1997 HONDA CR-V Air conditioning

PGM-FI System
System Description
INPUTS
CKP/TDC/CYP Sensor
CKF Sensor
MAP Sensor
ECT Sensor
IAT Sensor
TP Sensor
Primary HO2S
Secondary H02S
vss
KS*5
BARO Sensor
ELD*6
Starter Signal
ALT FR Signal
Air Conditioning Signal
Ay'T Gear Position Signal*1
Baftery Voltage (lGN.1)
Brake Switch Signal
PSP Switch Signal
Fuel Tank Pressuae Sensor*4. *5
Countershaft Speed Sensor*1
Mainshaft Speed Sensor*r
OVER-DRIVE Switch Signal*s
ENGINE CONTROL MODULE (ECM)/
POWERTRAIN CONTROL MODULE (PCM) OUTPUTS
|iuel 1"j""- Th,rhg ""d Drrafr";-l
Et*-.nt"tdt"cont.orl
to,r*,c;;trffi;]
l.----.---:. .Lrgnrnon |lmrng Lonrror I
Ecir/PcM B*k',p Fr""il]
m;"t-ll-r*'io*l
Fuel Injectors
PGM-Fl Main Relay (Fuel Pump)
MIL
IAC Valve
Ay'C Compressor Clutch Relay
Radiator Fan Relay
Condenser Fan Relay
ALT
tcM
EVAP Purge Control Solenoid
Valve
Primary HO2S Heater
Secondary H02S HeaterEVAP Bypass Solenoid Valve*a *5
EVAP Control Canister Vent Shut
DLC
Lock-up Control Solenoid Valve*l
Shift Control Solenoid Valve*1
Ay'T Clutch Pressure Control
Solenoid Valve*1
D4 Indicator Light'1 *3, *a
D Indicator Light,l *5
OVER-DRIVE OFF Indicator
Lighl*t *:
*1: A/T {3:'97 model'2: M/f +4:'98 model*5: '99 - 00 models"6: USA
PGM-Fl System
The PGM-Fl system on this model is a sequential multiport fuel injection system.
Fuel iniecior Timing and Duration
The ECM/PCM contains memories for the basic discharge durations at various engine speeds and manifold pressure. The
basic discharge duration, after being read out from the memory, is further modified by signals sent from various sensors
to obtain the final discharge duration.
ldle Air Control
ldle Air Control Valve (lAC Valve)
When the engine is cold, the Ay'C compressor is on, the transmission is in gear, the brake pedal is depressed, the P/S load
is high, or the alternator is charging, the ECM/PCM controls current to the IAC Valve to maintain the correct idle speed.
lgnition Timing Control
o The ECM/PCM contains memories for basic ionition timing at various engine speeds and manifold air flow rates.
lgnition timing is also adjusted for engine coolant temperature.
. A knock control system was adopted which sets the ideal ig nition timing for the octane rating of the gasoline used.*s
Other Control Funstions
1. Starting Control
When the engine is started. the ECM/PCM provides a rich mixture by increasing fuel injector duration.
2. Fuel Pump Control
. When the ignition switch is initially turned on (ll). the ECMiPCM suppli€s ground to the PGM-FI main relay that
supplies current to the fuel pump for two seconds to pressurize the fuel system.
. When the engine is running, the ECM/PCM supplies ground to the PGM-FI main relay that supplies current to the
fuel oumo.
. When the engine is not running and the ignition is on, the ECM/PCM cuts ground to the PGM-FI main relay which
cuts current to the fuel pump.
1 1-80
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Fuel Cut-off Control
. During deceleration with the throttle valve closed, current to the fuel injectors iscutoffto improvefuel economyat
speeds over 970 rpm ('97 - 98 models), 920 rpm ('99 - 00 modelsl.
. Fuel cut-off action also takes place when engine speed exceeds 6,500 rpm ('97 - 98 models), 6900 rpm ('99 - 00
models), regardless of the position of the throttle valve, to protect the engine from over-rewing.
With Ay'T model. the PCM cuts the fuel at engine speeds over 5,000 rpm when the vehicle is not moving.*'
4,./C Comoressor Clutch Relav
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 a smooth transition to the Ay'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,
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.
PCM Fail-saf e/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-pre
grammed value for that sensor that allows the engine to continue to run.
2. Back-up 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 IMalfunction Indicator Lamp (MlL)l
When an abnormality occurs in a signal from a sensor, the ECM/PCM supplies ground for the MIL and stores the DTC
in erasable memory. When the ignition is initially turned on {ll), the ECM/PCM supplies ground for the MIL for two
seconds to check the MIL bulb condition.
