1999 HONDA CIVIC Intake air temp

Diagnostic Trouble Code (DTCI Chart
connector is connecteda1: Dl6Y5 engine (CVT)*2: Except D16Y5 engine (M/T)*14:'97 model*15:'96 model*16: '98 model
(cont'd)
11-97
DTC
{MlL indication*lDelection liemProbable CausePage
Manifold Absolute
Pressure Circuit
Range/Performance Problem
. Vacuu m connection. MAP sensor11115
P0107 (3)
Manifold Absolute
Pressure Circuit
Low Input
Open or short in MAP sensor circuit
MAP sensor
ECMiPCM
TCM*1
11't1'l
P0108 (3)Manifold Absolute
Pressure Circuit
High Input
Open in MAP sensor circuit
MAP sensor
ECtvt/PCM
't 1 121
P0.111*14. *15 (10)
lntake Air Temperature
Circuit
Range/Performance Problem
. IAT sensor11-124
PO112 {10}
Intake Air
Temperature Circuit
Low Input
Short in IAT sensor circuit
IAT sensor
ECMiPCM
11-125
P0113 (10)lntake Air
Temperature Circuit
High Input
Open in IAT sensor circuit
IAT sensor
ECM/PCM
't1-126
P0116 (86)Engine Coolant
Temperature Circuit
Range/Performance Problem
. ECT sensor. Cooling system11-124
PO't't7 {6)
Engine Coolant
Temperature Circuit
Low Input
Short in ECT sensor circuit
ECT sensor
ECM/PCM
11-129
P0118 (6)Engine Coolant
Temperature Circuit
High lnput
Open in ECT sensor circuit
ECT sensor
ECM/PCM
11-130
?0122 t1l
Throttle Position
CircuitLow Input
Open or short in TP sensor circuit
TP sensorECM/PCM
TCM*1
11-132
P0123 (7)Throttle Position
Circuit
High Input
Open in TP sensor circuit
TP sensor
ECM/PClvl
11-136
P0131*' (1)
Primary Heated Oxygen Sensor
Circuit Low Voltage(Sensor 1)
Short in Primary HO2S (Sensorl ) circuit
Primary HO2S {Sensor 1)
Fuel supply system
ECM/PCM
1 1-139
P0132*' ('r)
Primary Heated Oxygen Sensor
Circuit High Voltage(Sensor 1)
Open in Primary HO2S {Sensor 1} circuit
Primary HO2S (Sensor 1)
ECM/PCM
1 1- 143
P0133*' (61)
Primary Heated Oxygen Sensor
Slow Response(Sensor 1)
. Primary HO2S (Sensorl). Exhaust system11-145
P0135*? (41)
Primary Heated Oxygen
Sensor Heater
Circuit Malfunction(Sensor 1)
. Open or short in Primary HO2S(Sensor 1) heater circuit. ECM11-151
*: The DTCS in parenthesis will be indicated by the blinking of the Malfunction Indicator Lamp (MlL) when the SCS service
! ta

