2002 HONDA CIVIC ground

Fuel and Emissions Systems
System Descriptions (cont'dl
ECM lnputs and Outputs at Connector E (31P}
L
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1iMoFPR
2sr-{]zs3LG34SG3
6$1025HTC
1M RLY
8AFSHTCR
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14FTP15ELD
16EPSLD
18ACC20Z/VBS21VSV
22BKSW23K-LINE24SEFMJ26NEP
21rMoCD
29scs30WEN31MIL
Wire side of female terminals
NOTE: Standard battery voltage is '12 V.
TerminalnumberWire colorferminal nameDescription Signal
GRNI/ELIMO FPR (IMMOBILIZERFLJEL PUMP RELAYIDrives PGM Fl main relay 20Vfor2 seconds after turning ignition switch ON{ll). then batterv voltaoe2WHT/REDSHO2S (SECONDARYHEATED OXYGEN SENSOR(SECONDARY HO2S),SENSOR 2r
Detects secondary HO2S{sensor 2) signalWith throttle Jully opened from idle with fullywarmed up engine: above 0.6VWith throttle quickly closed: below 0.4 V
3BRN/YELLG3 (LOGIC GROUND)cround forthe ECM/PCMcontrolcircuitLess than 1.0 V at all times
4PNKSG3 {SENSOR GBOUND)Sensor oroundLess than 1.0 V at all times5YEUELUVCC3 {SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON (ll): about 5 VWith ionition switch OFF: about 0 V6BLKATr'HTSO25HTC (SECONDARYHEATED OXYGEN SENSOR(SECONDARY H02S)HEATER CONTROL)
Drives secondary HO2SheaterWith ignition switch ON (ll): baftery voltageWilh fullv warmed up engine running: dul,controlled
1REDA/ELMRLY (PGM.FI MAINRELAY}Drives PGM-Flmain relay 1Power source forthe DTCWith ignition switch ON (ll): about 0 VWith ignition switch OFF: battery voltage
IORNAFSHTCR {AIR FUEL BATIO(Iy'F)SENSOR HEATERCONTROL RELAY)
Drives air fuel ratio sensorheater relayWith ignition swirch ON {ll): 0 V
IYEUBLKIGl (IGNITION SIGNAL)Detecrs ignition signalWith ignition switch ON (ll): battery voltageWith iqnition switch OFF: about 0 V't4LT GRNFIP lFUEL TANKPRESSURE (FTP) SENSOR)Detects FTP sensor signalWith ignition switch ON (ll) and fuel fill cap open:about 2.5 VGRN/REDELD (ELECTRICAL LOADDETECTOF)Detects ELD signalWith ignition swjtch ON itt):aOoutO.t V l-gV(deDendino on electrical load)LT GRN/8LKEPSLD (ELECIRICALPOWEB STEEBING LOADDETECT)
Detects Power steering loadsrgnalAt idle with steering wheel in straight aheadposition: about 0 VAt idle with steering wheelatfull lock: momentary
'18REDACC (Ay'C CLUTCH RELAY)Drives P,/C clutch relayWith compressor ON: about 0 VWith comoressor OFF: batterv voltaoe
11-22
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Fuel and Emissions Systems
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System Descriptions (cont'd)
ldle Control System
When the engine is cold, the Ay'C compressor is on, the
transmission is in gear, the brake pedal is pressed. thepower steering load is high, or the alternator is
charging, the ECIM controls current to the ldle Air
Control (lAC) valve to maintain the correct idle speed.
Refer to the System Diagram to see the functional
layout of the system.
Brake Pedal Position Switch
The brake pedal position switch signals the ECM when
the brake pedal is oressed.
Electrical Power Steering (EPS) Senser
The EPS sensor signals the ECM when the power
steering load is high.
ldle Air Control llACl Valve
To maintain the proper idle speed, the IAC valve
changes the amount of air bypassing the throttle body
in response to an electrical signal from the ECM.
