1996 HONDA CIVIC heater

Heated Oxygen Sensor (HO2SI Heater (Dl6Y5 engine with M/Tl
The scan tool indicates Diagnostic Trouble Code (DTC) P1166: An electrical problem in the Primary Heated
Oxygen Sensor (Primary H02S) Heater system.
PRIMABY HO2S ISENSOR 1I 8P CONNECTOR
Terminal side ofmale terminals
I(cont'd)
11-161
- The MIL has been lePorted
- DTC Pl166 b stored.
Problem verilication:1. Do the ECM Reset Procedure.
2. Start the engine.
Intermitlent failura, sYstem b OK
at this time (te3t drive maY be
ngcessary). Check for poor con-
nections or loose wires between
C145 (Primary HO2S, Sen3or 1l
end ECM.
ls DTC P'l166 indicated?
Check the Primary HO2S (Sensot
1l resistence:1. Turn the ignition switch OFF
2. Disconnect the Primary HO2S(Sensor 1) 8P connector.
3. At the Primary HO2S (Sen
sor 1), measure resistance
between No. 1 and No. 2 ter_
Replace lhe Primery HO2S (Sen-
sor 11.ls there 2 13 O?
Check for a shorted PrimarY
HO2S lsensor 1):Check for continuity between
body ground and each terminal.
Check for a shorted PrimarY
HO2S {S€nsor 1l:
Check for continuity between ter'
minal No. 1 and terminals No.3,
4, 6, 7 and 8 individually.
ls there conlrnuily?
(To page 11'162)

PGM-FI System
I
a
a
Ch6ck the PO2SHTC circuit:1. Start engine and keep enginerpm at idle.2. At the engine wire harness,measure voltage betweenPrimary HO2S (Sensor 1) 8Pconnector terminal No. 1 terminal and body ground.
Check for an open in the wire(PG linellMeasurc voltage between PrimaryHO2S (Sensor 1) 8P connector ter-minals No. l and No.2.
ls there morethan 5 V?
Repair opon in the wi.o bEtwoonthe HO2S.nd G101 (located atth.rmonat housingl.
ls there more than 5 V?
Substitule a known-good ECM.nd .echeck. lt 3ymptom/indica-tion 906! rwry, roplace the origi-nal ECM,Check lor a short in the wire
{PO2SHTC line):1. Turn the ignition switch OFF.2. Disconnect ECM connector A(32P)trom the ECM.3. Check for continuity betweenECM connector terminal 46and body ground.
Ropair 3hort in tho wire betwoenthe ECM {46} and the Prim.ryHO2S lson3or 11.
Check for an open in the wire(PO2SHTC linel:Check for continuity betweenECM connector terminal 46 andthe Primary HO2S (Sensor 1)8Pconnector terminal No. 1.
Repair opsn in the wir6 botweenECM {A6} .nd the Primary HO2Slsonror 1).
Substituto a known-9ood ECMand rech6ck. lf symptom/indica-tion goes away, replace the origi-nal ECM.
Heated Oxygen Sensor (HO2S) Heater (Dl6Y5 engine with M/Tl (cont'd)
(From page 11-161)PRIMARY HO2S (SENSOR 1} 8P CONNECTOR {Cl45I
PO2SHTC{BtK/WHT)
PO2SHTCIALK/WHTI
ECM CONNECTOR
female terminals
11-162
\.
!
\
A {32P}
o
6I9l roIt
12t3l5t61't8t9a221 232a
252'2aEito,1| ---

The scan tool indicates Diagnostic Trouble Code (DTC) Pl167: A system malfunction in the Primary Heated
Orygen Sensor {Primary HO2S) (Sensor 1) Heater circuit
PRIMABY HO2S ISENSOR 1} 8P CONNECTOR
tc145l
ECM CONNECTOR C (31P)
- The MIL has be€n reported on.- DTC Pl167 i3 3tored.
Problem Veritication:1. Do the ECM Reset Procedure.
2. Start the engine. Hold the
engine at 3,000 mm with no
load (transmission in neutral)
until the radiator fan comes
on.Intormittont failure, system i3 OK
at thia time. Chock for Poor con_
noction3 or looso wilgt ai Cl45(Primary HO2S, Son3or 1l andECM.
ls DTC1167 indicated?
Check lor sn open in the wire(VS+ linel:1. Turn the ignition switch OFF
2. Disconnect the Primary HO2S
{Sensor 1) 8P connector.
3. Turn the ignition switch ON (ll).
4. Measure voltage betwe€n thePrimary HO2S (Sensor '1) 8P
connector terminal No 6 and
body ground.
Ch.ck the ECM:Measure voltage between the
ECM connector terminsl C25 and
body ground.
ls there more than 5 V?
Repair opon in the wite ECM (C25)
and P m.ry HO2S (S€n3or 11.ls there more than 5 V?
Replaco the Primary HO2S (Son-
sor 11.Substitute ! known-good ECM
and r6check. lf symptom/indica-tion gos6 away, r.place tho origi'
nd ECM,
,l23458910
111213t415161718
a2125a30
VS+{WHTIWire side of femaleterminals
1 1-163

