
ECM Data
You can retrieve data from the ECI\4 by connecting the OBD ll scan tool or the Honda PGM Tester to the data link
connector (DLC). The items listed in the table below conform to SAE recommended practice. The Honda PGM Tester
also reads data beyond that recommended by SAE to help you find the causes of intermittent problems.
The "operating values" listed are approximate and may vary depending on the environment and the individual
vehicle.
Unless noted otherwise, "at idle speed" means idling with the engine completely warmed up in the neutral position,
and the A,/C and all
Diagnostic
Trouble Code(DTC}
lf the ECM delects a problem, it will store it as a code
consisting of one letter and four numbers. Depending on
the problem, an SAE-defined code (Poxxx) or a Honda,
defined code {P1xxx) will be output to the tester.
The ECI\4 computes engine speed from the signals sent
from the crankshaft position (CKP) sensor. This data is
used for determining the time and amount of injected fuel.
detected, there is no
ourpul.
lf no problem is YES
Nearly the same as
tachometer indication
At idle speed;
The ECM converts pulse signals from the vehicle speed
sensor (VSS).Nearly the same as
speedometer
indication
Manifold
Absolute
Pressure(MAP)
The absolute pressure caused in the intake manifold by
engine load and speed.
With engine stopped: YES
Nearly the same as
almospnenc pressure.
At idle speed: about
20 4'1 kPa(150 310 mmHg,
6- 12 in.Hq).0.7 1.3 V
The ECT sensor converts coolant temperature into voltage
and signals the ECM. The sensor is a thermistor whose
internal resistance changes with coolant tempetature. The
ECM uses the voltage signals from the ECT sensor to
determine the amount of injected fuel.
With cold engine:
Same as ambient
temperature and IAT
With engine warmed
up; about 116 2'12"F
100'c).0.5-0.8 v
Air Fuel Ratio The A,/F sensor detects the oxygen content in the exha ust 0.0 - 1 .25 V(Ay'F) Sensor. gas and sends voltage signals to the Eclvl, Basedonthese 8.0 11.0mA(PGM(Sensor 1) signals, the ECM controls the airlfuel ratio. When the I Tester)
oxygen content is high (that is, when the ratio is leaner At idle speed:
than the stoichiometric ratio), the voltage signal is Iower. about 0.1 0.9 V
When the oxygen content is low (that is, when the ralio is
richer than the stoichiometric ratio). the voltage signal is
higher. The A'lF sensor signals are electrical current that
are indicated as voltaqe on the
The HO2S detects the oxygen content in the exhaust gas
and sends voltage signals to the ECM. Based on these
signals, the ECM controls the airlfuel ratio. When the
oxygen content is high (that is, when the ratio is leaner
than the stoichiometric ratio), the voltage signal is lower.
When the oxygen content is low (that is, when the ratio is
richer than the stoichiometric ratio), the voltage signal is
Secondary
Heated
Oxygen
Sensor(Secondary
H02S,
Sensor2)
0.0 1.25 V NO
At idle speed:
about 0.1 0.9 V
(cont'd)
11-13

PGM-FI System
(
(
(
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
\
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.
\

