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Troubleshooting
ECM CONNECTOR {31P)
Engine Control Module Terminal Arrangement (cont'd)
ECM CONNECTOR C {31P)
235srsscs1112t31515t71A19
2A
Wire side of lemale terminals
NOTE: Standard battery voltage is 12 V.
TerminalnumbercolorTerminal namoD6scriptionSignal
1BLU/REDCKF P (CKF SENSOR P SIDE)Detects CKF sensor.With engine running: pulses
28LUCKP P (CKP SENSOR P SIDE)Detects CKP sensor.With engine running: pulses
3GRNTDC P {TDC SENSOR P SIDE)Detects TDC sensor,With engine running: pulses
YELCYP P (CYP SENSOR P SIDE)Detects CYP sensor,With engine running: pulses
5BLU/REDACS (AJC SWITCH SIGNAL)Detects A,/C switch signal.With A,/C switch ON: 0 VWith A,/C switch OFF: battery voltage
6BLUA/VHTSTS (STARTEB SWITCHSIGNAL)
Detects starter switch signal.With staner switch ON: battery voltageWith starter switch OFF: 0 V
7BRN,AiVHTSCS (SERVICE CHECKSIGNAL)Detects service check connectorsignal (the signalcausing a DTC;ndication).
With the co n nector con nected: 0 VWath the connector disconnected: about 5 V
8GRNAVHTK LINESends and receives OBD ll scantool and PGM tester signal.With ignition switch ON (ll): about 5 V
9YELFAS lFEEDBACK AT SIGNAL)Sends feedback signal for theTCM,At idle: about 5 VDuring shifting: momenlary change to 0 V
10WHT/BLU
VBU (VOLTAGE BACK UP)Power source for the ECMcontrolcircuit,Power source for the DTC
Battery voltage at all times
t1WHT/REDCKF M (CKF SENSOR I\4 SIDE)Ground for CKF sensor.
12BLUI/E LCKP M (CKP SENSOR M SIDE)Ground for CKP sensor.
WHT/BLUTDCM (TDC SENSOR M SIDE)Ground tor TDC sensor.
14CYPM (CYP SENSOR M SIDE)Ground for CYP sensor.
15*.BLU/BLKVTP SW (VTEC
PRESSUFE SWITCH)Detects VTEC pressure switchsr9nal.
With engine at low rpm:0 VWith engine at high rpmlbattery voltaqe
161,GRN
PSPSW (P/S OILPRESSURE SWITCH)Derecls PSP switch signal.At idle with steering wheel in straight aheadpositioni 0 VAt idle with steering wheelat full lock: batteryvoltage
17WHT/REDALTF (ALTERNATOR FRSIGNAL)Detects alternator FR signal.With fully warmed up engine running:0 V battery voltage (depending onelectrical load)
18ORNVSS (VEHICLE SPEEDSENSORiDetects VSS signal.With ignition switch ON (ll) and lrontwheels rotating: cycles 0 V- 5 V
19*3BLUAT CHK (A/T FI DATA LINE)Detects TCM data signal.With ignition switch ON (ll)i pulses
21*LT GRNBARO OUT (SAROMETRIC
SENSOR OUTPUT S!GNAL)Sends barometric sensor outputsrgnal,With ignition switch ON (ll): about 3 V(depending on barometric pressure)
27 x3GRYAFSB (A"/T FI SIGNAL B)Detects retard signal from theTCM,At idle: about 5 VDuring shifting: momentary changeto0V
28+1GRN/8LUA+SA (A/T FI SIGNAL A)Detects retard signal from theTCM.At idle: about 5 VDuring shifting: momentarV changeto0V
29+3LT GRN/BLKATPPN (A/T GEARPOSITION SWITCH)Detects A,/T gear position switchsrgnal-In E orE positionr 0VIn anv other position: battery voltage
*1: USA*2:818C1 engine*3: A/T*4: 818C1, 818C5 engines
PGM-FI System
System Description
ENGINE CONTROL MODULE (ECM)OUTPUTS
*1: USA*2: 818C1 engine*3: A,/T*4: 818C1, 818C5 engines
PGM-FI Sy3tem
The PGM-Fl system on this model is a sequential multiport fuel injection system.
Fuel lniector Timing and Duration
The ECM contains memories for the basic discharge durations at various engine speeds and manifold pressures. 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 Ai. Control Valve (lAC Valve)
When the engine is cold, the Ay'C compressor is on. the transmission is in gear (Ay'T only)the brake pedal is depressed, the
P/S load is high, or the alternator is charging, the ECM controls current to the IAC Valve to maintain correct idle speed.
lgnition Timing Control
. The ECM contains memories for basic ignition timing atvarious engine speeds and manifold pressures, lgnitiontiming
is also adjusted for engine coolant temperature.
