ECM HONDA CR-V 1998 RD1-RD3 / 1.G Manual PDF

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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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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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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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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'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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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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Alternator (ALT) FR Signal
This signals the ECM/PCM when the Alternator (ALTI is charging.
,97 modet: PCM GONNECTORS
wire side of female terminals
ALT CONNECTOR (C1O5I
lPr-F- ALT F
lll2llw|{frREDl|3.r-'l-
lruueen wne
c (31P|
wire side ol f€male terminals
PCM CONNECTOR C I31P)
3Pr
JUMPERWIRE
Inspection ot ALT FR Signal.
Check lor a short in the wire
{ALT F line}:1. Disconnect the 4P 13Pi* connector from the ALT.2. Turn the ignition switch ON (ll)
3, Measure voltage betweenPCM connector terminals C17
and A9.Check for a short in the wire(ALT F linel:1. Turn the ignition switch OFF.2. Disconnect the negative bat'tery cable from the battery.3. Disconnect PCM connector C(31P).
4. Check for continuity betweenbody ground and PCM connector terminal C17.
ls there approx. 5 V?
Check th€ ope.ation of the ALT:
1. Turn the ignition switch OFF2. Reconnect the ALT 4P {3Pi*connector to the ALT.3. Start the engine. Hold theengine at 3,000 rpm with no
load (in Park or neutral) untilthe radiator fan comes on,
then let it idle.4. Measure voltage betweenPCM connector terminals C17and A9.
Ropeir short in the wir6 betweonthe PCM lC17l and the ALT.
Substitut. a known-good PCM
and recheck. lf prescribed volt-
age is now availablo, replace the
originalPCM.
Does the voltage decrease when
headlights and rear defogger are
turned on?ALT FR signal b OK.
Ch€d( for an op€n in tho wire IALTF linel:1. Turn the ignition switch OFF.2. Disconnect the negative bat-tery cable lrom the battery.3. Disconnect PCM connector C(31P).
4. Disconnect the 4P (3P)* con-nector lrom the ALT.5. Connect the ALT 4P (3P)* con-nector terminal No. 4 (No. 1)*to body ground with a iumper
6. Check for continuity betweenbody ground and PCN4 con'nector terminal Cl7.
Repair open wi.e between thePCM lCl7l and the ALT.ls there continuity?
ALT F IWHT/REDI
Wire side of female terminals
1 1-159
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ldle Gontrol System
Alternator (ALT) FR Signal (cont'dl
'98 - 00 modols:
ALT CONNECTOR (C1I}5I
4P
rH] Arr Fl'l'ltwHr/REo)l3laF1
I JUMPER WIRE JUMPER+ WIRE
ECM/PCM CONNECTORS
Wire side of female terminals
ECM/PCM CONNECTOR C {31PI
Wire side of female terminals
Wire side of female terminals
ECM/PCM CONNECTOR C {31P}
": Canada
1 1-160
B (25P)
Insp€ction of ALT FR Signsl.
Check fo. a shon in th. wire {ALTF linel:1. Disconn6ct the 4P (3P)* con-nector from the ALT.2. Turn the ignition switch ON {ll).3. Measure voltage between ECM/PCM connector terminals C5and 820.Ch€ck for a sho.t in iho wirc lAlTF lino):1. Turn the ignition switch OFF.2. Disconnecl the negative bat,tery cable from the battery.3. Disconnect ECM,PCM connec-torC (31P).
4. Check for continuity betwoenbody ground and ECM/PCMconnector terminal c5.
ls there approx. 5 V7
Check the opcration of the ALT:1. Turn the ignitioo switch OFF.2. Reconnect rhe ALT 4P (3P)*connector to the ALT.3. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator lan comes on,then let it idle.4. Measure voltage between ECM/PCM connector terminals C5and 820.
Roprir lhort in tho wirc bstweentho ECM/PCM {Csl and the ALT.
Substitut. r known-good ECM/PCM and roch.ck. It Droscrib.dvoltage b now lvrilabls, .eplaccth. o.igin!l ECM/PCM.