DTC P0108: MAP Sensor Circuit High Voltage
'1. Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on,
then let it idle.
2. Check the MAP with the scan tool.
le about 101 kPa (780 nmHg, 30 in.Hg) ot highet,
or about 2.9 V or higher indicated?
YES Go to step 3.
NO-lntermittent failure, system is OK at this time.
Check for poor connections or loose terminals at
the MAP sensor and at the ECM.I
3. Turn the ignition switch OFF.
4. Disconnectthe MAP sensor 3P connector.
5, Connect MAP sensor 3P connector terminals No. 2
and No. 3 with a jumper wire.
MAP S€NSOR 3P CONNECTOR
MAP{GRN/REO}SG1 (GRN/WHTI
JUMPER WIRE
Wire side of female terminals
6. Turn the ignition switch ON (ll).
7. Check the MAP with the scan tool.
ls about 101 kPa (760 mmHg,30 in.Hg) ot higher,
or about 2.9 V or higher indicated?
YES-Go to step 8.
NO Replace the MAP sensor.I
8. Remove the jumper wire.
123
9. Measure voltage between MAP sensor 3P
connector terminals No. 1 and No. 3.
MAP SENSOR 3PCONNECTOF
vccl{YEL/RED) l,lo cll.l.rl
I lsct
d) l{GRN/wHrr
YIilll
Wire side of female lerminals
ls there about 5 V?
YES Go to step 10.
NO Repair open in the wire between the ECM
(A1 1 ) and the MAP sensor.I
Turn the ignition switch OFF.
Connect ECM connector terminals A11 and A19
with a jumper wire.
ECM CONNECTOR A {31PI
Wire side of fema e te.minals
Turn the ignition switch ON (ll).
Check the MAP with the scan tool.
ls about 101 kPa (760 mmHg, 30 in.Hg) or higher,
or about 2.9 V ot higher indicated?
YES Update the ECM if it does not have the lalest
software, or substitute a known-good ECM, lhen
recheck (see page 1 1-6). lf the symptom/indication
goes away with a known good ECM, replace the
original ECM.I
NO-Repair open in the wire betlveen the ECI\il
(A19) and the MAP sensor.I
10.
11.
JUMPER WIAE
11-53

PGM-FI System
a
DTC Troubleshooting (cont'dl
DTC Pl128: MAP Sensor Signal Lower Than
Expected
1. Turn the ignition switch ON (ll).
2. Check the MAP with the scan tool.
ls 54.1 kPa(406mmHg, 16.0in.Hg), 1.6 V, or
higher indicated?
YES- Intermittent failure. system is OK at this
time.I
NO Replace the MAP sensor.l
11-54
\
\
DTC Pl129: MAP Sensor Signal Higher Than
Expected
1. Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on,
then Iet it idle.
2. Check the MAP with the scan toot.
ls 36.9 kPa (277 mmHg, 10.9 in.Hg), 1.1 V , or less
indicated?
YES- lntermittent failure, system is OK at this
time.l
NO Replace the MAP sensor.l
\

18.Remove the VTEC oil pressure switch (A) and
installthe specialtools as shown, then reinstall the
VTEC oil pressure switch.
07406-0070300
\lsl
t:={
R
07406-0020201 ot07MAJ-PY,lo11A and07MAJ-PY40120
A22 N.ml2.2kgt.m,16 rbf.ft)
19.
20.
21.
22.
07NAJ-P07010A
Reconnect the VTEC solenoid valve 2P connector
and VTEC oil pressure switch 2P connector.
Connect a tachometer or OBD ll scan tool/Honda
PGM Tester to the DLC.
Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on.
Checkthe oil pressure at engine speeds of 1,000
and 2.000 rpm. Keep the measuring time as shon
as possible {less than 1 minute) because the engine
is running with no load.
ls the oil ptessure below 49 kPa (0.5 kgf/cnf,
7 psi)?
YES Go to step 23.
NO Inspect the VTEC solenoid valve (see page 11-'t28l.a
23.
24.
25.
26.
Turn the ignition switch OFF.
Disconnect the VTEC solenoid valve 2P connector.
Aftach the battery positive terminalto VTEC
solenoid valve 2P connector terminal No. 2.
Start the engine, then connect the battery negative
terminalto VTEC solenoid valve 2P connector
terminal No. 1, and check the oil pressure at an
engine speed of 3,000 rpm.
ls the oil pressure above 390 kPa (4.0 kgt/crtf ,
57 psi)?
YES Go to step 27.
NO Inspectthe VTEC solenoid valve (see page I1-
12Al.a
27. With the battery terminals still connectedtothe
VTEC solenoid valve connector, measure voltage
between ECM connector terminal 89 and bodv
oround.
ECM CONNECTOR B {24P)
ls there battery voltage above 4,000 tpm?
YES Go to step 28.
NO-Replace the VTEC oil pressure switch (see
page 11'128).1
Turn the ignition switch OFF.
Disconnect the battery terminals from the VTEC
solenoid valve terminal connector.
(cont'd)
28.
29.
Wire side of female terminals
11-125