3.
5.
6.
1.
Fuel Cut-off Control
. During deceleration with the throttle valve closed, current to the fuel injectors is cut off to improve fuel economy at
speeds over the following rpm:. D16Y5 engine (M/T):850 rpm. D]6Y5 engine (CVT), D'16Y8 engine (USA M/T): 920 rpm
. Dl6Y8 engine (USA A,/I), D16Y7 engine (USA A,/T);910 rpm
. D16Y8 engine (Canada M/T), D16Y7 engine (canada): 990 rpm
' D16Y8 engine (Canada M/T): 1,000 rpm
. 816A2 engine: 970 rpm
. Fuel cut-off action also takes place when engine speed exceeds 6,900 rpm (D16Y5, D16Y7 engine; D'16Y8 engine:
7,000 rpm. 816A2 engine: 8.100 rpm), regardless of the position of the throttle valve, to protect the engine from
over-rewing. With '99 Dl6Y7 engine (A,/T) and '99 D16Y8 engine (A./T), the PCM cuts the fuel at engine speeds over
5,000 rpm when the vehicle is not moving.
IVC Compressor Clutch Relay
When the ECM/PCM receives a demand for cooling from the air conditioning system, it delays the compressor from
being energized, and enriches the mixture to assure smooth transition to the A,/C mode
Evaporative Emission (EVAP) Purge Control Solenoid Valve*'
When the engine coolant temperature is above 154'F (68'C). the ECM/PCM controls the EVAP purge control solenoid
valve which controls vacuum to the EVAP purge control canister.
Evaporative Emission (EVAP) Purge Control Solenoid Valve*a
When the engine coolant temperature above 154"F (68"C), intake air temperature above 32"F (0'C) and vehicle speed
above 0 mile (0 km/h) or [Ay'C compressor clutch on and intake air temperature above 160"F (41'C)], the ECM/PCM
controls the EVAP purge control solenoid valve which controls vacuum to the EVAP purge control canister.
Exhaust Gas Recirculation (EGR) Control Solenoid Valve*?
When EGR is required for control of oxides of nitrogen (NOx) emissions. the ECM controls the EGR control solenoid
valve which supplies regulated vacuum to the EGR valve
Alternator Control
The system controls the voltage generated at the alternator in accordance with the electrical load and driving mode,
which reduces the engine load to improve the fuel economy.
ECM/PCM Fail-safe/Back-up Functions
1. Fail safe Function
When an abnormality occurs in a signal from a sensor, the ECM/PCM ignores that signal and assumes a pre-pro-
grammed value for that sensor that allows the engine to continue to run.
2. Back-uD Function
When an abnormality occurs in the ECM/PCM itself, the fuel injectors are controlled by a back-up circuit independent
of the system in order to permit minimal driving.
3. Self diagnosis Function lMalfunction Indicator Lamp (MlL)l
When an abnormality occurs in a signal from a sensor, the ECM/PCM supplies ground for the lvllL and stores the DTC
in erasable memory. When the ignition is initially turned on, the ECM/PCM supplies ground for the MIL for two sec-
onds to check the MIL bulb condition.
4. Two Trip Detection Method
To prevent false indications, the Two Trip Detection Method is used for the HO2S, fuel metering-related. idle control
system, ECT sensor, EGR system and EVAP control system self-diagnostic functions. When an abnormality occurs,
the ECM/PCM stores it in its memory. When the same abnormality recurs after the ignition switch is turned OFF and
ON 0l) again, the ECM/PCM informs the driver by lighting the MlL. However, to ease troubleshooting, this function is
cancelled when you jump the service check connector. The MIL will then blink immediately when an abnormality
occurs,
5. Two (or Three) Driving Cycle Detection Method
A "Driving Cycle" consists ot starting the engine. beginning closed loop operation, and stopping the engine. lf misfir-
ing that increases emissions is detected during two consecutive driving cycles, or TWC deterioration is detected dur-
ing three consecutive driving cycles, the ECM/PCM turns the MIL on. However, to ease troubleshooting, this function
is cancelled when you jump the service check connector. The MIL will then blink immediately when an abnormality
occurs.
(cont'd)
1 1-1 05
.1.

PGM-FI System
Intake Air Temperature (lAT) Sensor ('96 - 97 Models)
The scan tool indicates Diagnostic Trouble code (DTC) P0111: A range/performance problem in the lntake AarTemperature (lAT) Sensor circuit.
The IAT sensor is a temperature dependant resistor (thermistor). The resistance of the thermistor decreases as the intakeair temperature increases as shown below.
RES|STAI{CE {tol
. 32 .. ro. tr. 2r, zaa r..l-20 o 20 /|o ao ao 100 rrotlcl
INTAIG AIR TEMPEMTURE
- The MIL hss beon reported on.- DTC P0111 is stored.- Or from Probable C.use List.
Problem verification:1. Turn the ignition switch OFF.2. Disconnect the IAT sensor 2Pconnector,3. Remove the IAT sensor.4. Reconnect the IAT sensor 2p
5. Leave the IAT sensor exposedto ambaent temperature,6. Turn the ignition switch oN fll).7. Check the IAT with the scantool.
Rsplscg the IAT sensor.
Check tho IAT sensor output:1. Warm the IAT sensor with ahair dryer-2. Check the IAT with the scantool.
Did the IAT rise 2"F (1.C) or morefrom the ambient temperature?Int€rmittont failu.e, system is OKat this time.
Replsce the IAT sensor.
11-124

