1999 HONDA CIVIC engine fan

Knock sensor (Ks) r99 - 00 D16Y5 engine with cw, '99 - 00 D16Y8 engine and
816A2 engine
The scan tool indicates Diagnostic Trouble Code (DTC) P0325: A malfunction in the circuit of the Knock Sensor
{KS}.
OIAPHRAGM
ECM/PCM CONNECTOR C (31P)
KS 2P CONNECTOR (C1371
KS
Wire side of female terminals
t
The MIL has been reported on.
DTC m325 is stored
Problem verification:1. Do the ECM/PCM Reset Pro
cedure,2. 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.
3. Hold the engine at 3.000 -
4,000 rpm for at least 60 sec'
onds.
lntermittent failure, system is OK
at thi3 time lt€3t drive maY b€
nocessaryl.Chsck tor poor connections or
loose wiros at C137 {knock sen'
sor {KSll and ECM/PCM.
ls DTC P0325 indicated?
Ch€ck for a short in tho wire (KS
linel:1. Turn the ignition switch OFF.
2, Disconnect the knock sensor
1P connector.3. Check for continuity between
ECM/PCM connector termi_
nals C3 and body ground.
Repri. short in the wiro bqtwecnECM/PCM lc3l and knock 3ensor.ls there continuity?
Check for an open in lhe wire
{KS linc):Check for continuity between
ECM/PCM connector terminal C3
and knock sensor connector ter-
minal No. 1.
Replir open in the wire bdtweon
ECM/PCM {Ctl and knock sensor'
SubstitLrte a known'good knock
sensor and recheck,
Replace tho otiginal knock sensor.
substitute a known-good ECM/PCM and recheck. ll symptom/indication goes awaY, rePl6co
tha o.iginal ECM/PCM.
Wire side of female terminals
ECM/PCM CONNECTOR
11-171

PGM-FI System
Barometric Pressure (BAROI Sensor
The scan tool indicates Diagnostic Trouble code (DTC) Pi106: A range/performance problem in the BaromerrrcPressure (BARO) Sensor circuit.
The scan tool indicates Diagnostic Trouble code (DTc) P1107: A low voltage probtem in the Baro sensor circurr.
The scan tool indicates Diagnostic Troubre code {DTC) p1108: A high vortage probrem in the Baro sensorcircuit.
fF1lot
tPlloal
The MIL ha3 been r€Dortsd on.DTC Pl106 is stored.
Problem verification:1. Do the ECM/PCM reset pro-cedure,2. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator fan comes on, thenlet it idle.3. Connect the SCS service connector.4. Test drive with the A/T in Eposition, M/T in 4th gear.5. Accelerate for five secondsusing wide open throttle.
Intormittont tailure, system is OKat this time.ls DTC P1106 indicated?
Substitut€ e known-good ECM/PCM and recheck. ll symptom/indication goes .way, .oplsce theo.iginal ECM/PCM.
The MIL has been .oported on.DTC P'l107 o. Pl108 is stored.
P.oblem veritication:1. Do the ECM/PClvl Reset pro
cedure,2. Turn the ignition switch ON (ll).
Intormittent frilure, syitem i3 OKat this time.ls DTC P1 107 or Pl108 indicated?
Substitute a known-good ECM/PCM and rechock. It symptom/indication goes away, .6placethe original ECM/PCM.
11-178

ldle Control System
ldle ControlSystem
lF0505 l Th" """n tool indicates Diagnostic Trouble Code (DTC) PO5O5: tdte controt system malfunction.
NOTE: lf DTC P1508 or P1509 is stored at the same time as DTC P0505, troubleshoot DTC p1508 or p1bog first. thenrecheck for DTC P0505.
Possible Cause
. IAC valve mechanical malfunction
. Throttle body clogged pon, improper adjustment. Intake manifold gasket leakage
. Intake air hose loose leakage
. Vacu um leak
. ECT sensor incorrect output
. Throttle Position sensor incorrect output*r
Troubleshooting Flowchart
The MIL has been reoorted on.DTC P0505 is stored.
Problem verification:1. Start the engine. Hold theeng;ne at 3,000 rpm with noload (jn Park or neutral) untilthe radiator fan comes on, then*r let it idle.t2. with rhe scan toot, ct'eit Ge l
Throttle position should beapprox. 10% with the throttle fully closed.E ngine coolant tempera-ture should be 194 205'F(90 96.Ci.lf they are not within thespec., repair the faulty sen
L._ _9oI9[cr]41 l3. Chec& the engine speed atidle with no-load cond;tionsiheadlights, blower fan, reardefogger, radiator fan, and airconditioner are not operating\see page l1-22O - 223).
Intermittent tailure, system is OKat this time.ls the idle speed OK?
ls it 550 rpm or less?
(To page 11,193)
*1r'96 models only
11-192
(To page ll-193)

