1994 HONDA INTEGRA Ecm

System Description
The idle speed ot lhe engine is controlled by the ldle Air Control {lAC) Valve.
The valve changes the amount ot air bypassing into the intake manifold in response to electric current controlled by the
ECM. When the IAC Valve is activated, the valve opens to maintain the proper idle speed.
#l' ----rTo FGM-FIMAINRELAY
VARIOUSSENSORS
IAC VALVE
FASTIDLETHERMOVALVE
INTAKE MAI{IFOLD
(cont'd)
BLK
r
11-79

1. when the idls speed is out of specification and the Malfunction Indicator Lamp (MlLldoes not blink Diagnostic Trou-
ble Code (DTC) 14, check the tollowing items:. Adiust the idle speed {see page I1-95). Air conditioning signal (see page l1-84). ALT FR signal (see page '11-86)
A/T gea, position signal (see page 11-88)
Erake switch signal (see page 1 1-90)
Starter switch signal (see page 1l-921
PSP switch signal (see page 1 1-93)
Fast idl6 thormo valve (see page l1-94)
Hoses and connsctions
IAC valve and its mounting O-rings
2. lf the above items are normal, substitute a known-good IAC vslv€ and readjust the idle speed (see page 11-95)'
. It the idle speed srill cannot be adjusted to speciJication (and the MIL does not blink code 14) after IAC valve
roplacement, substitute a known-good ECM and recheck. It symptom goes away, replsce the original ECM.
1 1-81

ldle Control System
ldle Air Control (lACl Valve
lt6l- -l lf l- The Maltunction Indicator Lamp (MlL) indicates Diagnostic Trouble Code {DTC} 14: A problem in
' '- the ldle Air Control llAC) Valve circuit.
The IAC Valve changes the amount of air bypasEing the throttle body in respons€ to a current signal from the ECM in
order to maintain the proper idle speed.
ffi: r;611/ | /--T-\
- The MIL h.3 been report don,- With tho SCS shon connoctolconnoctod (soo pago 'l 'l -341,
cod6 14 is indicatod.
Do the ECM Reset Procedure (seepage 11-35).
With the engine running snd theaccelerator pedal releas€d, dis-conn€ct th€ 2P connector frorttho IAC valvo.
ls the MIL on and does it indicatecode 14?
htarmitlaot frlu]., aya-t.m i. OK !t thir tlft.
ll.rl drlv. mly ba nac-aaaaryl.Chack tor Doo. conn€c-tlonr oi loora wirca atC3O5 (loc.t.d .t |.ftlhock tow.tl, C424,Cl tB (lAC v.lvol .ndECM.
Disconnect the 2P connector fromthe IAC valve.
Sub.iituto . known{ood IACvdva lnd iotolt.
{To page 11-83}
11-82

(From page 'l 1-82)
Measure voltago between theYEL/BLK wire and bodv ground.
R.pair op.n In YEL/8LK who b.-twoon IAC vCvc dd PGM-FI mdnrelay.ls th€rs battery voltage?
Turn th€ ignition swirch ott andreconnect thg 2P cohnector to theIAC valve.
Conn€ct the test hs.ness "A"
connector to the main wirs hrr-n6ss only, not the ECM lsee page
t 1-37).
Tu.n tho ignition switch ON.
Momentarily connect Ag torminalto 423 terminol seveaal tim€s.
Sub.titutr ! known{ood ECM.nd ral..t. lt .ymptom/hdlcatioogoa! awsy. rophca tia origlnalECM.
Does th6 IAC valve click?
Raplir op.n or rhort in 8LK/BLUwl]. b.tw.cn IAC v!lv..nd ECM(A91, It th. wlro L OK, r.Dhc.lheIAC v.lv..
IAC VALVEBLK/BLU { _ }
JUMPER WIRE
A9 l+) A23 {-l
1 1-83

ldle Gontrol System
Air Conditioning Signal
This signals the ECM when there is a demand for cooling from the air conditioning system.
Connect the t€st harness betweenthe ECM and connectors. Discon-nect "B" connector from the mainwire harness onlv, not the ECM{see page 11-37}.
Turn the ignition switch ON.
Measure voltage between 851+ )lerminal and A26 l- I terrninal.
Sub.litut ! known{ood €CMrnd r6 ls there approx. 5 V?
Turn th€ ignition switch OFF.
Reconnect "8" connector to themain wire harness.
Turn the ignilion switch ON.
Momentarilv connect A15 termi-nalto A26 terminsl severaltimes.
Momsntarilv connect the 8LK/RED t€rminal of the 4P connectoron the A/C clutch rel6v to bodyground sevsral times.
ls there a clicking noise fromthe A/C comDressor clutch?
3o6 rlr condhlohar in-rDactlon llaa lac{ion221.
ls there a clicking nois€ lromth€ A/C comoressor clutch?
Rop.ir opon in BLK/BED wiro be-two.n ECM {A15} and A/C clurchrally.
ooooooooooooo
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ooooooooooo
.pprox. 5 V?
426 (- )
Cllcklng?
lTo page
11-84
-

(From page 11-84)
Does A/C operate?
Aii coiditiodlng slgnal i! OK.
r-Less than 1.0 V? -----------.1
I 85 {+l
|----------------I| | ooooooooooooe loooooooo 1t)6i}66i)l ooooooooooo Il-_---_-------l-I 426 t_t
Measure voltage between 85 {+ )terminal and A26 (-) terminal.
R€pair opoi in BLU/REDwiro b€trYaen ECM lBSland A/C awilch.ls voltage less than 1.O V?
Substituto a known-good ECMand rochock, lf 3ymptom/indica-tion goos 6way, r€placo th6 orig-inal ECM.
11-85

ldle Control System
Alternator (ALTI FR Signal
This signals the ECM when the Alternator (ALT) as charging.
D9 l+)
Inspection ot ALT FR Sign.l.
Connect the tost harness betweenthe ECM and connectors. Discon-nect "D" connector from themain wire harnoss only, not theECM lsee page 11-37).
Turn the ignition switch ON.
Measure voltage between D9 (+ )terminal and A26 {-}terminal.
Sub{inno s known-good ECMand redrack. It pro.ctibod volt gola now availablg, ropllco tha orlg-inal ECM.
ls there approx. 5 V?
Turn the ignition switch OFF.
Reconnect "D" connector to themain wire harness,
Start tho engino. Hold the engine
!L3,099 rpm with no load (A/T in
LN] or El position, M/T in neutral)until the radiator tan comes on,rhen let it idle.
Measuro voltage between Dg (fl
terminal and 426 (- I terminal.
Does the voltage decreasewhen headlights and .eardelogger are turned on?Turn ths ignition switch OFF.
ALT FR rignal is OK.
o oo oo o ooooo
ooooooooooo
Voh.go?
ooooooooooo
ooooooooooo
1 1-86
(To page 1 1-87)
=-

(From page 1 1-86)
Disconnect tho nsgstive bafterycable from the baftery.
Check for continuity betwe€n D9terminal and body ground.
Check for continuity betwoan D9te.minal and body ground.
soe AIT Inrpactlon(... r.ctlon 231.Check lor continuity between D9t€rminsl snd body ground.
Rop.lt C|on in WHT/RED wi.. b.-tw.on ECM lDgl rnd ALT.
Sao ALT inapactionlres .lctlon 231.
Disconnect "D" connector lromECM only, not the main wireharnesa,
Ropair op€o in WHT/RED wito b6-tween ECM {D9} .nd .ltomrtor.
Continuity?
11-87