1998 HONDA INTEGRA check engine

ldle Control System
ldle Control System
i P0505 | fne scan tool indicates Diagnostic Trouble Code (DTC) P0505: ldle control system malfunction,
NOTE: ll DTC Pl508 is stored at the same time as DTC P0505, troubleshoor DTC P1508 first. then troubleshoot DTC P0505.
Possible Cause
. IAC valve mechanical malfunctiorr
. Fast idle thermo valve malfunction (A"/T)
. Throttle body clogged port, improper adjustment
. Intake manifold, gasket leakage
. Intake air hose loose, leakage
a Vacuum hoses leakage
. ECT sensor incorrect output
. Throttle Position sensor incorrect output
Troubleshooting Flowchart
Problem verification:1. Start the engine. Hold theengine at 3,000 rpm wath noload 1in Park or neutral) untilthe radiator fan comes on,then let it idle.2. With the scan tool, check thefollowing items.- Throttle position should beapprox. 10% with the throttle fully closed.Engine coolant tempera-ture should be 116 212F(80 - 100'c).lf they are not within thespec., repair the faulty sensor crrcuft,3 Check the engine speed atidle with no-load conditions:headlights, blower fan, reardefogger, radiator fan, and airconditioner are not operating,
- The MIL has been reported on.- DTC P0505 is stored.
ls it 750 t 50 rpm (81881,
818C1 engines), 800 I 50 rpm(818C5 engine)?
Intermittent failur6, svstsm is OKat this tim€.
ls it 550 rpm (81881,818C1
engines), 600 rpm {818C5enginelor less?
-98
(To page 11'99)(To page 11-99)

ldle Control System
Problem verification:'1. Do the ECM Feset Procedure.2. Sta rt the engine.
ldle Air Control (lAG) Valve
The scan tool indicates Diagnostic Trouble Code (DTC) P1508: A problem in the ldle Air Control (lAC) valve
crrcurt.
The IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the Eclvl in
order to maintain the proper idle speed.FTom AIB To INTAKECLEANER MANIFOLD
IAC VALVE CONNECTOR IC116}
YES
WIRE SIDE OF FEMALE TERMINALS
ECM CONNECTOR A {32PI
Check for an open or short in thewire IIACV line):1. Turn the agnition switch OFFand reconnect the IAC valve
2. Disconnect the ECM connector A (32P).
3. Turn the ignition swatch ON (ll).
4. M easu re voltage betweenbody ground and ECM connector terminal A12.
IACV {8LK/BLU}
tacv{BLK/BI-UI
The MIL has been reoorted on.OTC Pl508 is stored.
lntermittent failure, svstem is OKat this time. Check for ooor con-nections or loose wires at C116{lAC valvel and ECM.
ls DTC P1508 indicated?
Check tor an open in lhe wirellGPl line):1. Turn the ignition switch OFF.2. Disconnect the IAC valve con
3. Turn the ignition switch ON (ll).
4. Measure voltage betlveen bodyground and the IACV connectorterminalNo.2.
Repair open in the wire betweenIAC valve and PGM-FI main relav-ls there battery voltage?
Repair open or shon in the wi.ebetween ECM {A12l and lAc valve.ls there battery voltage?
Check the IAC velve function:Momentarily connect ECM con-nector terminals A12 and A10with a jumper wire several times.
Does the IAC valve click?
Substitute a known-good ECMand rocheck. lf symptom/indica-tion goes away. replace the origi-nal ECM.
','*',,'Llu.9', I l112 15 16 17 1a1o20/
l--12u1 z"-if1za-2"' . '1 .
910
t-r '21
Wire side of female terminals
JUMPER WIRE
1-100