From AIR To INTAKECLEANER MANIFOLD
IAC VALVE
11-32
Fuel Supply System
Fuel Cut-off Control
During deceleration with the throttle valve closed,
current to the injectors is cut off to improve fuel
economy at engine speeds over 1,030 rpm. Fuel cut-off
action also occurs when engine speed exceeds
6,900 rpm, regardless of the position of the throttle
valve, to protect the engine from over-rewing. When
the vehicle is stopped. the ECM cuts the fuel at engine
speeds over 6,500 rpm.
Fuel Pump Control
When the ignition is turned on, the ECM grounds the
PGM-Fl main relay which feeds current to the fuel pump
for 2 seconds to pressurize the fuel system, With the
engine running. the ECM grounds the PGM-Fl main
relay and feeds current to the fuel pump. When the
engine is not running and the ignition is on, the ECI\4
cuts ground to the PGM-Fl main relay which cuts
current to the fuel pump.
PGM-FI Main Relay 1 and 2
The PGM-Fl main relay consists of two separate relays.
Relay 1 is energized whenever the ignition switch is ON(ll) to supply battery voltage to the ECM power to the
injectors, and power for relay, Relay 2 is energized to
supply power to the fuel pump for 2 seconds when the
ignition switch is turned ON (ll), and when the engine is
runnrng.

PGM-FI System
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DTC Troubleshooting
DTC P0107: MAP Sensor Circuit Low Voltage
1. Turn the ignition switch ON (lli.
2. Check the MAP with the scan tool.
ls about 101 kPa (760 mmHg,30 in.Hg)or 2.9 V
indicated?
YES Intermittent failu re, system is OK at this time.
Check for poor connections or loose terminals at
the MAP sensor and at the ECM.I
NO-Go to step 3.
3. Turn the ignition switch OFF.
4. Disconnect the MAP sensor 3P connector.
5. Turn the ignition switch ON (lll.
6. lvleasure voltage between MAP sensor 3P
conneclor terminals No. 1 and No. 3.
1.
sGl{GRN/WHTI
Wire s de of femaleterminais
ls there about 5 V?
YES Go to step 8.
NO-Go to step 7.
Measure voltage between EClvl connector
terminals 41 1 and 42'1.
ECM CONNECTOR A 13'IP}
MAP SENSOR 3P CONNECTOF
vccr{YEL/BED)
sGr{GRN/WHT}
11-52
Wire side of female terminals
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8.
ls there about 5 V?
YES-Repair open in the wire between the Eclvl(A21)and the MAP sensor.l
NO Update the ECM if it does not have the latest
software, or substitule a known-good ECM, then
recheck (see page 'l 1-6). lf the symptom/indication
goes away with a known-good ECfvl, replace the
original ECM.I
Check the MAP with the scan tool.
ls 2 kPa (15 mmHg,0.6 in.Hg) ot less or 0 V
ind icated?
YES-Go to step 9.
NO Replace the lvlAP sensor.l
Turn the ignition switch OFF.
Disconnect ECM connector A (31P).
Check for continuity between MAP sensor
connector terminal No. 2 and body ground.
MAP SENSON 3P CONNECTOA
ls therc continuity?
YES-Repair short in the wire between the ECM(A19) and the MAP sensor.l
NO Update the ECM if it does not have the latest
software, or substitute a known-good ECM, then
recheck (see page 11-6). lf the symptom/indication
goes away with a known-good ECM, replace the
original ECM.I
9.
'10.
11.
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4.
DTC P0112: IAT Sensor Circuit Low Voltage
1. Turn the ignition switch ON (ll).
2. Check the IAT with the scan tool.
ls 302'F (150'C) or highet (or H-Limit in Honda
node of PGM Tester), ot 0 V indicated?
VES-Go to step 3.
NO Go to step 8.
Disconnect the IAT sensor 2P connector.
Check the IAT with the scan tool.
ls 302'F(150'C)or higher (or H-Limit in Honda
mode of PGM Testet), ot 0 V indicated?
