay
When the ECM/PCM receives a demand for cooling from the air conditioning system, it delays the compressor from
being energized, and enriches the mixture to assure smooth transition to the A,/C mode
Evaporative Emission (EVAP) Purge Control Solenoid Valve*'
When the engine coolant temperature is above 154'F (68'C). the ECM/PCM controls the EVAP purge control solenoid
valve which controls vacuum to the EVAP purge control canister.
Evaporative Emission (EVAP) Purge Control Solenoid Valve*a
When the engine coolant temperature above 154"F (68"C), intake air temperature above 32"F (0'C) and vehicle speed
above 0 mile (0 km/h) or [Ay'C compressor clutch on and intake air temperature above 160"F (41'C)], the ECM/PCM
controls the EVAP purge control solenoid valve which controls vacuum to the EVAP purge control canister.
Exhaust Gas Recirculation (EGR) Control Solenoid Valve*?
When EGR is required for control of oxides of nitrogen (NOx) emissions. the ECM controls the EGR control solenoid
valve which supplies regulated vacuum to the EGR valve
Alternator Control
The system controls the voltage generated at the alternator in accordance with the electrical load and driving mode,
which reduces the engine load to improve the fuel economy.
ECM/PCM Fail-safe/Back-up Functions
1. Fail safe Function
When an abnormality occurs in a signal from a sensor, the ECM/PCM ignores that signal and assumes a pre-pro-
grammed value for that sensor that allows the engine to continue to run.
2. Back-uD Function
When an abnormality occurs in the ECM/PCM itself, the fuel injectors are controlled by a back-up circuit independent
of the system in order to permit minimal driving.
3. Self diagnosis Function lMalfunction Indicator Lamp (MlL)l
When an abnormality occurs in a signal from a sensor, the ECM/PCM supplies ground for the lvllL and stores the DTC
in erasable memory. When the ignition is initially turned on, the ECM/PCM supplies ground for the MIL for two sec-
onds to check the MIL bulb condition.
4. Two Trip Detection Method
To prevent false indications, the Two Trip Detection Method is used for the HO2S, fuel metering-related. idle control
system, ECT sensor, EGR system and EVAP control system self-diagnostic functions. When an abnormality occurs,
the ECM/PCM stores it in its memory. When the same abnormality recurs after the ignition switch is turned OFF and
ON 0l) again, the ECM/PCM informs the driver by lighting the MlL. However, to ease troubleshooting, this function is
cancelled when you jump the service check connector. The MIL will then blink immediately when an abnormality
occurs,
5. Two (or Three) Driving Cycle Detection Method
A "Driving Cycle" consists ot starting the engine. beginning closed loop operation, and stopping the engine. lf misfir-
ing that increases emissions is detected during two consecutive driving cycles, or TWC deterioration is detected dur-
ing three consecutive driving cycles, the ECM/PCM turns the MIL on. However, to ease troubleshooting, this function
is cancelled when you jump the service check connector. The MIL will then blink immediately when an abnormality
occurs.
(cont'd)
1 1-1 05
.1.

1.After the engine starts, the lAc valve opens for a certain time. The amount of air is increased to raise the idle speed
about 150 - 300 rpm.
When the coolant temperature is tow, the IAC valve is opened to obtain the proper fast idle speed. The amount of
bypassed air is thus controlled in relation to the engine coolant temperature'
IOLE SPEED
lrpml
176
80
ENGI ECOOLANI TEMPERATURE
t" Fl
toc)
ll
't.Whentheid|espeedisoutofspeciiicationandthescantoo|doesnotindicateDiagnosticTroub|ecode(DTc)P0505
or P1508. check the following items:
. Adiust the idle speed {see page 11-220}
. Starter switch signal (see page 11-202)
. Air conditioning signal (see page l1-204)
. ALT FR signal (see Page 11-2081
' Brake switch signal (see page 11-210)
. PSP switch signal (excapt Canada model) (see page 11-212)
. A,/T gear position signal {see section 14, Dl6Y5 engine (CVT):
page 11-216). Clutch switch signal (D16Y5 engine with M/T) (see page 11-218)
. Hoses and connections
' IAC valve and its mounting O-rings
lf the above items are normal, substitute a known-good IAC valve and readjust the idle speed (see page 11-220)
|ftheid|espeedsti||cannotbeadjustedtospecification(andthescantoo|doesnotindicateDTcP0505orP]50S)
after IAC valve replacement. substitute a known-good ECM/PCM and recheck. lf symptom goes away, replace the
original ECM/PCM.

