PGM-FI System
System Description
INPUTS
CKP/TDC/CYP Sensor
CKF Sensor
MAP Sensor
ECT Sensor
IAT Sensor
TP Sensor
Primary HO2S
Secondary H02S
vss
KS*5
BARO Sensor
ELD*6
Starter Signal
ALT FR Signal
Air Conditioning Signal
Ay'T Gear Position Signal*1
Baftery Voltage (lGN.1)
Brake Switch Signal
PSP Switch Signal
Fuel Tank Pressuae Sensor*4. *5
Countershaft Speed Sensor*1
Mainshaft Speed Sensor*r
OVER-DRIVE Switch Signal*s
ENGINE CONTROL MODULE (ECM)/
POWERTRAIN CONTROL MODULE (PCM) OUTPUTS
|iuel 1"j""- Th,rhg ""d Drrafr";-l
Et*-.nt"tdt"cont.orl
to,r*,c;;trffi;]
l.----.---:. .Lrgnrnon |lmrng Lonrror I
Ecir/PcM B*k',p Fr""il]
m;"t-ll-r*'io*l
Fuel Injectors
PGM-Fl Main Relay (Fuel Pump)
MIL
IAC Valve
Ay'C Compressor Clutch Relay
Radiator Fan Relay
Condenser Fan Relay
ALT
tcM
EVAP Purge Control Solenoid
Valve
Primary HO2S Heater
Secondary H02S HeaterEVAP Bypass Solenoid Valve*a *5
EVAP Control Canister Vent Shut
DLC
Lock-up Control Solenoid Valve*l
Shift Control Solenoid Valve*1
Ay'T Clutch Pressure Control
Solenoid Valve*1
D4 Indicator Light'1 *3, *a
D Indicator Light,l *5
OVER-DRIVE OFF Indicator
Lighl*t *:
*1: A/T {3:'97 model'2: M/f +4:'98 model*5: '99 - 00 models"6: USA
PGM-Fl System
The PGM-Fl system on this model is a sequential multiport fuel injection system.
Fuel iniecior Timing and Duration
The ECM/PCM contains memories for the basic discharge durations at various engine speeds and manifold pressure. The
basic discharge duration, after being read out from the memory, is further modified by signals sent from various sensors
to obtain the final discharge duration.
ldle Air Control
ldle Air Control Valve (lAC Valve)
When the engine is cold, the Ay'C compressor is on, the transmission is in gear, the brake pedal is depressed, the P/S load
is high, or the alternator is charging, the ECM/PCM controls current to the IAC Valve to maintain the correct idle speed.
lgnition Timing Control
o The ECM/PCM contains memories for basic ionition timing at various engine speeds and manifold air flow rates.
lgnition timing is also adjusted for engine coolant temperature.
. A knock control system was adopted which sets the ideal ig nition timing for the octane rating of the gasoline used.*s
Other Control Funstions
1. Starting Control
When the engine is started. the ECM/PCM provides a rich mixture by increasing fuel injector duration.
2. Fuel Pump Control
. When the ignition switch is initially turned on (ll). the ECMiPCM suppli€s ground to the PGM-FI main relay that
supplies current to the fuel pump for two seconds to pressurize the fuel system.
. When the engine is running, the ECM/PCM supplies ground to the PGM-FI main relay that supplies current to the
fuel oumo.
. When the engine is not running and the ignition is on, the ECM/PCM cuts ground to the PGM-FI main relay which
cuts current to the fuel pump.
1 1-80
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ldle Control System
ldle Air Control llAC) Valve
The scan tool indicates Diagnostic Trouble Code (DTC) Pl508: A probtem in the ldle Air Controt flAC) varvecircuit.
The IAC Valve changes the amount of air bypassing the throttle body in response to a current signal from the ECM/PCM inorder to maintain the proper idle speed.