YES-Go to step 5.
NO- Replace the IAT sensor.I
Turn the ignition switch OFF.
Disconnect ECM connector B (24P).
Check for continuity between IAT sensor 2P
connector terminal No. 2 and body ground,
IAT SENSOR2P CONNECTOR
,^ ,lr 2lt-l-----Tr---IAT_t{RED/YELI
II
Wire side of female terminais
ls there continuity?
YES Repair shon in the wire between the ECM
(B'17) and the IAT sensor.l
NO Update the ECM if it does not have the latest
software, or substitute a known-good ECM, then
recheck (see page 11-6). lf the symptom/indication
goes away with a known-good ECM, replace the
original ECM.I
5.
6.
7.
8. Check the temperature reading on the scan tool.
Be aware that if the engine is warm, the reading
will be higher than ambient temperature. lI the
engine is cold, the IAT and ECT will have the same
va lue.
ls the correct ambient temperature indicated?
YES lntermittent failure, system is OK at this time
Check for poor connections or loose terminals at
the IAT sensor and at the ECM.I
NO Replace the IAT sensor.l
11-55

11. At the wire harness side, check for continuity
between TP sensor 3P connector terminal No, 2
and body ground.
TP SENSOR 3P CONNECTOR
1 1213
'PS
REO
Wire side ot Iemale terminals
ls thete continuity?
YES-Repair short in the wire between the ECM
{A15) and the TP sensor.ll
NO-Go to step 12.
Connect ECM connector terminal A15 to body
ground with a jumper wire.
ECM CONNECTOR A 131P)
1121345679
1011112tc68 19 t2021
2312428129130
,tf$,rr*, ] ;uueen wrne
Wire side oJ .female terminals
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12.
13. At the wire harness side, check for continuity
between TP sensor 3P connector terminal No. 2
and body ground.
TP SENSOR 3P CONNECTOR
(RED/BLX}
Wire side of female terminals
ls there continuity?
YES-Update the ECM if it does not have the latest
software, or substitute a known-good ECM, then
recheck (see page 11-6). lf the symptom/indication
goes away with a known-good ECM, replace the
original ECM.I
NO- Repair open in the wire between the ECM
(A15) and the TP sensor.l
14. lvleasure voltage between ECM connector
terminals 410 and A20.
ECM CONNECTOB A 131P}
vcc2(YEL/8LU)
Wire side of female terminals
ls there about 5 V?
YES Repair open in the wire betlveen the ECM
(A20) and the TP sensor.I
NO Update the ECM if it does nor have the latest
software, or substilute a known-good ECM, then
recheck (see page 1 1-6). lf the symplom indication
goes away with a known-good ECM. replace lhe
original ECM.I
123
TPS
11-61

PGM-FISystem
3.
DTC Troubleshooting (cont'dl
DTC P0141: Secondary HO2S (Sensor 2l
Heater Circuit Malfunction
1. Reset the ECM (see page 1 l-4)
2. Start the engine.
ls DTC P0141 indicated?
YES-Go to step 3.
NO-lntermittent failure, system is OK at this time.
Check for poor connections or loose terminals at
the secondary HO2S (Sensor 2) and at the ECM.I
Turn the ignition switch OFF.
Disconnect the secondary H02S (Sensor 2) 4P
connecror.
At the secondary HO2S (Sensor 2) side, measure
resistance between H02S 4P connector terminals
No.3 and No. 4.
SECONDARY HO2S (SENSOR 21 4P CONNECTOR
Wire side ol lemale terminals
ls there about 3.3 Q ?
YES Go to step 6.
NO- Replace the secondary HO2S (Sensor 2). t
5.
11-68
6. Check for continuity between body ground and
secondary H02S (Sensor 2) 4P connector terminals
No.3 and No. 4 individually.
SECONDARY HO2S {SENSOR 21 4P CONNECTOR
Wire side of female terminals
ls there continuity?