This signals the ECM when the Alternator (ALT) is charging.
Alternator (ALT) FR Signal
Check lor a short in th€ wire {ALTF line):1. Oisconnect the ALT GRN 4P(3P)* connector from the ALT.2. Turn the ignition switch ON {ll).3. Measure voltage between ECMconnector terminals C17 and A9.
ECM CONNECTORSA t32Pt
LG1
c 13lPl
ALT F(WHT/FEDI
Wire side of female terminals
ALT GRN 4P CONN€CTOR {C119}
JUMPER WIRE
Wire side of female terminals
ALT GRN 3P CONNECTOB {C119)*
JUMP€RWIRE
Wire side ot female terminals
12 15 t6 rr t8 19I
?
oALT F(WHT/REOI
23aI10
t112t3t5l6r819 ,/21
./,/,/2a29
[,ALT FIWHT/RED)
12339
11 12l517 tla19 ,/21
Inspection of ALT FR Signal.
Check for a shon in the wire {ALTF line):1. Turn the ignition switch OFF.2. Disconnecl the negative baatery cable from the battery.3. Disconnect the ECM connectorc (31P).
4. Check for continuity betweenbody ground and ECM con-nector terminal C17.
ls there approx.5 V?
Check the operation ofthe ALT:1. Turn the;Onition switch OFF-2. Reconnect the ALT GRN 4P(3P)* connector to the ALT.3. Start the engine. Hold theengine at 3,000 rpm wkh noload {in Park or neutral) untilthe radiator fan comes on,then let it idle.4. Measure voltage bet/veen ECMcon nector termina ls C17 and A9.
Ropair short in the wir6 betweenth6 ECM (C17) and the ALT.
Substitute a known-good ECMand recheck. It prescribed voltagGis now available, replace th€ origi-nal ECM.
Does the voltage decrease whenheadlights and rear defogger areturned on?ALT FR signal is OK.
Check tor an open in the wire {ALTF line):1. Turn the ignition switch OFF-2. Disconnect the negative bat-tery cable from the battery.3. Disconnect the ECM connector C (31P).
4. Disconnect the ALT GRN 4P(3Pi* connector from the ALT.5. Connect the ALT GRN 4P (3p)*
connector terminal No. 4 (No.'l)* to body ground with a
6. Check for continuity betweenbody ground and ECM connector terminal C17.
Ropair open wire bstw€an theECM {C17} and rhe ALT.ls there continuity?
ri Canada
11-101

Starter Switch Signal
This signals the ECM when the engine is cranking.
NOTEI. M/T:Clutch pedal must be depressed.. A,/T: Transmission in E or E position.
Wire sida of female terminals
Check for an opon or short in thcwi.. ISTS lin.l:Measure voltage between ECMconnector terminals C6 and Agwith the ignition switch in thostart position (lll).
Inspect the No.31 STARTER SIG-NAL (7.5 Alluse in the under-dashfuse/relay box,
ls there battery voltage?
- Repair 3hort in the wire be-tween tho ECM lc6l rnd theNo. 31 STARTER SIGNAL (7.sAl tus€ or the PGM-FI mainr€lay.- Roplace the No. 31 STARTERSIGNAL 17.5 Al fuso.
Starter switch signal b OK.
Ropair open in tho wire botwaonih6 ECM {CGl and the No, 3lSTARTER SIGNAL {7.5 Al fuse.
11-105

{From page 11-'106)
Check tor an op€n in the wiro {ATpPN lin€):Turn the ignition switch OFF.Fgconnect the 10P connectorto the gauge assembly.Reconnect the 26P connectorto the TCM.stan the engine.M€asure voltage between ECMconnector termanals C29 andAg with the transmission inE position.
- Ropair open in th6 wiro bo-twoen tho ECM {C291 and thogru96 a3sgmbly.- Repair open in GRN wir. bo-twaan thc gauga !srembly.nd tho A/T g.ar po3itiongwitch.
ls there less than 1.0 V?
Chod( for an opon in tho wir6 (ATPPN linel:Measure voltage between ECMconnector terminals C29 and A9with the transmission in E] posi,tron.
R.psir op.n in GRN/WHT wirob€twcan th. gaugc rsr.mbly andthc A/T ge.r po.ition 3whch.
ls there less than 1.0 V?
A/T g6er position signal i3 OK.
a l32P)LGl{BRN/BLKI
Wire side of female terminals
ATP PN{I-T GRN/BLKI
11-107