. AKnockControl System isadoptedwhich sets the ideal ignition timing for the octane n um ber of gasoline used*r,
Other Control Functions
L Starting Control
When the engine is started, the ECM provides a rich mi{ure by increasing fuel injector duration.
2. Fuel PumD Control
. When the ignition switch is initially turned on, the ECM supplies 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 supplies ground to the PGM-FI main relay that supplies current to the fuel
DUmO.
. When the engine is not running and the ignition is on. the ECM cuts ground to the PGM-FI main relay which cuts
current to the fuel oumo.
INPUTS
TDc/CKP/CYP Sensor
CKF Sensor
MAP Sensor
ECT Sensor
IAT Sensor
TP Sensor
HO2S
VSS
BARO Sensor
ELD*1
Starter Signal
ALT FR Signal
Air Conditioning Signal
A,/T Gear Position Signal*3
Battery Voltage (lGN.1)
Brake Switch Signal
PSP Switch Signal*'
Knock Sensor*1
VTEC Pressure Switch*4
Fuel Tank Prssure Sensor
Fuel InjectorTiming and Duration
Electronic ldle Control
Other Control Functions
lgnition Timing Control
ECM Back-uD Functions
Fuel-lnjectors
PGM-Fl Main Relay (Fuel Pump)
MIL
IAC Valve
A,/C Compressor Clutch Relay
Radiator Fan Belay*1
Condenser Fan Relay
ALT*1
rcM
EVAP Purge Control Solenoid
Valve
H02S Heater
VTEC Solenoid Valve*'
IAB Control Solenoid Valve*,
EVAP Bypass Solenoid Valve
EVAP Control Canister Vent
Shut Valve
11-48
2.
1.
1.
2.
After the engine stans, the IAC valve opens for a certain time. The amount ol air is increased to raise the idle speed
about 150 - 300 rpm.
When the coolant temperature is low, the IAC valve is opened to obtain the proper fast idle speed. The amount of
bypassed air is thus controlled in relation to the engine coolant temperature.
IDLE SPEEDtrpm,
ENGINECOOLANT TEMPERATURE
140
50
104
40
-1 32
-20 0
176 ('F)
80 fcl
When the idle speed is out of specification and the scan tool does not indicate Diagnostic Trouble Code (DTC) P0505
or P'1508, check the following items:. Adiust the idle speed (see page '11-111)
' ALT FR signal (see page 11-101). Air conditioning signal {seepage'11-102)' Brake switch signal (seepagell-104)
. Starter switch signal (see page 11-1051. A,4 gear position signal (see page 1l 106) (A"/T)
. PSP switch signal (see page 11-108) (USA)
. Fast idle thermo valve (see page 11-110). Hoses and connections. IAC valve and its mounting O rings
ll the above items are normal, substitute a known-good IAC valve and readjust the idle speed (see page 'l I -1 1 l).
lf the idle speed still cannot be adjusted to specification (and the scan tool does not indicate DTC P0505 or P1508) after
IAC valve replacement, substitute a known-good ECM and recheck. lf symptom goes away, replace the original ECM.
11-97
Starter Switch Signal
This signals the ECM when the engine is cranking.
NOTEI. M/T:Clutch pedal must be depressed.. A,/T: Transmission in E or E position.
Wire sida of female terminals
Check for an opon or short in thcwi.. ISTS lin.l:Measure voltage between ECMconnector terminals C6 and Agwith the ignition switch in thostart position (lll).
Inspect the No.31 STARTER SIG-NAL (7.5 Alluse in the under-dashfuse/relay box,
ls there battery voltage?
- Repair 3hort in the wire be-tween tho ECM lc6l rnd theNo. 31 STARTER SIGNAL (7.sAl tus€ or the PGM-FI mainr€lay.- Roplace the No. 31 STARTERSIGNAL 17.5 Al fuso.
Starter switch signal b OK.
Ropair open in tho wire botwaonih6 ECM {CGl and the No, 3lSTARTER SIGNAL {7.5 Al fuse.
11-105
I
Fuel Supply System
Fuel Injector (cont'dlFuel Pressure Regulator
Description
The fuel pressure regulator maintains a constant fuel
pressure to the fuel injectors. When the difference
between the fuel pressure and manifold pressure
exceeds 3.0 kgf/cm' (294 kPa,43 psi) IB18C'1,818c5
engines:3.5 kglcm'(343 kPa,50 psi)l, the diaphragm is
Dushed uDward, and the excess fuel is fed back into the
fuel tank through the return line.
CLOSED:
INTAKEMANIFOLDVACUUM
I1{TAKEMANIFOLDVACUUM
DIAPHRAGM
< IFUEL INLET\-
\
OIAPHRAGM
/4_\T-J FUEL INLET
9.
10.
11.
7.
8.
1t
Slide new cushion rings onto the fuel iniectors.
Coat new O-rings with clean engine oil, and put
them on the fuel injectors.
Insert the injectors into the fuel rail first.