Fuel Pressure Test
Special Tools Required. Fuel pressure gauge 07406-0040004. Fuel pressure gauge sel 07ZAJ-S5A0100
1. Relieve the fuel pressure (see page 1'1-144).
2. Disconnect the quick-connect fitting (A). Aftach the
fuel pressure gauge set and fuel pressure gauge.
Start the engine and let it idle.
. lf the engine starts, goto step 5.. lf the engine does not start, goto step 4.
Check to see if the fuel pump is running: listen to
the fuel fill port with the fuel fill cap removed. The
fuel pump should run for 2 seconds when the
ignition switch is first turned on.
. lf the pump runs, go to step 5.. lf the pump does not run, do the fuel pump circuit
troubleshooting (see page 1 1-1 41 ).
Read the pressure gauge. The pressure should be
320-370 kpa (3.3-3.8 kgf/cm', a7-52 psi)
. lf the pressure is OK, the test is complete.. lf the pressure is out of specification, replace the
fuel pressure regulator and the fuel filter (see
page 11-152), then recheck the fuel pressure.
5.
11-145

Fuel Supply System
{Fuel Pressure Regulator
Replacement
Remove the fuel pump (see page 1 1-153).
Remove the fuel pressure regulator (A).
Installthe part in the reverse order of removal witha new o-ring (B).
1.
2.
11-152
Fuel Filter Replacement
The fuel filter should be replaced whenever the fuelpressure drops belowthe specified value {270 320 kpa,2.8 3.3 kgf lcm', 40 47 psi), after making sure that thefuel pump and the fuel pressure regulator are OK.
1. Remove the fuel pump(seepagell-'153).
2. Remove the
Install in the reverse order of removalwith a new
base gasket (B) and a new o-ring (C), then check
these items:
' When connecting the wire harness, make sure
the connection is secure and the terminal (D) is
firmly locked into place.. When installing the fuel gauge sending unit iE),make sure the connection is secure and the
connector is firmly locked into place. Be carefulnot to bend or twist it excessively.
\
fuel filter (A).
@-to
ReIJ
e"^AR^ ...\e @n-)
gs
sg

28.
29.
ls thete continuity?
YES-Go to step 28.
NO-Replace the EVAP canister vent shut valve (A)
and o-ring (B).1
Disconnect ECM connector E (31P).
Check for continuity between EVAP canister vent
solenoid valve 2P connector terminal No. 2 and
body ground.
EVAP CANISTER VENT SHUTVALVE 2P CONNECTOR
Wire side o{ female terminals
ls there continuity?
YES-Repair short in the wire between the EVAP
canister vent shut valve and the ECM (E21).1
NO Update the ECM if it does not have the latest
soflware, 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
30.
Vacuum Hoses and Connections Test
Do the fuel tank vapor control valve test (see page
1 1-187).
ls the fuel tank vapot control valve OK?
YES-Go to step 31.
NO Replace the fueltank vapor control valve.l
Tighten the fuel cap 3 "clicks", then monitorthe
FTP sensor readings with the Honda PGM Tester.
Start the engine. and let it idle for 5 minutes.
Check the FTP sensor readings.
ls the reading above 0.5 kpa (4 mm Hg, 0.16 in.
Hg) pressure, or about 3 V?
YES 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 ECfvl, replace the
original ECM.t
NO Check the following parts for leaks:l
. Fueltank (A)
. Fuel fill cap (B)
. Fuel fill pipe (C)
. Fueltank vapor control valve(D). Fueltank vapor recirculation valve (E)
. Fueltank vapor recirculation tube (F)
. Fueltank vapor signaltube (G)
. Fueltank vapor control venttube(H). FTP sensor (J)
- Repair or replace any leaking parts.
5t.
11-179