YES- Replace the secondary HO2S (Sensor 2).1
NO-Go to step 7.
Turn the ignition switch ON (ll).
Measure voltage between secondary H02S 4P
connector terminals No. 3 and No. 4,
SECONDARY HO2S (SENSOR 2l ilP CONNECTOR
t
7.
8.
9.
10.
s02sHTc{BLK/WHTIIG1 (BLK/ORN}
Terminal side of male terminals
ls there battery voltage?
YES Go to step 9.
NO Go to step 12.
Turn the ignition switch OFF.
Disconnect ECM connector E {31P)

1 1. Check for continuity between ECM connector
terminal E6 and body ground.
ECM CONNECTOR E {31PI
Wire side o{f Iemale terminals
ls therc continuity?
YES-Repair short in the wire between the ECM
(E6) and the secondary HO2S (Sensor 2).1
NO-Update the ECM if it does not have the latest
soflware, or substitute a known-good ECM, then
recheck (see page 1 1-6). lf the symptom/indication
goes away with a known-good ECM, replace the
original ECM.I
Measure voltage between secondary HO2S
(Sensor 2) 4P connector terminal No. 4 and body
g rou nd.
SECONDARY HO2S {SENSOR 2I 4P CONNECTOR
tFff I
l[faJl--ro'14 | IBLK/OFN)
YI
Terminal side of male terminals
ls there battety voltage?
YES Go to step 13.
NO-Checkthe No. 4 ACG (10A) fuse in the under-
dash fuse/relay box. lf the fuse is OK, repair open in
the wire between the secondary HO2S (Sensor 2)
and No. 4 ACG (10A) fuse.l
13.
14.
t5.
to.
Turn the ignition switch OFF.
Reconnect the secondary HO2S (Sensor 2) 4P
connector.
Disconnect ECM connector E (31P).
Turn the ignition switch ON (ll).
Measure voltage between ECM connector terminal
E6 and A5.
ECM CONNECTORS
A (31 P)
E {31 P}
Wire side ot female terminals
Is there 0-1 V or less?
YES-Repair open in the wire between the ECM
(E6) and the secondary HO2S (Sensor 2). !
NO Update the ECM if it does not have the latest
software, or substitute a known-good ECM, then
recheck (see page 1 1-6). lf the symptom/indication
goes away with a known-good ECM, replace the
original ECM. a
17.
11-69

16.Test-drive the vehicle for several minutes in the
range of the freeze data or under various
conditions if there was no freeze data.
Check for a DTC or a Temporary DTC with the scan
Tool.
ls DTC or Temporary DTC P0301, P0302, P0303
or P0304 indicated?
YES Go to step 18.
NO lntermittent misfire due to bad contact at the
injector connector (no misfire at this time). Make
sure the injector connection is secure. Check for
poor connections or loose terminals at the
injector.l
Determine which cylinder(s) had the misfire.
Does the misf ire occur in the cylinder where the
i njector w as exchanged ?
YES- Replace the faulty injector.I
NO-Go to step 19.
Turn the ignition switch OFF.
Disconnect the ignition coil 3P connector from the
problem cylinder.
Turn the ignition switch ON (ll).
't7 .
18.
19.
20.
22. Measure voltage between ignition coil 3P
connector terminal No. 3 and body ground.
IGNITION COIL 3P CONNECTOR
Wire side ol female terminals
ls there battery voltage?
YES-Go to step 23.
NO Repair open in the wire between the No. 1
IGN COIL (15A)fuse and the ignition coil.I
Turn the ignition switch OFF.
Check for continuity between ignition coil 3P
connector terminal No. 2 and body ground.
IGNITION COIL 3P CONNECTOR
Wire side ot female terminals
ls there continuity?
YES Go to step 25.
NO Repair open in the wire between the ignition
coiland G101.1
Disconnect ECM connector A {31P)
23.
24.
(cont'd)
11-73