2000 HONDA CIVIC Ignition system

ldle Gontrol System
The (Rotary) IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the
ECM/PCM in order to maintain the proper idle speed.BIMETALHOLDER
BIMETAL
SHAFTVALVESTOPPER
ECM/PCM CONNECTOR B {25P}
(To page 11-201)
IAC VALVE 3P CONNECTOR
IACV NIACV P
ldle Air Control {lACl Valve ('99 - 00 A/T and Dl6Y7 enginel
YES
1P1509 lThescantool indicates Diagnostic Trouble Code (DTC) P1509:A problem inthe idleAirControl (lAC)valve circuit.
IGP
Terminal side of maleterminals
Sub3titute e known-good ECM/PCM .nd recheck. lf 3vmptom/indicalion goos away, replac6thc original ECM/PCM.
*: IACV N line
11-200
Tho MIL has b€en reported on.OTC P1509 is sto.ed.
Problem verilicationr1. Do the ECM/PCM Reset Proce-dure.2. Turn the ignition switch ON (ll).
Intermittont tailure, sy3tem i3 OKat thb time. Check for poor con'noctions or loose wiros at C109(lAC velvel and ECM/PCM.
ls DTC P1509 indicated?
Check for an oDen in the wilosIPG linesl:Measure voltage between bodyground and ECM/PCM connectorterminals 82 and 810 individually.
Ropail open in the wires be'tw€enECM/PCM .nd G101 llocated .tthe the.mostat housingl.ls there more than 1.0 V?
Check tho ECM/PCM input volt-age:1. Turn the ignition switch OFF.2. Disconnect ECM/PCM connec-tor A (32P)trom the ECM/PCM.3. Turn the ignition switch ON (ll).
4, Measure voltage betweenbody ground and ECM/PCMconnector terminals 86 and815* individually.
Chock the IAC v.lve:1. Turn the ignition sw;tch OFF.2. Disconnect the IAC valve 3Pconnoctor.3. Measure resistance betweenIAC valve 3P connector termi'nal No. 2 and terminals No. 1and 3 individually.
ls there 16 - 28 O?
Wire side of female terminals

ldle Control System
Starter Switch Signal ('96 - 98 Models,'99 - 00 D16Y5 engine with M/Tl
Thjs signals the ECM/PCM when the engine is cranking.
NOTE:. A/T: Transmission in E or E position. M/T: in neutral
a l32PlLGl
Wire side ot female lerminals
Check tor an open or short in thewire ISTS linel:Measure voltage between ECM/PCM connector terminals A9 andC6 with the ignition switch in thestart lllli position.
Inspect the No. 31 STARTER SIG-NAL (7.5 A) fuse in the underdashfuse/relay box.
- Repair .hort in the wirebotwoen tha ECM {C6l andtho No, 31 STARTER SIGNAL{7.5 Al tuss or the PGM-FImain relay,- Roolac. the No. 3'l STARTERSIGNAL l?.5 Al tu3€.
Staner 3witch signal is OK.
Repair opon in th6 wiro botweanih. ECII4/PCM (C6) and the No.31STARTER SIGNAL {7.5 Al tulo.
ECM/PCM CONNECTORS
{BRN/BLKISTS IBLU/ORNI
216910It3567a9l0
l2l3la15!6171a1920222att12t3l4t5t6171E
252l2A7t30232a2930
11-202

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

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)

ldle Control System
Alternator (ALTI FR Signal {'96 - 98 Models,'99 - 00 Dl6y5 engine with M/Tl
ECM/PCM CONNECTORS
a {32P)
LGl(BRN/BLK)
Wire side of female terminals
ALT CONNECTORS IC1O4I
JUMPER
JUMPER WIRE
WIRE
Wire side of female terminals
ALT F{WHT/REO)
This signals the ECM/PCM when the Alternator (ALT) is charging.
Inspoction of ALT FR Signal.
Check tor a short in tfte wire (ALTF linel:1. oisconnect the 4P (3P)* con-nector from the ALT.2. Turn the ignition switch ON (ll).3. M easu re voltage betweenECM/PCM connector terminals C17 and A9.Check lor a sho.t in the wire {ALTF line):r. I urn rne tgn|lton swtlch ul-f,2. Disconnect the negative bat-tery cable from the baftery.3. Disconnect the ECM/PCM connector C {31P).4. Check for continuity betweenbody ground and ECM/PCMconnector terminal C17.
ls there approx. 5 V?
Check th€ operation of the ALT:1. Turn the ignition switch OFF.2. Reconnect the ALT 4P (3P)*connector to the ALT.3. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untjlthe radiator fan comes on, thenlet it idle.4. [,4easu re voltage betweenECM/PCM connector terminalsC17 and A9.
Repair short in the wire betwe€nthe ECM/PCM {Cl71and th€ ALT.
Substitute a known-good ECM/PCM and recheck. It prescribedvoltage is now available, roplacethe originrl ECM/PCM.
Does the voltage decrease whenheadlights and rear defogger areturned on?ALT FR signal is OK.
Check tor an open in the wire (AlTF linel:1. Turn the ignition switch OFF.2. Disconnect the negative bat-tery cable from the battery.3. Disco n nect the ECM/PCMconnector C (31P).4. Disconnect the 4P (3P)* con,nector from the ALT.5. Connect the ALT 4P 13P)l connector terminal No. 4 (No. 1)'to body ground with a iumper
6. Check lor continuity betweenbody ground and ECM/PCMconnector terminal C17,
Repair op6n wire botween th€ECM/PCM (C171rnd th€ ALT.ls there continuity?
c {31P)
1178I10
1112131415161718
232125a30
oALT F IWHT/REDI
4P3P*
1 2l
Flr
rr-ri-frwHr/ (V)
neor Y
*: Canada model
11-208
3I78910
1l1213l415161718/l
232125E30
oALT F IWHT/REDI