IIntake Air Temperature (lATl Sensor
The scan tool indicates Diagnostic Trouble Code {DTC) P0112: A low voltage (high temperature) problem in the
lntake Air Temperature (lAT) sensor circuit.
RESISTANCE IKOI
.-l
*2: lf the engine is warm, it will be
higher than ambient temPerature.
IAT SENSOR 2P CONNECTOR {C112)
. a2 .. toa rra rrl l:rt t.al20 0 20 ro ao ao too t2ot.cl
INTAXIE AIR TEMPEFATURE
IAT{RED/YEL)
termrnars
-+-r
I'l'l-_T-
I=
Wire side of female
The MIL has been Teported on.
DTC P0112 is stored.
Problem verification:1. Turnthe ignition switch ON 1ll)2. Check the IAT with the scan
tool-
ls 302'F (150"C) or hagher (or
H Limit in Honda mode ot
PGM Tester) or 0 V indicated?
ls the correct ambrent temper
ature indicatedi'?Roolac€ tho IAT 3ensor.
lntermittent failure, svstom is OK
6t this tim€. Check for Poor Gon-
nections or loos€ wires st C112
{lAT.en3orl and ECM/PCM.
Check tor a shon in the IAT sen-
sor:1. Disconnect the IAT sensor con
nector.2. Check the IAT with the scan
tool.
ls 302"F (150'C)or higher (or
H'Limit in Honda mode of
PGM Tester) or 0 V indicated?
Ch6ck for s short in the wira (lAT
lin€):1. Turn the ignition switch OFF
2. Disconnect the ECM/PCM con-
nector D (16P) (C (31P))*'.
3. Check for continuity between
the IAT sensor 2P connector ler-
minal No. 2 and body ground.
Reoair short in the wire bstweenECM/PCM tD8 (c25)'1) and IAT
Substitute a known-good ECM/
PCM and recheck. It normel IAT
is indicated, replace the original
ECM/PCM.
* l: '99 - 0O models except Dl6Y5 engine with M/T-rf,
11-125

PGM-FI System
Intake Air Temperature (lAT) Sensor
('96 - 98 Models,'99 - 00 D16Y5 engine with M/Tl
11-126
The scan tool indicates Diagnostic Trouble Code (DTC) POl13: A high voltage flow temperature) problem in theIntake Air Temperature (lAT) sensor circuit,
taT sENsoR 2P CONNECTOn (Cl12l
I' jrl
SG2 '---.]__+ tAT(GRN/BLKI I I IRED/YEL}
JUMPERWIRE
Wire side of female terminals
ECM/PCM CONNECTOR D (16PI
IAT IRED/YEL)sG2(GRN/BLK)
JUMPER WIRE
Wire side of female terminals
The MIL has been reported on.DTC P0113 b sto.6d.
Problem veritication:1. Turn the ignition switch ON (ll).2. Check the IAT with the scantool.
Intermittent tailuJe, systom is OKat this time, Check to. poor con-nections or loose wir.s at C112{lAT senso.l .nd ECM/PCM,
ls -4'F 1-20"C) or less (or L Limitin Honda mode of PGNI Tester) or5 V indicated?
Check for an open in the IAT sen-sol:1. Disconnect the IAT sensor 2pconnector,2. Connect the IAT sensor 2P con-nector terminals No, 1 andNo.2 with a jumper wjre.3. Check the intake air tempera,ture with the scan tool.
ls -4"F ( 20'C) or less (or L-Limitin Honda mode of PGM Tester) or5 V indicated?Repbce the IAT sensor.
Check tor an open in th6 wires{lAT. SGzline!):1. Turn the ignition switch OFF.2. Connect ECM/PCM connectorterminals D8 and D11 with a
3. Turn the ignition switch ON (ll).4. Check the IAT with the scantool.
ls -4"F ( 20'C) or less (or L-Limitio Honda mode ol PGM Tester) or5 V indicated?
R€p6ir opan in the wiro! hweenEC-M/PCM lD8. 011l and IAT sen-
Substitute a known-good ECM/PCM end recheck. lf normal IATis indic.ted, replace the originalECM/PCM.