Power Steering Pressure (PSP) Switch Signal (USA)
This signals the ECM when the power steering load is high.
ECM CONNECTORS
Check lor an open in the wire (PSP
SW line):1. Turn the ignition switch ON (ll).
2. Measure voltage between ECM
connector terminals C16 andA9.
A {32P1LGl{BRN/BLK)
c (31P}
PSP SWIGRNI
Wire side oI female termanals
PSP SwlTCH 2P CONNECTOR IC311I
PSP SW {GRNI
luupen r-{ r \wrRE 4rl
GND (BLK)
Wire side oI female terminalsi,
Inspection ot PSP switch signal.
Check lor an op€n in the wire (PSP
SW linel:1. Turn the ignition switch OFF
2. Disconnect the PSP swirch 2P
3. Turn the ignition switch ON (ll).
4. At the wire side, connect the
PSP switch 2P connector ter
minals No. 1 and No.2 with a
iumper wire.5. Measure voltage teNveen ECM
connector terminals C16 andA9.
ls there less than 1.0 V?
- Repair open in the wire be-
tween the ECM lcl6l .nd the
PSP 3witch.- Repai. open in BLK wire be'
tween the PSP switch and
G301.
ls there less than 1.0 V7Check the operation of the PSPswitch:1- Stan the engine2. Turn steering wheel to full
3. Measure voltage between ECM
connector terminals c16 andA9.
ls there battery voltage?
PSP switch signal is oK.{To page l1 t09)

ldle Control System
Fast ldle Thermo Valve (A/T model onlylFast ldle I nermo valve (A/ | mooel
Description
To prevent erratic running when the engine is warming
up. it is necessary to raise the idle speed. The fast idle
thermo valve is controlled by a thermowax plunger.
When the engine is cold, the engine coolant surround-
ing the thermowax contracts the plunger, allowing addi
tional air to be bvoassed into the intake manifold so that
the engine idles taster. When the engine reaches operat-
ing temperature, the valve closes. reducing the amount
of air bypassing into the manifold.
FAST IDLE THERMO
VALVE
VALVE
wAx
Inspection
NOTE: The fast idle thermo valve is factory adiusted; it
should not be disassembled.
1. Remove the intake air duct from the throttle body.
2. Start the engine.
3. Put your finger over the lower port in throttle body
and make sure that there is air flow with the engine
cold {engine coolant temperature below 86'F, 30"c).
LOWERPORT
lf there is no air flow, replace the last idle thermo
valve and retest.
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.
Check that valve is completely closed. lf not, air suc-
tion can be felt at the lower port in the throttle body.
l{ any suction is felt, the valve is leaking. Check
engine coolant level and for air in the engine
coolant system (see section 10). It OK, replace the
fast idle thermo valve and recheck.
5.
{1.0 kg.m,7.2lbftl
l
11-110
lL.

ldle Speed Setting
IDLEADJUSTINGSCREW
7.
6.Turn the ignition switch OFF.
Reconnect the 2P connectors to the IAC valve and
the EVAP purge control solenoid valve, then do the
ECM reset procedures.
Restart and idle the engine with no-load conditions
for one minute, then check the idle speed.
NOTE: (Canada) Pullthe parking brake lever up.
Start the engine, then check that the headlights are off.
ldle speed should be;
Bl88l €ngine:
Mfi750 i 50 rpm
A/T750150 rpm (in Park or neutral)
818C1 engine:750 i 50 rpm
818C5 engine: 800 i 50 rpm
NOTE: 81881, Bl8Cl engines - It the idle speed
increases to *1rpm, this means the EVAP system ispurging the canister. To stop the purging termporarily.
raise the engine speed above 1,000 rpm with the
accelerator pedal, then slowly release the pedal.
*1: 81881 engine
M/T: 820 i 50 rpm
Ay'T: 840 t 50 rpm
818Cl engine
850 I 50 rpm
(cont'd)
Inspection/Adiustmont
NOTE:
. When setting the idle speed, checkthe following items:- The MIL has not been reported on.- lgnition timing
Spark plugs- Air cleaner- PCV system
. (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 with
no load (in Park or neutral) until the radiator fan
comes on, then let it idle,
Connect a tachometer.
Disconnect the 2P connectors from the ldle Air
Control (lAC) valve and the EVAP purge control
solenoid valve.
2.
5.
if the engine stalls, restan the engine with the accel
erator pedal slightly depressed. Stabilize the rpm at
1,000, then slowly release the pedal until the engine
idles.
Check idling in no-load conditions: headlights, blower
fan, rear defogger, radiator fan, and air conditioner
are not ope€tlng.
ldlo speed should be;
B188l engine:
Mlf480 :l 50 rpm
A/T480 i 50 rpm (in Park or neutral)
B18C1 engine: /t80 t 50 rpm
818C5 sngine:550 t 50 rpm
lf necessary, adjust the idle speed, by turning theidle adjusting screw.
After adjusting the idle speed, recheck the ignition
timing {see section 23). lf it is out of spec, go back
to steo 4.