ldle Gontrol System
Air Gonditioning Signal ('96 - 98 Models, '99 - 00 Dl6Y5 engine with M/Tl
a {32P1ECM/PCM CONNECTORS
Wire side of female terminals
c l3lPl
This sjgnals the ECM/PCM when there is a demand for cooling from the air conditioning system.
(To page 11-205)
Check for a short in the wire{ACS line):1. Turn the ignition switch OFF.2. Disconnect the A/C pressure
switch 2P connector {see section 22).3. Turn the ignition switch ON (ll).
4. Measure vo lta ge betweenECM/PCM connector termi-nals C5 and A9.
Check for a .hort in the wi.e {ACSline):1. Turn the ignition switch OFF.2. Disconnect the ECM/PCM con-nector C (3lPi.
3. Check tor continuity betweenbody ground and ECM/PCMconnector terminal C5,
ls there approx. 5 V?
Reotir short in the wi.e betweenthe ECM/PCM lc5l and rhe A/Cpressure switch.
ls there continuity?
- Substitute a known-goodECM/rcM .nd re.fieck. f Dre-scribed voltage is now availtble, replace the original ECft4/PCM,- See the air conditioner inspe-tion ls€e s€ction 221.
Check tor an op€n in the wireIACC lin6l:1. Turn the ignition switch OFF.2. Reconnect the A/C pressure
switch 2P connector.3. Turn the ignition switch ON (ll).
4. Momentarily connect ECM/PCM connector terminals A9and A17 with a jumper wire
LGl IBRN/8LKIACS {BLU/RED)
2361I9't0Itt3a89t0
12't31al5l617t8t920232all12l3l!ai5!617'tE
252l2A2930232a252930
ACS (BLU/BEDI
LGl IBRN/BLKI
123aslslrl lolgl ro lrr I
121314l516y)nltslnl/@) zr I zr I
25271!M1 1-/r
ACC
11-204
IBLK/RED)JUMPER WIRE

(From page 11-204)
Check for an open in the wir€(ACC linel:Momentarily connect underhood
fuse/relay box 9P connector teF
minal No. 5 to body ground with
a iumper wire several times.
ls there a clicking noise from
the IVC compressor clutch?
See air conditionor inspection(see 3oction 221.ls there a clicking noise from
the Py'C compressor clutch?
Repair open in the wire between
rhe ECM/PCM lAl7l and th6
under-hood fu3e/rolaY box 9P
connector lC352l.
Check for the oPeration of the
Alcl1. Start the engine.2. Turn the blower switch ON
3. Turn the AJC switch ON.
Chock tor an open in the wire
IACS linel:Measure voltage between ECM/
PCM connector terminals A9 and
c5.
Does the Ay'C operate?
Air conditioning signal is OK.Repair open in the wire b€tweenthe EcM/PcM lC5) and the A/c
3witch.ls there less than 1.0 V?
- Substiiute a known-goodECM/PCM and recheck ll
symptom/indication 9oesaway, .oplace the originalECM/PCM.- See the air condhioner insP€c_tion {see s€c{ion 22).
UNDER.HOOD FUSE/BELAYBOX 9P CONNECTOR 1C352)
12Ia
589
ACC (BLK/RI
Wire side ofACC (BLK/REDI
Wire side of female
terminals
JUMPERWIRE
ECM/PCM CONNECTORSrfA t32P)
LGlc {31Pl
t
(BRN/BLK)ACS IBLU/RED)
I23a9101t3I89t0
121315l611la1920232att12't3la't5t617ta
25272A2930232a2930
Wire side of lemale terminals