4. Two Trio Detection Method
To prevent false indications, the Two Trip Detection Method is used for the HO2S*1, fuel metering-related. idle control
system, ECT sensor 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 (ll) 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 {'97 model)
A "Driving Cycle" consists of starting the engine, beginning closed loop operation, and stopping the engine. lf misfir-
ing that increases emissions or EVAP control system malfunction is detected during two consecutive driving cycles.
or TWC deterioration is detected during 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.
*1: '97 - 98 models*2: '99 - 00 models
5.
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ldle Control System
System Description
The idle speed of the engjne is controlled by the ldle Air Control (lAC) Valve'
The valve changes the amount of air bypassing into the intake manifold in response to electric current controlled by the
ECM/PCM. When the lAc valve is activated, the valve opens to maintain the proper idle speed.
YEL/ From PGM'FI
BLK TMAIN RELAY
VARIOUSSENSORS
4.
IAC VALVE
INTAKE MANIFOLD
After the engine starts, the IAC valve opens for a certain time. The amount of air is increased to raise the idle speed
about 150 - 300 rpm.
when the cootant temperature ts row, the lAc valve is opened to obtain the proper fast idle speed The amount o{
bvoassed air is thus controlled in relation to the engine coolant temperature
When the idle speed is out o{ specification and the scan tool does not indicate Diagnostic Trouble Code (DTC) P0505
or P1508, check the following items:
. Adjust the idle speed (see page 11-169, 170)
. Air conditioning signal (seepagell-1551
. ALT FR signal (see page 1l-159)
. Starter switch signal (see page 11-16'1)
. A,/T gear position signal (see section 14)
. PSP switch signal (seepagell-162)
. Brake switch signal (see page 11-165)
. Fast idlethermovalve (see page'11 168)
. Hoses and connecttons. IAC valve and its mounting O-rings
lf the above items are normat, suDslitute a known-good IAC valve and readjust the idle speed {see page 11-169, 170)
lf the idle speed still cannot be adjusted to specification (and the scan tool does not indicate DTC P0505 or Pl508)
after IAC valve reolacement, substitute a known-good ECM/PCM and recheck lf symptom goes away' replace the
original ECM/PCM.
11-149
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Air Conditioning Signal
This signals the EcM/PcM when there is a demand for cooling from the air conditioning system.
'97 modol:
Wire side of lemale terminals
PCM CONNECTOR C (31PI
ACS IBLU/RED)
PCM CONNECTOR A (:TIPI
(cont'd)
1 1-1 55
Chock for a shorl in thc wiro(ACS linol:1. Turn the ignition switch OFF.2. Disconnect the A/C pressure
switch 2Pconneclor.3. Turn the ignition switch ON (ll).,1. [Ieasu re voltage betweenPCM connector terminals C5
and A9.
Check for . .hon in the wire IAGSlinel:1. Turn the ignition switch OFF.2. Disconnect PCM connector C(31P).
3. Check for continuity betweenbody ground and PCM con-nector torminal C5.
Reoaii short in tho wire b€twoenrh6 PCM (Csl and the A/C pres-
3urc 3witch.
- Subcdtrte a known{ood PCMand recheck. lf pr6actibed volt-age is now av{ilable, roplacethe origind PCM,- Soe the eir conditionor in3p€c-lion lsee soction 221.
Check tor an opon in the wite(ACC lino):1. TLrrn the ignition switch OFF.2. Roconnect the A/C pressure
switch 2P connector.3. Turn the ignition switch ON (ll).
4. Momenta rily connect PCMconnector terminals A9 and417 with a iumper wire sev'eraltimes,
Wire side of female terminals
JUMPER WIRE
(To page 11-156)Wire side oI Iemale terminals
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ldle Gontrol System
Air Conditioning Signal (cont'dl
(From page 11-'155)
JUMPERWIRE
UNOER.HOOD FUSE/RELAYBOX 9P CONNECTOR tqt52)
123I
56I
ACC IBLK/RWire side ofACC IBLK/REDIWire side of femaletermrnats
A t32PlPCM CONNECTORS C t3rp)
Wire side ol lemale terminals
Ch6ck for an open in th€ wire(ACC linel:Momentarily connect the under-hood fuse/relay box 9P connectorterminal No.5 to body groundwith a jumper wire several times.
ls there a cl;cking noise fromthe 4!/C compressor clutch?
ls there a clicking noise fromthe 4!/C compressor clutch?See air condiiioner inspection{see section 221.
Repai. op6n in the wire betwoenthe PcM (A17) and tho A/Cclutch relay.
Check the A/C operation:1. Start the engine.2. Turn the blower switch ON.3. Turn the A"/C switch ON.
