IAC HONDA CR-V 1999 RD1-RD3 / 1.G Owner's Manual
[x] Cancel search | Manufacturer: HONDA, Model Year: 1999, Model line: CR-V, Model: HONDA CR-V 1999 RD1-RD3 / 1.GPages: 1395, PDF Size: 35.62 MB
Page 351 of 1395
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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Page 352 of 1395
ldle Control System
ldle Control System
I P0505 | The scan tool indicates Diagnostic T.ouble Code (DTCI PO5O5: ldlecontrol svstem mattunction.
NOTE: lf DTC P1508 is stored at the same time as DTC P0505, troubleshoot DTC P1508 first. then troubleshoot DTC p0505.
Possibls Cause
. IAC valve mechanical malfunction. Throttle body clogged port, improper adlustment. Intake manifold gasket leakaging. Intake air hose loose leakaging. Vacuum hose leakaging
a ECT sensor incorrect output. Throttle Position sensor incorrect output
Troubleshooting Flowchart
The MIL has been reDorted on.DTC P0505 is sto.ed.
Problem verificationi1. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator Ian comes on, thenlet it idle.2. With the scan tool, check thelollowing items.- Throttle position should beapprox. 10% with the throt-tle {ully closed.- Engine coolant temperature shorJld be 194 - 205'F(90 - 96"C).lf they are not within thespec., repair the faulty sen-sor circuit.3 Check the engine speed atidle with no-load conditions:headlights, blower fan. reardefogger, radiator lan, and airconditioner are not operaling,
Inte.mittent failure. syltem is OKat this time.ls it 750 {730)* i 50 rpm?
ls il 700 (680)' rpm or less?
{To page 11-151)(To page 1'l-151)
l:'99 - 00 models
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Page 353 of 1395
(From page 11-150)
{From page 11-150}
THERMO VALVE(A/T onlyl
Check the IAC valve:Disconnect the 2P connector from
the IAC valve.
Does the engine speed droP
or the engine stall?
Adiust the (basel idl€ speed lseepage 11-169, 1t0). Itihe ba3e idle
speed cannot be adiust€d, clean
the Dorts in the throttle body.
UPPER
Check the tast idle lhermo valve:
1. Turn the ignition switch OFF.
2. Remove the intake air ductfrom the throttle body.3. Start the engine and let it idle.
4. Put your finger on the lowerpon in the throttle body.
Check engine cool.nt level and for
air in the cooling sy3lem. lf OK,
reolace the f.st idle thermo valve.Does the engine speed drop?
Put your Iinger on the uPPer Portin the throttle body.
Check for vacuum leaks, make
sure the throttle valve is com'pletely clo3ed. and repair as nec-Does the engine speed droP?
Adjust the idle spoed lsee Page11-169. 1701. lf the adiustmentdoes not correct lhe problem,
r.olace the IAC valve.
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Page 354 of 1395
ldle Control System
ldle Air Control llAC) Valve
The scan tool indicates Diagnostic Trouble Code (DTC) Pl508: A probtem in the ldle Air Controt flAC) varvecircuit.
The IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the ECM/PCM inorder to maintain the proper idle speed.
37 model;
IAC VALVE 2P CONNECTOR {C132}
,f rcp'# IYEL/BI.(II2f-1-d)
Y
Wir€ side of female terminals
PCM CONNECTOR A I32PI
tacvIBLK/BLU)
From AIR To INTAKECLEANER MANIFOLD
Wire side of female terminals
The MIL has beon .eport€d on.OIC Pl508 is sto.ed.
Problem veiification:1. Do the PCM Reset Procedure.2. Start the engine, and warm itup to normal operating tem-perature.
Inte.mittent failure, systcm b OKat thi3 time. Check tor poo. con-nections or loose wircs at C132(lAC v.lvel and at the PCM.
ls DTC Pl508 indicated?
Check lor an open in the wir6{lGPl lins}: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 2Pconnector term inal No.2.
Repair open in the wire trctwoontha IAC v!lv6 and the PGM-Flmain relly.
Chock for an opan o. short in thowi.e (lACv linel:1. Turn the ignition switch OFFand reconnect the IAC valve2P connector.2. Disconnect the PCM conneclorA (32P).