L
I
Intake Air Temperature (lAT) Sensor
('99 - 00 Modeis except D16Y5 engine with M/Tl
The scan tool indicates Diagnostic Trouble code (DTC) P0113: A high voltage (low temperature) problem in the
Intake Air Temperature (lAT) sensor circuit.
IAT SENSOR 2P CONNECTOB IC112'
r-+-r
It l,lsG2 L1__f lAr
IGRN/BLK} I I (RED/YELI
JUMPERWIRE
Wire side of female terminals
Wire side of lemale terminals
The MIL has be€n rePorted on.
DTC P0113 i3 stored.
Probl€m vetification:1. Turn the ignition switch ON (ll).
2. Check the IAT with the scan
tool.
Intormittont f.iluro, tyrtom i. OK
.t thi! tim.. Chocl for Poor con'
nactions or looso wit6 !t C112
tlAT ..n!or) rnd ECM/PCftl,
ls -4"F (-20"C) or less (or L-Limit
in Honda mode of PGM Tester) or
5 V indicated?
Check tor an open in tho IAT son'
304:1. Disconnect the IAT sensor 2P
connector,2. Connect the IAT sensor 2P con_
nector terminals No. 1 and
No.2 with a jumPerwire.
3. Check the intake air tempera-
ture with the scan tool.
ls -4"F {-20"C) or less (or L-Limit
in Honda mode of PGM Tester) or
5 V indicated?
Check lor an open in iho wirg3
{lAT, SG2 linesl;1. Turn the ignition switch OFF
2. Connect ECM/PCM connector
terminals C18 and C25 with a
iumper wire.3. Turn the ignition switch ON (ll)
4. check the IAT with the scan
tool.
Roprir opan in tho wilaa brlwocn
ECM/PCM (C18, C25l .nd IAT
!on30r.
ls -4"F (-20"C) or less (or L-Limit
in Honda mode oI PGM Testerlor
5V indicated?
substituts a known'good ECM/
PCM and recheck. ll normal IAT
is indicated, replace the otiginal
ECM/PCM.
ECM/PCM CONNECTOR C (31PI
JUMPER WIRE
11-127

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)

\J
Fuol Iniection Air {FlA) Contlol Valve T$ting
1. Start the engine.
2. Remove the vacuum hose from the fitting on the
intake air duct, and connect a vacuum gauge to the
nose.
NOTE: Engine coolant temperature must be below
149"F (65"C).
VACUUM PUMP/GAUGE,
0-30 in.Hg.A973X - 041 -XXXXX
Raise and lower the engine speed, and make sure
the vacuum gauge reading changes as the engine
speed changes.
lf vacuum reading does not change check these
rtems:
. The vacuum lines of FIA system for misrouting,
leakage, breakage and clogging.
. The FIA controt valve for cracks or damage
. The cooling system (see section 10).
Hold the engine at 3,OOO rpm with no load (in Park
or neutral) until the radiator fan comes on, th€n let
it idle and recheck.
lf vacuum reading changes check these items:
a The FIA control valve for cracks or damage.
. The cooling system (see section 10).
11-251