PGM-FI System
Fuel Supply System
D017-il Th""""ntool indicates Diagnostic Troubte Code {DTC) p0171;Thefuet system istoo lean.
1P0172 | fne scan tool indicates Dlagnostic Trouble Code (DTC) P0172:Thefuel system istoo rich.
Description
By monitoring the Long Term Fuel Trim, long term malfunctions in the fuel system will be detected.lf a malfunction has been detected during two consecutive trips, the MIL will come on and DTC P0171 and/or P0172 will bestored.
NOTE: lf some of the DTCS listed below are stored at the same time as DTC P0171 andlot P0172, ltouhleshoot those DTCSfirst. then recheck for DTC P0l7l andlot P0172.
P0106-8, P1128*3. *5, P1129*3 *5 MAP Sensor
P0135; Primary HO2S Heater
P0137. P0138: Secondary HO2S
P0'141: Secondary HO2S Heater
P0401: EGR Flow Insufficient*1
P0441: EVAP System Insufficient Purge Flow*6
P1259: VTEC System*,
P1491:EGR Valve Lift Insufficient*r
P1498: EGR Valve Lift Sensor Hjgh Voltage*r
*r: D16Y5 engines*': Dl6Y5, D16Y8, 81642 engine*3: '97 models*a:'96 modelsf 5: '98 - 00 models*6: '96 D16Y5 engine,'96 D16Y7 engine,'96 D16Y8 engine (sedan),'97 D16y5 engine,,97 D16y7 engine (coupe: KA, KC mo+els, sedan KA. KC, KL (DX) models. hatchback; all models),'97 D16Y8 engine (sedan: KA, KC models)
Possible Cause
DTC P0'171
loo lean
DTC P0172
too rach
Fuel Pump insuff icient f lovpressure
Fuel Feed Line clogged, leaking
Fuel Pressure Regulator stuck open
Fuel Filter clogged
Fuel Injector clogged, air inclusion
Gasoline doesn't meet Owner's Manual spec.
Primary HO2S (Sensor 1) deteriorated
MAP Sensor range/performance*.
EGR System malfunction (too much flow)*1
Valve Clearance
Exhaust leak
Fuel Pressure Regulator clogged, stuck closed
Fuel Return Pipe clogged
Fuel Injector leaking
Gasoline doesn't meet Owner's Manual spec.Primary HO2S (Sensor 1) deteriorated
MAP Sensor range/performance*a
EGR System insufficient flow*1
EVAP Purge Control Solenoid Valve leaking, stuck opened
Valve Clearance
11-164

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.

t
t
I
'96.'97 D16Y5 engine with CVT,'96 - 00 D16Y8 ongins
with A/T and'96 - 00 Dl6Y7 €ngine
Adiust the idle speed using a Honda PGM Tester if pos-
sible. lf not, use the following procedure:
NOTEI
. Leave the IAC valve connected
. Betore setting the idle speed. check the following
items:- The MIL has not been reported on'
- lgnition timing
- Spark Plugs- Air cleaner- PCV system
1. Connect a tachometer.
2. Start the engine. Hold the engine at 3,000 rpm wirh
no load (in Park or neutral) until the radiator fan
comes on, then let it idle.
3. Check the idle speed with no-load conditions: head-
iights, blower fan, rear defogger, radiator fan, and
air conditioner are not operatlng
ldl€ spoed should be:
USA:
D16Y5 engine with CVT, D16Y7 engine with A/T'
Dl6YB engine with A/T:
700 :r 50 rpm (in E or El Positionl
D16Y7 engine with M/T:
670 i 50 rpm
Canada:
Dl6Y8 sngin€, Dl6Y7 engins:
M/T750 t 50 rpm
NT750 1 50 rpm (in E or El Position)
Adjust the idle speed, if necessary, by removing the
cap and turning the idle adiusting screw 1/2-turn
clockwise or counterclockwise
D16Y5, D16Y8 engine:
IDLEADJUSTING
Dl6f, ongine:
NOTE: When you remove the ACL housing, do not
disconnect the IAT sensor connector
After turning the idle adjusting scrow 1/2-turn'
check the idle speed again. lf it is out of spec, turn
the idle adjusting screw 1/2-turn agaan'
NOTE: Do not turn the idle adjusting screw more
than 1/2-turn without checking the idle speed'
ldle the engine for one minute with heater fan
switch at Hl and air conditioner on, then check the
idle speed.
ldle speed should be:
M/T810150 rpm
A/T. CvT810 t 50 rpm (in El or E Position)
NOTE:
. Do not turn the idle adjusting screw when the air
conditioner is on.
. lf the idle speed is not within specification. see
Symptom Chart on page 11-84 (cont'd)
11-221