3. Turn the ignition switch ON {ll).4, Measure voltage betweenbody ground and PCM con-nector terminal A12.
{To page 1l-153)
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Page 355 of 1395
Bepair op€n or short in the wire
betweon th€ PCM {A121 and the
IAC vrlve.ls there baftery voltage?
Check the IAC valve function:Momentarily connect PCM con'nector terminals A12 and A10with a iumoer wire severaltimes,
Does the IAC valve click?
Substitute . known-good PCM
and r€check, lt 3ymptom/indica-tion goes away, replaco the origi_nalPCM,
(From page 11-152)
Wire side of female terminals
1-153
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Page 356 of 1395
The MIL has boen r.ported on.DIC Pl 508 b 3tored.
Problem veritication:L Do the ECM/PCM Reset Pro-cedure.2. Start the engine, and warm itup to normal operating tem-perature.
Int€rmittent failure, systom is OKal lhis timo. Check lor poor con-nections or looro wirca at C132(lAc vrlvel and .t rho EcM/PcM.
ls DTC P1508 indicated?
Chock tor an open in the wir6llGPl linel: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 2Pcon nector termina I No, 2.
Repair opon in the wira botwoonthe IAC valve and tho PGM-FImain aalay.
Check tor an open or short in thewire (IACV linel:1. Turn the ignition switch OFFand reconnect the IAC valve2P connector.2. Disconnect ECM/PCM con-nector B {25P).3. Turn the ignition switch ON {ll}.4. Measure voltage betweenbody ground and ECM/PCMconnector terminal 823.
Ropair open or short in thg wirebetween tho ECM/FCM lB23l andthe IAC valve.
ls there battery voltage?
Check the IAC valve func,tion:Momentarily connect ECM/PCMconnector terminals 823 and 82with a jumper wire several times.
Does the IAC valve click?
Subslitute . known-good ECM/PCM .nd rechock. lf symptom/indication goes aw.y, replac.th€ original ECM/PCM.
ldle Air Control (lAC) Valve {cont'd}
'98 - 00 models:
IAC VALVE 2P CONNECTOR {C132I
F rcpt*l tYELrBLxlI2/'-- rf)
Y
Wire side ot fem.le terminals
ECM/PCM CONNECTOR B (25PI
Wire side of female torminals
258
9'to1l13t7
1920212223
tAcv(BLK/BLUIv
PG1{BLKI
12 | t3 4 58
910 111317
1920 | 121)22
tAcv(BLK/
BLU)JUMPER WIRE
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Page 359 of 1395
'98 - 00 models:ECM/PCM CONNECTORS
ECM/PCM CONNECTOR A (32PI
Wire side of female terminals
ECM/PCM CONNECTORS
A (32P1
ACC (BLK/REOI
LG1 (BRN/BLKI
{cont'd)
11-157
A {32P1
Check for a shott in the wire
{ACS linel:1. Turn the ignition switch OFF.
2. Disconnect the A/C Pressureswitch 2P connector.3. Turn the ignition switch ON (ll)
4. Measure vo ltage betweenECM/PCM connector terml
nals A27 and 820.
Check tor . short in the wire IACSlinel:1. Turn the ignition switch OFF.
2. Disconnect ECM/PCM connec-tor A (32P).
3. Check for continuity betweenbody ground and ECM/PCMconnector terminal A27.
ls there battery voltage?
R.oak short in the wile between
rhe ECM/PCM (A271 and the A/C
Dressure switch.ls there continuitv?
Sub6titute a known{ood ECM/
rcM and recheck. lf pte6cribed
voltage i3 now available, re'pl.ce the origioal ECM/rcM.See ih6 air conditioner inspec-
tion (s6e section 221.
Check for an open in the wire(ACC line):'1. Turn the ignition switch OFF.
2. Reconnect the A/C Pressureswitch 2P conneclor.3. Turn the ignition switch ON (ll).
4. Momentarily connect ECM/PCM connector terminals A17
and 820 with a jumPer wireseveralllmes,
{To page 11 158)JUMPER WIRE
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Page 360 of 1395
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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Page 371 of 1395
ldle Speed Setting
Inspoction/Adiustmont
37 modsl:
NOTE:
. Before setting the idle speed, check the following
items:- The MIL has not been reportsd on.- lgnition timing- Spark plugs
- Air cleaner- PCV system
. lcanada) Pull the parking brake lever up. Stan the
engine, then check that the headlights are off.
1. Start the engine. Hold the engine at 3,000 rpm with
no load (in Park or neutral) until the radiator fan
comes on, then let it idle.