Check for an open in the wire(ACS line):Measure voltage between PCMconnector terminals Ag and C5.
Does the A,/C operate?
Air conditioning signal is OK.
Repair open in the wire betweenthe PCM lCSl and the A/C awitch.ls there less than 1.0 V?
- Subqtitute a known-good FCM.nd r€ch6ck. lt 3ymptom/indi-cation goes awav, replece theoriginal rcM.- Soe th€ eir conditioner in3pec-tion (s6€ aec.tion 22).
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ldle Control System
Air Gonditioning Signal (cont'd)
JUMPERWIRE
UNDER-HOOD FUSE/RELAYBOX 9P CONNECTOR {G'52I
23a
5589
ACC (BLK/R
Wire side otACC (BLK/RED'
Wire side otfemaleterminals
ECM/PCM CONNECTORS
Wire sid€ of female torminals
(From page '11,157)
Check Ior dn opon in the wiroIACC linel:Momentarily connect the under-hood fuse/relay box 9P connectorterminal No. 5 to body groundwith a jumper wire several times.
ls there a clicking noise lromthe y'y'C compressor clutch?
ls there a clicking noise fromtho A,/C comprossor clutch?Sae rir conditional in3pactionlroa saction 221.
Repai. open in th6 wiro lr€twlanthe ECM/PCM lAl7l .nd tho A/Cclutch rolay.
Check tho op.ration of tho A/C:1. Stan the engine.2. Turn the blower switch ON.3. Turn the Ay'C switch ON.
ChGGk for an open in the wi.eIACS linel:Measure voltage betweon ECM/PCM connector terminals A27and 820.
Does the !y'C operate?
Air conditioning 3ignal i3 OK.
Rap.ir opon in the wir6 bdtunaanrh. Ecil/FcM lA27l rnd rh. A/crwitch.
ls voltage less than 1.0 V?
Sub6lftna a known{ood ECM/PCM and rechock. lf symp-tom/indicetion goes away.roplace the original ECM/rcM.See the ah conditionor inspoc-tion {3e€ section 22},
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a
Heater and Air Conditioning
Heater ...........21
NOTE: Section 21 ("Heater") is included in section 22.
Air Conditioning ......'..'.. '.'22'1
SUPPLEMENTAL RESTRAINT SYSTEM (SRS}
This model has an SRS which includes a driver's airbag in the steering wheel hub, a passenger's airbag in the dashboard
above the glove box ('97,00 models). and seat belt tensioners in the seat belt retractors ('98 - 00 models). 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 only be done by an authorized Honda dealer.
@. To avoid rendering the SRS inoperative, which could lead to personal iniury or death in the event of 8 severe frontal
collision, all SRS service work must be performed by an authotized Honda dealer.
lmproper service procedures, including incorrect removal and installation of the SRS, could lead to personal iniury
caused by unintentional deployment of the airbags ('97 - 00 models), and seat belt tensioners 138 - 00 models).
Do not bump the SRS unit. Otherwise, the system may fail in case of a collision, or the airbags may deploy when the
ignition switch is ON {lll.
SRS eleqtrical wiring harnesses are identified by yellow color coding. Related components are located in the steering
column, front console, dashboard, dashboard lower panel, and in the dashboard above the glove box. Do not use elec-
tricaltest equipment on thes€ cilcuils.
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Air Conditioning
Heater Control Panel
Reofacement ,.,...,,.,..,.,.,,22-46
Blower Unit
Replacement .................. 22-46
Overhaul ...........,,,., .......-.22-17
Evaporalor
ReDlacement ...,.,.,..,......,22-4A
Overhaul ................ .........22-19
A/C Filter
Replacement ..................22-50*Heater Unit
ReDfacement ..................22-50
Overhaul ..,.,..,.,...,.. .........22-52
Temperature Control
Adiustment ....................22-53
A/C Service Tips and Precauiions............-....-.... 22-54
A/C System Torque Specifications .................... 22-55
A/C System Service
Performance Test ......,...22-56
Pressure Test Chart .-.....22-5a
Recovery ..............,. ...-.-...22-59
Evacuation -...........-........22-60
Charging ................ .......-.22-61
Leak Test ........................22-61
Compressor
Repfacement ..........-.......22-62
flfustrated Index .....,.......22-64
Cfutch fnspection .........,.22-65
Cfutch Overhaul ............- 22-66
Thermaf Protector Rep|acement ................... 22-68
Refief Valve Replacement .............................. 22-68
A/C Comoressor Belt
Adiustment .................... 22-69
Condenser
Repfacement .,.....,,.,..,.,..22-70
'Read SRS precautions betore working in this area.
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