ldle Control System
ldle Speed Setting (cont'dl
Inspeqtion/Adiustment
38 D16Y5 engine whh M/T,'99 - 00 81642 engine
NOTE: Before setting the idle speed, check the follow-ing items;- The MIL has not been reported on.- lgnition timing- Spark plugs- Air cleaner- PCV system
'1. Start the engine. Hold the engine at 3,000 rpm withno load (transmission in neutral) until the radiatorfan comes on, then let it idle.
Connect a tachometer.
Disconnect the IAC valve 2P connector and the EVAPpurge controlsolenoid valve 2P connector.
EVAP PURGECONTROLSOLENOID VALVE
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 conditions: headlights, blowerfan, rear defogger, radiator fan, and air conditionerare not operating.
ldl€ speed should be:
450 i 50 rpm
11-222
lf necessary, adjust the idle speed, by removrng lnecap and turning the idle adjusting screw.After adjusting the idle speed recheck the ignitlontiming (see section 23). lf it is out of spec, go backto step 4. |DLE
6. Turn the ignition switch OFF.
7. Reconnect the 2P connectors to the IAC valve andthe EVAP purge control solenoid valve, then do theECM reset procedure.
8. Restart and idle the engine with no-load conditionsfor one minute, then check the idle sDeed.ldle speed should bo:
USA:
D16Y5 engine: 670 i 50 rpm
81642 engine: 700 i 50 rpm
Canada:
81642 engine: 750 t 50 rpm
NOTE: lf the idle speed increases to 8lO t 50 rpm,this means the EVAP system is purging the canister.To stop the purging temporarily, raise the enginespeed above 1,000 rpm with the accelerator pedal,
then slowly release the pedal.
9. ldle the engine for one minute with headlights(Low) ON. and check the idle speed.
ldle speed should be:
750 i 50 rpm
10. Turn the headlights off. ldle the engine for oneminute with heater fan switch at Hl and air condi-tioner on, then check the idle soeed.ldls speed should be:
810 t 50 rpm
lf the idle speed is not within specification, seeSymptom Chart on page 11-84.

\
I
'98 - 0O D16Y5 ongine with CvT
Adjust the idle speed using a Honda PGM Tester if pos-
sible. lf not, use the following procedure:
NOTE:
. Leave the IAC valve connected.
. Before s€tting the idle speed, check the following
rtems:- The MIL has not been reported on.
- lgnition timing
- Spark Plugs- Air clean€r
- PCV svstem
'1. Connect a tachometer.
2. Stan the engine. Hold the engine at 3,000 rpm w'th
no load (transmission in E or E] position) until the
radiator Jan comes on, then let it idle.
3. Check the idle speed under no-load conditions:
head lights, blower fan, rear defogger, radiator fan,
and air conditioner are not operatlng.
ldlo spaod ehould bo: 700 t 50 rpm
. lf the idle speed is within the specification, the
procedure is comPlete.
. lf the idle sDeed is out of specitication, 9o to step 4'
4. tf the idle speed is 810 1 50 rpm, this means the
EVAP system is purging the canister. To stop the
purging temporarily, raise the engine speed above
l,OO0 rgm with the accelsrator pedal. Slowly release
the pedal. and rscheck the idl€ speed.
. tf the idle speed is within the specificstion, the
Drocedure is comPlete.
. lf the idle sp€ed is out of spocification, go to step 5.
5. Disconnect th€ EVAP purgs control solenoid valve
2P connector.
EVAP PURGECONTROL
6. Remove the cap and turn the idle adiusting screw
1/2-turn clockwise or counterclockwlse
IDLE
7.After turning the idle adjusting screw 1/2-turn, check
the idl€ speed again. lf it is out of spec, turn the idle
adjusting screw 1/2-turn again.
NOTE: Do not turn the idle adjusting screw more
than 1/2-turn without checking the idle speed.
Turn the ignition switch OFF. Reconnect the EVAP
purge control solenoid valve 2P connector' then do
the ECM reset Procedure.
Start the engine. ldle the engine for one minute with
heater fan switch at Hl and air conditioner on, then
check the idle speed.
ldle spaed should be:
810 t 50 rpm (in El or E Posiiion)
lf the idle speed is not within specification, see
Svmptom Chart on Page 11-84.
9.
SOLENOID VALVE
11-223