ldle Control System
Air Conditioning Signal ('99 - 00 Models except Dl6Y5 engine with M/Tl
This signals the ECM/PCM when there is a demand for cooling from the air conditioning system.
ECM/PCM CONNECTORS
a l32P)
ECM/PCM CONNECTOR A {32P)
Wire side of female terminals
ECM/PCM CONNECTORS
A (32P1
Chock tor a short in ihe wi.e(ACS lin6):1. Turn the ignition switch OFF.2. Disconnect the A/C pressure
switch 2P connector.3. Turn the ignition switch ON (ll).
4. Measure vo ltage betweenECM/PCM connector terminals A27 and 820.
Check for a short in the wire (ACS
linel:'1. Turn the ignition switch OFF.2. Disconnect the ECM/PCM connector A (32P).
3. Check lor continuity betweenbody ground and ECM/PCMconnector terminal A27.
Reoair short in lhe wi.e botweonthe ECM/PCM (A271 and rhe A/Cpressure swilch.
Srr66tituto a known{ood ECM/PCt4 tnd rechock. It prascrib€dvoltage is now available, re-plac€ the original ECM/rcM.Soo the air conditioner insoec-tion {see s€ction 22}.
Check to. an opon in tho wi.e(ACC linel:1. Turn the ignition switch OFF.2. Reconnect the A/C pressure
switch 2P conneclor.3. Turn the ignition switch ON (ll).
4. Momentarily connect ECN4/PCM connector terminals A17and 820 with a jumper wire
(To page '! 1-207)
11-206
LGl {BRN/BLK)

I
JUMP€RWIRE
UNDER-HOOO FUSE/RELAYsox 9P coNNEcroR lca52l
123a
5689
ACC (8LK/REDI
Wire side ofterminals
ECM/PCM CONNECTORS
A (32P1
female
Wire side of {emale terminals
(From page 11-206)
Check for an open in the wite
IACC lino):Momentarily connect under_hood
luse/relay box 9P connector teF
minal No. 5 to body ground with
a jumper wire several times.
ls there a clicking noise from
the Iy'C compressor clutch?
S6e air conditioner insPoction
l3oa section 221ls there a clicking noise lrom
the ly'C compressor clutch?
Ropair open in tho wilo betwg€n
the ECM/PCM lA17) and the A/C
clutch rolay.
Chock for the oporation of lho
AIC:1, Start the engine.
2. Turn the blower switch ON
3. Turn the ray'C switch ON.
Check lor an open in the wiro(ACS lino):Measure voltage between ECM/
PCM connector terminals A27
and 820.
Does the Iy'C operate?
Air conditioning signal is OK.Repair op6n in the wiro bctwoon
lhe ECM/PCM lA27l and tho A/C
3witch.ls voltage lessthan 1.0 V?
- Sub6iitut€ r known€ood ECtt /PCM and rccheck. ll sYmP-
tom/indication 9oe3.waY,replaca the original ECM/PCM- See the ai. condhionGr in3p€c-tion lsee soc{ion 221.
11-207

Heater and Air Conditioning
Heater '.'..""" 21'1
Air Conditioning ......."'.. "' 22-1
SUPPLEMENTAL RESTRAINT SYSTEM (SRS}
The civic sRs includes a driver's airbag located in the steering wheel hub ln addition, all models (except some
models for canada) have a passenger's airbag located in the dashboard above the glove box'
Information necessary to safely service the sRS is included in this service Manual ltems marked with an asterisk (*)
on the contents page include, or are located near, sRs components. servicing, disassembling or replacing these
items will require special precautions and tools, and should therefore be done by an authorized Honda dealer'
@-";;il rendsring the SRS inoperative, which could lead to personal iniury or deaih in the svent of a sev€re
frontal collision. all SRS service work must be pertormed by an authorized Honda d€aler'
. lmploper service procedures, including incorrest removal and instsllation of the sRs, could lead to personal
iniury caused by unintentional deployment of the airbags'
o Do not bump the SRS unit. Otherwise. the system may fait in case of a collision. or the airbags may deploy
when the ignition switch is ON {ll}'
. sRs electrical wiring harncsses are id€ntified by yellow colol coding. Related components ale located in lhe
steering column, front console, dashboard, dashboald lowet panel, and in the dashboard above the glove box'
Do not use electricaltest equipment on these circuits.