37 model;
IAC VALVE 2P CONNECTOR {C132}
,f rcp'# IYEL/BI.(II2f-1-d)
Y
Wir€ side of female terminals
PCM CONNECTOR A I32PI
tacvIBLK/BLU)
From AIR To INTAKECLEANER MANIFOLD
Wire side of female terminals
The MIL has beon .eport€d on.OIC Pl508 is sto.ed.
Problem veiification:1. Do the PCM Reset Procedure.2. Start the engine, and warm itup to normal operating tem-perature.
Inte.mittent failure, systcm b OKat thi3 time. Check tor poo. con-nections or loose wircs at C132(lAC v.lvel and at the PCM.
ls DTC Pl508 indicated?
Check lor an open in the wir6{lGPl lins}:1. Turn the ignition switch OFF.2. Disconnect the IAC valve 2Pconnector.3. Turn the ignition switch ON {ll).4. Measure voltage between bodyground and the IAC valve 2Pconnector term inal No.2.
Repair open in the wire trctwoontha IAC v!lv6 and the PGM-Flmain relly.
Chock for an opan o. short in thowi.e (lACv linel:1. Turn the ignition switch OFFand reconnect the IAC valve2P connector.2. Disconnect the PCM conneclorA (32P).
3. Turn the ignition switch ON {ll).4, Measure voltage betweenbody ground and PCM con-nector terminal A12.
{To page 1l-153)
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The MIL has boen r.ported on.DIC Pl 508 b 3tored.
Problem veritication:L Do the ECM/PCM Reset Pro-cedure.2. Start the engine, and warm itup to normal operating tem-perature.
Int€rmittent failure, systom is OKal lhis timo. Check lor poor con-nections or looro wirca at C132(lAc vrlvel and .t rho EcM/PcM.
ls DTC P1508 indicated?
Chock tor an open in the wir6llGPl linel:1. Turn the ignition switch OFF.2. Disconnect the IAC valve 2Pconnector,3. Turn the ignition switch ON (ll).4. Measure voltage between bodyground and the IAC valve 2Pcon nector termina I No, 2.
Repair opon in the wira botwoonthe IAC valve and tho PGM-FImain aalay.
Check tor an open or short in thewire (IACV linel:1. Turn the ignition switch OFFand reconnect the IAC valve2P connector.2. Disconnect ECM/PCM con-nector B {25P).3. Turn the ignition switch ON {ll}.4. Measure voltage betweenbody ground and ECM/PCMconnector terminal 823.
Ropair open or short in thg wirebetween tho ECM/FCM lB23l andthe IAC valve.
ls there battery voltage?
Check the IAC valve func,tion:Momentarily connect ECM/PCMconnector terminals 823 and 82with a jumper wire several times.
Does the IAC valve click?
Subslitute . known-good ECM/PCM .nd rechock. lf symptom/indication goes aw.y, replac.th€ original ECM/PCM.
ldle Air Control (lAC) Valve {cont'd}
'98 - 00 models:
IAC VALVE 2P CONNECTOR {C132I
F rcpt*l tYELrBLxlI2/'-- rf)
Y
Wire side ot fem.le terminals
ECM/PCM CONNECTOR B (25PI
Wire side of female torminals
258
9'to1l13t7
1920212223
tAcv(BLK/BLUIv
PG1{BLKI
12 | t3 4 58
910 111317
1920 | 121)22
tAcv(BLK/
BLU)JUMPER WIRE
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ldle Speed Setting
Inspoction/Adiustmont
37 modsl:
NOTE:
. Before setting the idle speed, check the following
items:- The MIL has not been reportsd on.- lgnition timing- Spark plugs
- Air cleaner- PCV system
. lcanada) Pull the parking brake lever up. Stan 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 or a Honda PGM Tester.
Disconnect the 2P connector from the ldle Air Con-
trol (lAC) valve.
IAC VALVE
lf the engine stalls, restart the engine with the accel-
erator pedal slightly depr6ss6d, Stabilize the rpm at
1,000, then slowly release the pedal until the engine
idles.