Coat new seal rings with clean engine oil, and press
them into rhe intake manifold.
To prevent damage to the O-rings, install the luel
injectors in the fuel rail first, then install them in the
intake manifold.
Align the center line on the connector with the mark
on the fuel rail,
FUEL RAIL
MARKINGS
13.
14.
15.
16.
Install and tighten the retainer nuts.
Connect the vacuum hose and fuel return hose to
the fuel pressure regulator.
lnstall the connectors on the fuel injectors.
Turn the ignition switch ON (ll). but do not operate
the starter. After the fuel pump runs for approxi'
mately two seconds, the fuel pressure in the fuel
line rises. Repeat this two or three times, then check
whether there is any fuel leakage.
FUEL RAIL
FUEL
F
I
Fuel Supply
PGM-Fl Main
System
Relay (cont'd)
\
lb
i
(From page 11 125)
- Reprir open or short in thewire between the PGM-FI mainrelay and the No. 31 STARTERSIGNAL {7.5 A} tuse.- RoDlace the No. 31 STARTERSIGNAL {7.5 A) fuse in theunder-dash luse/relav box,
Check for an open in the wire
{FLR line}:1. Turn the ignation switch OFF.2. Disconnect the ECM connector A (32P).
3. Check for continuity betweenthe PGM-FI main relay 7P con-nector terminal No. 1 and ECMconnector terminal A16-
Repair open in the wire betweenthe ECM (A161 and the PGM-FImein relay,ls there continuity?
Check for an open in the wires{lGPl, lGP2lines}:1. Reconnect the ECM connectorA (32P).
2. Reconnect the PGM-Fl mainrelay 7P connector.3. Turn the ignition switch ON {ll).4. Measure vo ltage betweenECM connector terminals A10and A11, and between A10and 424.
- Repaar open in lhe wir€ bet-ween the ECM 1A11, A24l andthe PGM-FI main relay.- Repldce the PGM-FI main relay.
ls there battery voltage?
Substitute a known-good ECMand recheck. It prescribed vohageis now available. roplace lhe o.ig-inalECM.
ls there 1.0 V or less?
Check the PGM-Fl main relaylsee page 11-124).
PGM.FI MAIN BELAY 7P CONNECTOR IC443I
FLR
FLR
Wire side of temale terminals
Check tor en open in the ECM:1. Turn the ignition switch OFF.2. Measure voltage betlveen ECMconnector termanals A16 andA10 when the ignition switchis first turned ON (ll) for two
IGRN/BLU}
o
1,2!t5i6
:cM CONNEi)TOR A I32P)
I23sl6a9to11
1215lor 17 18t920/22232a
25262l12329
PGl(8LKI
IGP 1
{YEL/BLK}
(
t356I
t5161t la192022
25a
IGP 2{YEL/BLKI
12 15 15 17 18 19 20 .r 22 23
Transmission Assembly
Removal
r@i Make surs iacks and safety stands sro placod propor-
ly (3ee s€ction 1).
. Apply parking brake and block resr whaeb 30 vohicle
will not roll off stands and hll on You whil6 working
under it.
CAUTION: Use fender covers to svoid damaging
paintod surtacos.
1. Disconnect the negative (-) cable from the battery,
then the positive {+) cable.
2. Remove the intake 8ir duct and the air cleaner hous-
ing assembly,
AIR CLEANERHOUSINGASSEMBL
Disconnect the back-up light switch connector and
the transmission ground wire.
BACK.UP LIGHTSWITCH CONNECTOR
TRANSMISSIONTRANSMISSIO
GROUND WIRE HANGEB B
4. Remove tne lowei radiator hose"clamp from the
transmission hsnger B.
INTAKE AIR DUCT
13-4
\-
5. Remove the wire hsrness clamps.
VSS CONNECTOR
Disconnect the starter motor cables and the vehicle
speed sensor (VSS) connector.
Remove the clutch pipe bracket and the slave cylin-
der.
NOT€: Do not operate the clutch pedsl once the
slave cvlinder has been removed.
7.
I
T
Remove the three upper transmission mounting
bolts and the lower starter motor mountino bolt.
STARTERMOTOEMOUNTINGBOLT
Drain the transmission oil, then reinstall the drainplug with a new washer (see page 13-3).
Remove the engine splash shield.10.
11.
6tr!
/
SELF.LOC1(ING NUTReplace.
Disconnect the heated oxygen sensor (HO2S) con-
nectors, then remove the exhaust pipe A. and the
three way catalytic converter (B'18C1 and B18C5
engines).
Feplace. THREE WAYCATALYNCCONVERTENlg18C1 lnd 818C5 onginrsl
Remove the cotter pins and loosen the castle nuts,
then separate the ball joints from the lower arm(see sectiotr'l8).
LOWER ARM
DAMPER CASTLE NUTFORK
13. Remove the right damper FORK
(cont'd)
13-5