ECM Data
By connecting the OBD ll scan tool or the Honda PGM Tester to the 16P data link connector (DLC), various data can beretrieved from the EcM The items risted in the tabre berow conform to the sAE recommended practice.The Honda PGM Tester also reads data beyond that recommended bv SAE.understanding this data wirl herp to rind the causes of intermiftent fairures or engine probrems.
NOTE:
' The "operatlng values" given below are approximate values and may be different depending on the environment andthe individual car.' Unless noted otherwise, "at idle speed" means idling with the engiFe completely warmed up, transmissron in park orneutral and the A,/C and all accessories turned off.
DataDescriptionOperating ValueFreeze Data
Diagnostic
Trouble Code(DTC)
lf the ECM detects a problem, it will store tt as a cocteconsisting ot one letter and four numbers.Depending on the problem, an SAE-defined code{Poxxx) or a Honda-defined code (plxxx) will beoutput to the lester.
lf no problem is detected,
there is no output.
YES
Engine SpeedThe ECM computes engine speed from the signalssent from the Crankshaft Position sensor.This data is used for determining the I|me andamount of fuel injection.
Nearly the same as
tachometer indication at
idle speed:
81881,818C1 engines:
750 t 50 rpm
818C5 engine:
800 1 50 rpm
YES
Vehicle SpeedThe ECM converts pulse signals trom the VehicleSpeed Sensor (VSS) into speed data.
Nearly the same as
speedometer indicationYES
Manitold
Absolute
Pressure {MAP)
The absolute pressure created in the intake manifoldby engine load and speed.With engine stopped:
Nearly the same as atmo
spheric pressure. At idle
speed:
24 - 37 kPa (180 - 280
mmHg,7.1 1'1.0 inHg)
YES
Engine Coolant
Temperature
(ECT)
The ECT sensor converts coolant temperature intovoltage and signals the ECM. The sensor is a thermis-tor whose internal resistance changes with coolanttemperature. The ECM uses the voltage signals fromlhe ECT sensor to determine the amount of iniectedfuel.
With cold engine:
Same as ambient temper
ature and IAT
With engine warmed up:
approx. 176 - 200'F
{80 - 93.C)
, YES
Heated Oxygen
Sensor (HO2S)
{sensor 1)(sensor 2)
The Heated Oxygen Sensor detects the oxygen con-tent in the exhaust gas and sends voltage signals tothe ECM. Based on these signals,lhe ECM controlsthe airlfuel ratio. When the oxygen content is high{that is, when the ratio is leaner than the stoichiomericratio), the voltage signal is lower. When the oxygencontent is low (that is, when the ratio is richer thanthe stoichiomeric ratio), the voltage signal is higher.
0.0 - 1.25 V
At idle speed:
abour 0.'1 - 0.9 V(sensor I )NO(sensor 1)
(conl'd)
11-37
Engine Control Module Terminal Arrangement
ECM CONNECTOR A I32P}
ECM CONNECTOR A I32PI
*1: USA*2:818C1 engine*3:A,/T*4: 818C1, 818C5 engines
female terminals
NOTEr Standard battery voltageis 12 V.
{cont'di
LG22A
TerminalWireTerminal nameDescriptionSignal
YELlNJ4 (No. 4 FUEL INJECTOR)Drives No. 4 fuel iniector.With engine running: pulses2BLUlNJ3 (No.3 FUEL INJECTOR)Drives No. 3 fuel injector.
3REDlNJ2 (No.2 FUEL INJECTOB)Drives No.2 fuel injector.
BRNlNJl (No. 1 FUEL INJECTOR)Drives No. l Iuel iniector.