Check idling in no-load conditions: hsadlights,
blower fan, rear d€fogger, radiator fan, and air con-
ditioner are not operating.
ldle spood should b.:
{80 t 50 rpm {in Park or noutr.ll
IDLE
7.
Adjust the idle sp6ed,
idle adjusting screw.
if necessary, by turning the
Turn the ignition switch OFF.
Reconnect the 2P connector to the IAC valve, then
remove the BACK UP (RAD|Ol (7.5 Al fuse in the
under-hood fuse/rslav box for 10 seconds to reset
the PCM.
Restart and let the engine idle with no-load condi-
tions for one minute, then check the idle speed.
NOTE: (Canadal Pullthe parking brake lever up. Stan
the engine, then check that the headlights are off.
ldlo Ep€ed rhould be:
75O t 50 rpm (in P.rk or noutr.ll
Let the engine idl6 for one minute with the head-
lights (Low) ON, and check th€ idl€ speed.
ldle lpcod 3hould bo:
750 t 50 ]pm (in Park or nautlal)
Turn the headlights off. Let th€ engine idle for one
minute with the headlights (Low) ON, heater fan
switch at Hl and air conditioner on. then check the idle
sDeeo.
ldl. specd should b6:
7d) 1 50 rpm {in Park or nautral}
lf the idle speed is not within specification, see the
symptom chart on page 11-64. (cont'd)
1 1-169
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ldle Control System
ldle Speed Setting (cont'd)
38 - 0O mod6l3:
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 with
no load (in Park or neutral) until the radiator fan
comes on, then let it idle.
Connect a tachometer.
Disconnect the IAC valve 2P connector and the EVAP
purge control solenoid valve 2P connector.
CONTROLSOLENOID VALVE
SOLENOID VALVE
lf the engine stalls, restart the engine with the accel-
erato. pedal slightly depressed. Stabilize the rpm at
1,000, then slowly release the pedal until the engine
idles.
Che€k the idle in no-load conditions: headlights, blow-
er fan, rear defogger, radiator fan, and air conditioner
are not operating,
ldle speed should bo:
480 t 50 rpm {in PErk or noutrall
11-170
lf necessary, adjust the idle speed, by turning the
idle adjusting screw.
After adjusting the idle speed, recheck the ignition
timing (see section 4). lf it is out of spec, go back to
steo 4.tDt.E
6. Turn the ignition switch OFF.
7. Reconnect the 2P connectors to the IAC valve and
the EVAP purge control solenoid valve, then do the
ECM/PCM reset procedure.
8. Restart and idle the engine with no-load conditions
for one minute, then check the idle speed.
ldle speod should be:,98 model:
750 t 50 rpm tin Park or neutral)'9!l - 00 modsls:
730 i 50 lpm lin Psrk or neutral)
NOTE: lf the idle speed increases to 780 t 50 rpm(770 1 50 rpml*, this means the EVAP system is
purging the canister. To stop the purging temporari-
ly, raise the engine speed above 1,000 rpm with the
accelerator pedal, then slowly release the pedal.*: '99 - 00 models
9. Let the engine idle for one minute with the head-
lights (Low) ON, and check the idle speed.
ldle speed should be:
38 mod6l:
750 f 50 rpm (in Palk or neutrall'99 - 00 modols:
730 t 50 rpm (in Palk or neutral)
10. Turn the headlights off. Let the engine idle for one
minute with the heater fan switch at Hl and air con-
ditioner on, then check the idle speed.
ldls spqed should be:'98 model:
780 t 50 rpm (in Park or neutrall'99 - 00 mod€ls:
7701 50 rpm lin Park or neutral)
lf the idle speed is not within specification. see the
Symptom Chart on page 11-64.
ADJUSTING
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lnstellation
1. Open the throttle valve fully, then install the throttle
cable in the throttle linkage, and install the cable
housing in the cable bracket.