ldle Control System
ldle Air Control (lACl Vatve ('96 - 98 Dl6ys, Dl6yB engine with M/Tl
The scan tool indicates Diagnostic Trouble Code (DTC) P1508: A problem 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 inorder to maintain the proper idle speed.
IAC VALVE 2P CONNECTOR ICl3A)
,flrcerh-:J iYEL/BLKI
!.__-,/ -lt(v)
-T-=
Wire side of female terminals
tAcv(BLK/
ELUI
ECM CONNECTOR A I32PI
Wire side oI lemal€ terminals
VALVE
6a10ll12t3r5t6l7t8t920232a
t*25&a2A3o
The MIL hss b€on repo.ted on.DTC P'l508 i. itorod.
Problem vorification:1. Do the ECM/PCM Reset Pro-cedure,Start the engine, and warm ituP to normal operating tem-perature.
Intormittont t!llur., sy.tcm b OKat thb tim6. Chsck fol poor con-ncctionr or loo3e wirot at C138(lAC valv.l.nd ECM.
ls DTC P1508 indicated?
Check for an opcn in the wiro(lGPl line):1. Turn the ignition switch OFF.2. Disconnect the IAC valve 2Pconnector.3. Turn the ignition switch ON (ll).
4. Measure vohage between bodyground and the IAC valve 2Pconnectorterminal No. 2.
R.prir opan in the wiro botwa.nIAC valv..nd PGM-FI main r.l.y.
Chock for an opon or sho in thewire (IACV linal:1. Turn the ignition switch OFFand reconnect the IAC valveconnector.2. Disconnect the ECM connectorA (32P).
3. Turn the ignit;on switch ON (ll).4. Measure voltage betweenbody ground and ECM con-nector terminal A12.
(To page 1l-195)
11-194

ldle Gontrol System
ldle Air Control (lAG) Valve ('99 - 00 Dl6Y8 engine with M/T, Bt6A2 enginel
[Fl50g l ]h" scan tool indicates Diagnostic Trouble Code (DTC) P1508: A problem in the ldle Air Controt AC) vatve- CtrCUtt.
The IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the ECM inorder to maintain the proper idle speed.
IAC VALVE 2P CONNECTOR IC138'
la rcprI - {YEL/8LKI 2t--d,
Y-=
Wire side ot female terminals
Wire side of lemale terminals
VALVE
The MIL has boon r€oorted on.DTC P1508 is srored.
Probl6m verification:1. Do the ECM/PCM Reset Pro-cedure.2. Start the engine, and warm itup to normal operating lem-perature.
Intermittent tailure, system is OKat this timg. Check to. poor con-noctions or loose wires at C138{lAC valvel and ECM.
ls DTC P1508 indicated?
Ch6ck for an open in the wir€{lGPl lino}: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 2Pconneclor termina I No.2,
Repair opon in the wire bgtwoenIAC valve and PGM-Fl main relay.
Check tof an open or short in thewire {IACV line}l1. Turn the ignition switch OFFand reconnect the IAC valve
2. Disconnect the ECM connectorB {25P).3. Turn the ignition switch ON (ll).
4. Measure voltage betweenbody ground and ECM conn€ctor terminal 823.
(To page 11-197)
1 1-1 96