ldle Control System
lgy"t9!"_"ring Pressure (PSPI Switch Signal
('96 - 98 Models, '99 - 00 DlGy5 engine witn fU/f) (USAI
This signals the ECM/ PCN4 when the power steering load is high.
ECM/PCM CONNECTORS
PSP SWITCH 2P CONNECTOR
PSP SW IGRNI
JUMPER l--L I IwfRE -2/
GND (BLKI
Wire side ol female terminais
Inspection o{ PSP switch signal.
Check for an opon in the wire {PSPSW linelr1. Turn the ignition switch ON (ll).2. Measure voltage betweenECM/PCM connecror termi-nals A9 and C16.
Check lor an open in the wire (PSPSW line):1. Turn the ignition switch OFF.2. Disconnecl the PSP switch 2p
3. Turn the ignition switch ON (ll).4. At the harness side, connectthe PSP switch 2P connectorterminals No. l and No.2with a jumper wire.5. Measure voltage betweenECM/PCM connector terminalsAg and C16.
ls there lessthan 1.0 V?
- Repair open in the wirobetween the ECM/PCM lc16land the PSP switch.- Repair open in BLK wirebetwoen the PSP switch andG101.
ls there less than 1.0 V?Check the operation of the PSPswitch:'1. Start the engine2. Turn steering wheel to full
3- Measu re voltage betweenECM/PCM connector terminalsA9 and C16.
ls there battery voltage?
PSP switch signel is OK.
Wire side oI temale terminals
11-212
(To page 11'2'13)

ldle Control System
Power Steering Pressure (PSP) Switch Signal
('99 - 00 Models except Dl6y5 engine with M/T) (USAI
This signals the ECM/PCM when the power steering load is high.
Wire side of female terminals
PSP SWTTCH 2P CONNECTOR (qts6)
PSP SW (GRN)
JUMPER T---7 1 \wlRE LJ- 2-l
GND IBLK)
Wi16 sid6 of temale terminals
ECM/PCM CONNEgTORS
Inspoction ot PSP switch signal.
Check for an op€n in the wire (PSPSW linel:1. Turn the ignition switch ON (ll).2. Measure voltage between ECN4/PCM connector terminals 426and 820.
Check for .n open in tho wire IPSPSW line):1. Turn the ignition switch OFF.2. Disconnoct the PSP switch 2Pconnector.3. Turn the ignition switch ON (ll).4. At the wire side, connect thePSP switch 2P connector ter-minals No. 1 and No.2 with ajumper wire.5. Measure voltage between ECM/PCNI connoctor terminals 426and 820.
ls there lessthan 1.0 V?
- Ropai. opgn in ths wire be-tw.€n the ECM/PCM {A261rnd th6 PSP switch.- Ropsir opon in BLK wi.o bo-twoen tho PSP switch andG101.
ls there less than 1.0 V?Check the operation ot the PSPsw;tch:'1. Start the engine2. Turn steering wheelslowly.3. Measure voltage between ECM/PCM connector terminals 426and 820.
ls there battery voltage?
PSP switch sign8l i3 OX.
11-214
(To page 11-215)

ldle Control System
Automatic Transaxle (CVTI Gear Position Signal
('96 -98 D16Y5 engine with CW)
ATP NP{LT GRNI
INP
GBN)
This signals the ECM when the transmission is in @ or @ position.
Check the operation oI the A/Tgear position switch:1. Turn the ignition switch ON flt).2. Observe the A/T shift positionindicator and select each position separately.
See lhe A/T gear position indica-tor insp€ction {see sec{ion l/tl.
Check tor a short in the wir6 (ATpNP line):1. Turn the ignition switch OFF.2. Disconnect the 14P connectorIrom the gauge assembly.3. Disconnect the 26P connectorfrom the TCM.4. Turn the ignition switch ON fll).5. Measure voltage between ECMconnector terminals A9 andc29.
Check for a short in the wire lATpNP linell1. Turn the ignition switch OFF.2. Disconnect the ECM connector C (31P).
3. Check for continuity betweenbody ground and ECM connector terminal C29.
ls there approx. 5 V?
Check for an open in the wire lATpNP lina):1. Turn the ignition switch OFF_2. Beconnect the 14P connectorto the gauge assembly.3. Reconnect the 26P connectorto the TCM.4. Sta rt the engine.5. Measure voltage betweenECM connector terminals A9and C29 with the transmission in E and E posationt
Repair short in the wire betweenthe ECM {C291 and the gaugeassemblv,
Substitute a known-good ECMand recheck. lf prescribed volt-age is now avrilable, replace theo.iginalECM.
Wire side ot female terminals
2457I910
t112131a15151718
2321252930
ATP(LT io
(To page 11'217)
11-216