97 - 98 modols:
THRoTTLE LINKAGE CABLE
INNER CABLE
- (Xl modols:
LOCKNUT
'99
2.Sta.t 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.
Hold the cable sheath, removing all slack from the
cable.
Set the locknut on the cable bracket.
Adiust the adjusting nut so that its free play is 0 mm.
Rimove the cable sheath from the throttle bracket,
reset the adjusting nut and tighten the locknut.
ADJUSTING
BRACKET
'97 - 98 modals:
lhere should beno clearance.
AD.'USTING NUT
'99 - 00 modeb:
CABLEBRACKET
9.8 N.ml'1.0 kgt'm,7.2 tbr.ft)
9.8 N.m(1.0 kg{.m,7.2lbllrl
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EVAP PURGE CONTROL SOLENOID VALVE DUTY CONTROLLED AFTER
STARTING ENGINE
ENGINE COOLANT TEMPERATURE ABOVE 154"F (68'C)
Evaporative Emission (EVAP) Controls
Description:
The evaporative emission controls are designed to minimize the amount of fuel vapor escaping to the atmosphere. The
system consists of the following components:
A. Evaporative Emission (EVAPI Control Canister
An EVAP control canister is used for the temporary storage of fuel vapor until the luel vapor can be purged from the
EVAP control canister into the enqine and burned.
B. Vapor Purge ConirolSystem
EVAP control canister purging is accomplished by drawing fresh air through the EVAP control canister and into a pon
on the intake manifold. The purging vacuum is controlled by the EVAP purge control solenoid valve.
C. Fuel Tank Vapor Control System
When fuel vapor pressure in the fuel tank is higher than the set value of the EVAP two way valve, the valve opens and
regulates the flow ot fuel vapor to the EVAP control canister.
'97 model:
EVAPPURGECONTROL
VALVEFromNo. 15BLK/ /ALTERNATORYEL I sP SENSOR r7.s At(in the under-dashfuse/relay box)
VARIOUSSENSORFEESH AIF
BLK
I
FUEI- TANK
(cont'd)
11-203
INTAKE MANIFOLD
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'97 model:
The scan tool indicates Diagnostic Trouble Code (DTC) P0441: Evaporative Emission (EVAP) control system
insufficient purge flow.
Description
By monitoring the purge line vacuum with the MAP sensor, the PCM can detect insufficient EVAP control system purge
flow.
Possiblo Cause
. EVAP Purge Control Solenoid Valve
. EVAP Purge Control Solenoid Valve Circuit
. EVAP Control Canister
. Vacuum Lines
. PCM
Troubleshooting Flowchart
EVAP PURGE CONTROL
SO1TNOID VALVE 2P
CoNNECTOR (C108)
(v)
YL
Wire side of female
termrnals
(cont'd)
11-205
Th€ MIL has b€en reooited on.DTC P0441 is .tored.
Problem verificationl1. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neut.al) untilthe radiator fan comes on.2. Do the PCM Reset Procedure.3. Connect the SCS service con-nector,4. Test drive under following con'ditions on the road.- without any electrical load- Transmission in @ or @position- Engine speed between1 ,2OO - 2,4OO rpfi.- Decelerate from 50 mph (80
km/h)to 15 mph (24 km/h)Intermittent trilure, sydern is OKat this time. Check for Door con-nections or loose wir€3 at C108
IEVAP purge control solonoidvalvol .nd at the PCM.
ls DTC P0441 indicated?
Check tor an open in the wire (lcl
linel:1. Turn the ignition switch OFF.2. Disconnect the EVAP purge
control solenoid valve 2P con-nector.3. Turn the ignition switch ON (ll).
4. Measure voltage between bodyground and the EVAP purge
control solenoid valve 2P con-nector terminal No. '1,
R€pafu open in thc wir6 b€tw€enthG EVAP purge control solenoidvalve and the No. 15 ALTEBNA-TOR SP SENSOR (7.5 A)fuse.
ls there batlery voltage?
(To page 11'206)
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