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

tAlternator (ALT) FR Signal ('99 - 00 Models except Dl6Y5 engine with M/T)
This signals the ECM/PCM when the Alternator {ALT) is chargingECM/PCM CONNECTORS
Wire side of female terminals
ECM/PCM CONNECTOR C (31P}
lt
lP
ALT CONNECTORS IClO4I
JUMPER
JUMpER WlnE
WIRE
Wire side of female termlnals
ECM/PCM CONNECTOR C (31PI
3P*NO
Check lor an op€n in the wire (ALT
F line,:1. Turn the agnition switch OFF
2. Disconnect the negative bat-
tery cable {rom the battery.
3. Disconnect the ECM/PCM con'
nector C (31P).
4. Disconnect the 4P (3P)* con'
nector from the ALT.
5. Connect the ALT 4P (3P)* con-
nector terminal No 4 (No. 1)*
to bodY ground with a iumper
6. Check lor continuity between
body ground and ECM/PCM
connector terminal C5
--?--1l2l|#i3l.l
otriJrwxrr (V)
neor Y
lnsoeclion oI ALT FB Signal.
Check {or a short in the wire {ALT
F line):1. Disconnect the 4P (3P)+ con
nector from the ALT
2. Turn the ignition switch ON (ll)
3. Measurc voltage between EcM/
PCM connector terminals C5
and 820.Check tor a short in the wirc (ALt
F line):1. Turn the ignition switch OFF
2. Disconnect the negative bat_
tery cable from the baRery'
3. Disconnect the ECM/PCM con'
nector C (31P).
4. Check for continuity between
body ground and ECM/PCM
connector terminal C5
ls there aPProx. 5 V?
Check the operation otthe ALT:
1. Turn the ignition switch OFF.
2- Reconnect the ALT 4P (3P)*
connector to the ALT
3. Start the engine. Hold the
engine at 3,000 rpm wrth no
load {in Park or neutrali until
the radiator fan comes on,
then let it idle.
4- Measure voltage between ECM/
PCM connector terminals C5
and 820.
Repair short in the wire between
the EcM/PCM {C5l and the ALT.
Substitute a known-good ECM/
PCM and rechock. lf P.esc.ibedvoltage is now availabl€, ieplace
tho original ECM/PCM
Does the voltage decrease when
headlights and rear delogger are
turned on?
ALT FF signal is OK.
Repair oPen wire betwoen t|lo
ECM,/PCM {C5) and the ALT.
ALT F (WHT/RED)
Wire side of temale terminals
*: Canada model
Wire side of female termrnals

ldle Control System
ldle Speed Setting
Inspection/Adiustmenl
'96, '97 Dl6Y5. '96 - 00 Dl5Y8 sngine with M/T
NOTE:
. Before setting the idle speed, check the following
items:- The MIL has not been reported on.- lgnition timing- Spark plugs- Air cleaner- PCV system
o (Canada) Pull the parking brake lever up. Start the
engine, then check that the headlights are off.
1. Start the engine. Hold the engine at 3.000 rpm withno load (taansmission in neutral) until the radiatorfan comes on, then let it idle.
2. Connect a tachometer.
3. Disconnect the IAC valve connector.
4.lf the engine stalls, restart the engine with the accel-
erator pedal slightly depressed. Stabilize the rpm at1,000, then slowly release the pedal until the engineidles.
Check idling in no-load conditionsr headlights. blowerfan. rear defogger, radiator fan, and air conditioner
are not operating.
ldle spsed should be:
450 1 50 rpm
11-220
Adjust the idle speed, if necessary, by removing thecap and turning the idle adjusting screw.
NOTE; After adjusting the idle speed in this step,recheck the ignition timing (see section 23).
lf it is out of spec, go back to step 4.
IDLE
6. Turn the ignition switch OFF.
7. Reconnect the 2P connector on the IAC valve, then
do the ECM reset procedure.
8. Restart and idle the engine with no-load conditionsfor one minute, then check the idle speed.
NOTE: (Canada) Pull the parking brake lever up.Start the engine, then check that the headlights areoff.
ldle sp€sd should b€:
670 i 50 rpm IUSA)750 t 50 rpm {Canada}
9. ldle the engine tor one minute with headlights {Low)ON. and check the idle speed.
ldle speed should be:
750 :r 50 rpm
10. Turn the headlights off. ldle the engine for oneminute with heater fan switch at Hl and air conditioneron, then check the idle speed.
ldle speed should be:
810150 rpm
NOTE: lf the idle speed is not within specification,see Symptom Chan on page 11-84.