Troubleshooting -'96 - 98 Models
Symptom Chart
NOTE;
. Check the engine coolant level. and allow the engine to warm up before troubleshooting.
. Any abnormality must be corrected before continuing the test.
. Because of the precise measurements needed. use a multimeter when testing.
o Before performing any troubleshooting procedures check:- Fuses No. 41 11.5 Al, No. 55 (40 A) in the under-hood fuse/relay box. and No. 17 (7.5 A) in the under-dash fuse/relay
box- Grounds No. G401, G402- Cleanliness and tightness of all connectors
SymptomRomedy
Hot air flow is low.Blower motor runs. but one or more
speeds are inoperative.
Perform the procedures in the flowchart (see page 21-8).
Blower runs properly.Check for the following:. Clogged heater duct. Clogged heater outlet. Incorrect door position
No hot air flow.Blower motor does not run at all,Perform the procedures in the flowchart (see page 21-10).
Blower motor runs.Check for the following:. Clogged heater duct. Clogged blower outlet. Clogged heater valve. Faultv air mix door. Heater valve cable adjustment (see page 21-44). Air mix control cable adiustment (see page 2'l-441. Faulty cooling system thermostat (see section 10). Clogged evaporator (with air conditioning). Frozen evaporator {with air conditioning)
Mode control motor does not run, or one or more modes
are inooerative.
Perform the procedures in the flowchart (see page 21-13).
Recirculation control door does not chanqe between
FRESH and RECIRCULATE.
Perform the procedu.es in the flowchan (see page 21-16).
Both heater and A,/C do not work.Perform the procedures in the flowchart (see page 21-18),
21-6

Blower Unit
Replacement
NOTE: The blower motor, recirculation control motor
and blower resistor can bs replacsd without rsmoving
th€ blower unit (see neld Page).
1. Move the temperature control to "HOT."
'96-98: Slide the temperature control lever.'99-00: Turn the ignition switch ON (ll), then turn
the temperature contol knob. Turn the ignition
switch off,
Remove the glovs box (ses ssction 20),
R€move ths s6lf-tapping screw and ths passsng6r's
dashboard low€r cover. Removo the bolt, the nut
and the kn€e bolst€r, then remove the fiv€ bolts and
the glove box trame,
Without Air Condhioning
4-a. Remove the wiro harness from the h68t€r duct, then
remove the two self-tapping scrsws and the heatsr
duct.
KNEE
GLOVE BOX FRAME
HEATER DUCT
21-37
Wrth Air Conditioning
4-b. Removo th6 ev8porator (sss pago 22-28).
6x1.0m|n9.8 N'm
6x1.0mm9.8 N'm lt'o tgf'm, t.2 lb{'ttl
Disconnoct the connectors trom th€ blower motor,
blowor r6sistor {'96 - 98 models), power transiator
('99 - 0O modsls), blowor motor high telay ('99 - 00
models) and recirculation control motor.
R€mov€ ths wiro harnoss clip from tho recirculation
control motor, and release the wir6 harnsss from ths
clamo on the blowor unit. Remove the two mount-
ing bolts, tho mounting nut and ths blowor unit'
9.8 .m 11.0 tgfm,1.2 tblfrl
lnstall in ths reverso order of removal. Mako surs
that thsre is no air leaka96.
6x1.0mm9,t N'm 11.0lgi.m,7.2 tbf.fil

Air Conditioning
Speciaf Tools ......'.....' 22-2
f f f ustrated f ndex ......................... ".......' 22-3
Wiring/Connector Locations'.........'.... 22'4
Description
Outfine ............ .......22-s
Circuit Diagram
'96 - 98 Models ......"..........".......'.... 22-6
'99 Modef """""""' 22-7
Troubleshooting
Symptom Chart ".'......""................. 22-8
Flowcharts
Condenser Fan .........".................,..'. 22-9
Compressor .....""" 22-12
A/C System .........'.22'17
A/C Thermostat
Test ........'.......' """'22'21
Relays
Test ....."'......... ..""'22-21
A/C Service Tips and Precautions ......22-22
A/C System Torque Specifications '...22-23
A/C System Service
Performance Test ... '."......... ".... ....'..22-24
Pressure Test Chart .................. .... "' 22-26
Recovery ...".........," 22-27
Evaporator
Replacement .....",' 22'24
Overhauf .....-.....""' 22'29
Compressor {SANDEN}
Repf acement ......'.' 22-30
fffustrated fndex ......"..................'.... 22'32
Cf utch Inspection ......... "............ ...... 22-33
Clutch Overhau I ........................ ....... 22-34
Thermal Protector Replacement .... 22-36
Relief Valve Replacement ......'..."". 22-36
Compressor (DENSO)
Repfacement ..""',' 22-37
lf lustrated Index ............................... 22-39
Clutch lnspection ............."'...... "'.... 22-40
Cf utch Overhaul .....................'......... 22-41
Ref ief Valve Replacement'..'......"'.. 22-42
A/C Compressor Belt
Adiustment ............22'43
Condenser
Repfacement .......,,22'44
A/C System Service
Evacuation ...,,,.......22-45
Charging '..........--'..22'46
Leak rest """""""'22-46