Connect a tachometer or a Honda PGM Tester.
Disconnect the 2P connector from the ldle Air Con-
trol (lAC) valve.
IAC VALVE
lf the engine stalls, restart the engine with the accel-
erator pedal slightly depr6ss6d, Stabilize the rpm at
1,000, then slowly release the pedal until the engine
idles.
Check idling in no-load conditions: hsadlights,
blower fan, rear d€fogger, radiator fan, and air con-
ditioner are not operating.
ldle spood should b.:
{80 t 50 rpm {in Park or noutr.ll
IDLE
7.
Adjust the idle sp6ed,
idle adjusting screw.
if necessary, by turning the
Turn the ignition switch OFF.
Reconnect the 2P connector to the IAC valve, then
remove the BACK UP (RAD|Ol (7.5 Al fuse in the
under-hood fuse/rslav box for 10 seconds to reset
the PCM.
Restart and let the engine idle with no-load condi-
tions for one minute, then check the idle speed.
NOTE: (Canadal Pullthe parking brake lever up. Stan
the engine, then check that the headlights are off.
ldlo Ep€ed rhould be:
75O t 50 rpm (in P.rk or noutr.ll
Let the engine idl6 for one minute with the head-
lights (Low) ON, and check th€ idl€ speed.
ldle lpcod 3hould bo:
750 t 50 ]pm (in Park or nautlal)
Turn the headlights off. Let th€ engine idle for one
minute with the headlights (Low) ON, heater fan
switch at Hl and air conditioner on. then check the idle
sDeeo.
ldl. specd should b6:
7d) 1 50 rpm {in Park or nautral}
lf the idle speed is not within specification, see the
symptom chart on page 11-64. (cont'd)
1 1-169
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Page 372 of 1395
ldle Control System
ldle Speed Setting (cont'd)
38 - 0O mod6l3:
NOTE: Before setting the idle speed, check the follow-
ing items:- The MIL has not been reported on.- lgnition timing- Spark plugs
- Air cleaner- PCV system
1. Start the engine. Hold the engine at 3.000 rpm with
no load (in Park or neutral) until the radiator fan
comes on, then let it idle.
Connect a tachometer.
Disconnect the IAC valve 2P connector and the EVAP
purge control solenoid valve 2P connector.
CONTROLSOLENOID VALVE
SOLENOID VALVE
lf the engine stalls, restart the engine with the accel-
erato. pedal slightly depressed. Stabilize the rpm at
1,000, then slowly release the pedal until the engine
idles.
Che€k the idle in no-load conditions: headlights, blow-
er fan, rear defogger, radiator fan, and air conditioner
are not operating,
ldle speed should bo:
480 t 50 rpm {in PErk or noutrall
11-170
lf necessary, adjust the idle speed, by turning the
idle adjusting screw.
After adjusting the idle speed, recheck the ignition
timing (see section 4). lf it is out of spec, go back to
steo 4.tDt.E
6. Turn the ignition switch OFF.
7. Reconnect the 2P connectors to the IAC valve and
the EVAP purge control solenoid valve, then do the
ECM/PCM reset procedure.
8. Restart and idle the engine with no-load conditions
for one minute, then check the idle speed.
ldle speod should be:,98 model:
750 t 50 rpm tin Park or neutral)'9!l - 00 modsls:
730 i 50 lpm lin Psrk or neutral)
NOTE: lf the idle speed increases to 780 t 50 rpm(770 1 50 rpml*, this means the EVAP system is
purging the canister. To stop the purging temporari-
ly, raise the engine speed above 1,000 rpm with the
accelerator pedal, then slowly release the pedal.*: '99 - 00 models
9. Let the engine idle for one minute with the head-
lights (Low) ON, and check the idle speed.
ldle speed should be:
38 mod6l:
750 f 50 rpm (in Palk or neutrall'99 - 00 modols:
730 t 50 rpm (in Palk or neutral)
10. Turn the headlights off. Let the engine idle for one
minute with the heater fan switch at Hl and air con-
ditioner on, then check the idle speed.
ldls spqed should be:'98 model:
780 t 50 rpm (in Park or neutrall'99 - 00 mod€ls:
7701 50 rpm lin Park or neutral)
lf the idle speed is not within specification. see the
Symptom Chart on page 11-64.
ADJUSTING
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