Does the voltage decrease whenheadlights and rear defogger areturned on?ALT FR 3ignol is OK,
Chock lor an opon in tha wire (ALTF linel:1. Turn the ignition switch OFF.2. Disconnect the negative bat-tery cable from the battery.3. Disconnect ECM/PCM con-nector C (31P).4. Disconnect the 4P 13P)* con,nector from the ALT.5. Connect the ALT 4P {3P)* con-nector terminal No. 4 1No. 1)*to body ground with a jumper
6. Check for continuity betwe€nbody ground and ECM/PCMconnector terminal C5.
Rsprir opan wiro batw.en thoECM/PCM lcsl .nd th. ALT.ls there continuity?
AI.T F IWHT/REDI
ALT F {WHT/REDI
Wire side ot Iemale terminals
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Starter Switch Signal
This signals the ECM/PCM when the engine is cranking.
'97 model:
A {32P}
'98 - 00 models:
Transmission in E or E position.
LGl(BBN/BLK)
PCM CONNECTORS
Wire side of female terminals
ECM/PCM CONI{ECTORS
STS (BLU/ORNI
c t31P)
NOTE:. M/T: Clutch pedal must be depressed.. A/T: Transmission in E orE position
Check for an opan ot short in the
wire (STS linel:Measure voltage between PCM
connector terminals C6 and Ag
with the ignition switch in the
start (lll) position.
lnspect the No. 31 STARTER SIG-
NAL (7.5 A)Illse in the under'dashls there battery voltage?- Reoair short in the wire be-
tween the PCM lc6l and th.No. 31 STARTER SIGNAL 17 5A) tuse ot the PGM-FI main
reray.- Reolace the No. 31 STARTERSIGNAL t7.5 Altu.e.
Starter swiich signal i3 OK.
Repair opon in the wire betweonrh6 PCM lc6l and the No 31
STARTER SIGNAL 17.5 A)fuse.
A (32P)
Wire side oI female terminals
Check tor an open or short in thewir€ (STS line):Measure voltage between ECM/
PCM connector terminals A24
and 820 with the ignition switchin the start position (lll).
Inspect the No. 31 STARTER SIGNAL (7.5 A){use in the under-dashls there battery voltage?
- Reoair shorl in the wire
betwe€n the ECM/PCM lA2,fland the No, 31 STARTER SIG-NAL t7.5 Al tu3€ ot the PGM'Fl main rclay.- Repl.c. tho No. 31 STARTERSIGNAL 17.5 Al fu3e.
Starter switch 3ignal is OK.
Repair opon in tho wire between
the ECM/PCM {A241 and the No
31 STARTER SIGNAL (7.5 A) tu3e
1 1-161
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ldle Gontrol System
Power Steering Pressure (PSP) Switch Signal
This signals the ECM/PCM when the power steering load is high.
'97 model:
*: Do not hold the steering wheel at tulllock for more than five seconds,
Wire side of female terminals
PSP SWTTCH 2P CONNECTOR 1C135)
PSP SW (GRN)
JUMPER T_7 1 \vnRE t--f r)
GND IBLK}
Wire 3id6 of female terminals
Inspection ot PSP switch signal.
Check for an open in the wire {PSPSYV line):1. Turn the ignition switch ON (ll).2. Measure voltage betweenPCN4 connector terminals C16and A9.
Check tor an open in lhe wire (PSPSW linel:1. Turn the ignition switch OFF.2. Disconnect the PSP switch 2Pconnecror,3. Turn the ignition switch ON (ll).4. At the harness side, connectthe PSP switch 2P connectorterminals No. 1 and No. 2with a jumper wire.5, Measute voltage betweenPCM connector terminals C16and A9.
ls there less than 1.0 V?
- Ropsir open in the wi.e be-twoon the PCM lcl6l and thePSP switch.- Ropdir open in BLK wire be-tween the PSP switch andG101.
ls there less than 1.0 V?Check the operation oI lhe PSPswitch:1. Stan the engine2. Turn the steering wheelto thefull lock position*.
3. Measure voltage between PCMconnector terminals C16 andA9.
ls there battery voltage?
PSP switch signal is OK.(To page 11-163)
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