5GRN/REDS 02SHTC (SECONDARY
HEATED OXYGEN SENSORHEATER CONTROL)
Drives secondary heated oxygensensor heater,With ignition switch ON (ll)i battery volrageWith fully warmed up engine runningiduty controlled
6ORN/BLKP O2SHTC {PRIMARY HEAIEDOXYGEN SENSOB HEAIERCONTFOL)
Draves primary heated oxygensensor heater,With ignition swirch ON (ll): battery voltageWith lully warmed up engine running:duty controlled
84G RNI/ELVTS (VTEC
SOLENOID VALVE)Drives VTEC solenoid valve.With engine at low rpm: 0 VWith engine at high rpm: battery voltageIBRN/BLKLG1 (LOGIC GROUND)Ground for the ECM control circuit.Less than 1.0 V at alltimes10BLKPGl (POWER GROUND)Ground for the EC[, power circuit.Less than 1.0 V at all times't'lYEUBLKIGPl {POWER SOURCE)Power source for the ECMcontrolcircuit.With ignition switch ON 1ll): battery voltageWith ignition switch OFF| 0 V
12BLI(8LUIACV(IDLE AIR CONTROL VALVE}Drives IACV.With engine running: about 6 V 10 V(depending on engine speed)
REDPCS (EVAP PURGE CONTROLSOLENOID VALVE)Drives EVAP purge controlsolenoid valve.Wilh engane running, engine coolant above154"F (68'C): duty controlled
GRN/BLUFLR (FUEL PUMP RELAY)Drives fuel pump relay.0 V for two seconds after turning ignitionswitch ON (ll), then battery voltage
17B LVBEDACC (fuC CLUTCH RELAY)Drives A,/C clulch relay.With compressor ON: 0 VWith compressor OFFt baftery voltage
18GRN/ORNMIL (I\4ALFUNCTION
INDICATOR LAMPiDrives MlL.With MIL turned ON:0 VWjth MIL turned OFF: battery vottage
19*,WHT/GRNALTC (ALTERNATOR
CONTROL)Sends alternator control signal,With fully warmed up engine runninglbattery voltageDuring driving with small electrical load: 0 V
20YEUGRNICM (IGNITION CONTROLMODULE)Sends ignition pulse.With ignition switch ON (ll): battery voltageWith engine running: about'10 V(depending on engine speed)22BRN/BLKLG2 (LOGIC GROUND)Ground forthe ECM controlcifcuit.Less than 1.0 V at all times8LKPG2 (POWEfl GROUND)Ground for the ECM power circuit.Less than 1.0 V at all times
24YEUELKIGP2 (POWER SOURCE)Power source for the ECMcontrolcircuit,With ignition switch ON {lli: battery voltageWith ignition switch OFF: 0 V
25*3WHT/BLKVREF (REFERENCE VOLTAGE)Provides reference voltage toother control units,With ignition swirch ON (ll): about 5 VWath ignition switch OFF: 0 V
26. 'PNK/8LU
IAB SOL (INTAKE AIR BYPASSCONTROL SOLENOID VALVE)Drives IAB conlrol solenoidWith engrne running, engrae speed betow5,750 rpm: battery voltageWith engine running, engine speed above5,750 rpm: 0 V
27* IGRNFANC (BADIATOR FANCONTROL)Drives radiator fan relay.With radiator {an running: 0 VWith radiator Ian stopped: battery voltage
2ABLU2WBS (EVAP BYPASSSOLENOID VALVE)Drives EVAP bypass solenoidWith ignition switch ON (ll): battery vottage
29LT GRNVSV (EVAP CONlROLCANISTER VENT SHUT VAVLE)Drives EVAP control canister ventshut valve.Wilh ignilion switch ON lll): banery votrasc
1 1-39
ECM CONNECTOR D (16P}
Wire side of female terminals
ECM CONNECTOR D (16P1NOTE| Standard battery voltage is 12 V.
TerminalnumberWirecolorT6rminal nameDoscriptionSignal
1RED/BLKTPS (THROTTLE POSITIONSENSOR)Detects TP sensor s;gnal.With throttle fully open: about 4.5 VWith throttle fully closed: about 0.5 V
2REDAr'r'HTECT (ENGINE COOLANTTEMPERATUBE SENSOB}Detects ECT sensor signal.With ignition switch ON (ll)r about0.1 - 4.8 V (depending on engine coolanttemperalure)
3WHT//ELMAP {MANIFOLD AESOLUTEPBESSURE SENSOR)Detects MAP sensor signal.With ignition switch ON (ll)iabout 3 VAt idle: about 1.0 V {depending on enginespeeol
4YELA/VHTvccl{SENSOR VOLTAGE)Power source for MAP sensor,With ignition switch ON (ll): about 5 V
5GRNAVHTBKSW (BRAKE SWITCH)Detects brake switch signal.With brake pedal released: 0 VWith brake pedal depressed: batteryvoltage
6*!RED/BLUKS (KNOCK SENSOR}Detects KS signal.With engine running: pulses
lPHO2S (PRIMARY HEATEDOXYGEN GENSOR)Detects primary oxygen sensorsignal.With throttle fully opened, fully warmed upengine: above 0.6 VWith throttle quickly closed: below 0.4 V
8RED/VEL
IAT (INTAKE AIRTEMPERATURE SENSOR)Detects IAT sensor signal.With ignition switch ON {ll): about0.1 - 4.8 V (depending on intake airtemperature)
10YEL/BLUvcc2(SENSOB VOLTAGE)Provides sensor voltage,With ignition switch ON (ll): about 5 VWith ignition switch OFF: 0 V
1lGRN/8LUSG2 (SENSOR GROUND}Sensor ground.Less than 1.0 V at all times.
GFNA/VHT(SENSOR GROUND}Ground tor MAP sensor.Less than 1.0 V at all times.
OBN/BLUSHO2S GND (SECONDARY
HEATED OXYGEN SENSORGROUND)
Ground for secondary heatedoxygen sensor,Less than 1.0 V at alltimes.
148LU/REDSH02S (SECONDARY
HEATED OXYGEN SENSOR}Detects secondary oxygensensor srgnal.With throttle fully opened. fully warmed upengine: above 0,6 VWith throttle quickly closed: below 0.4 V
LT GRNPTANK (FUEL TANK PRESSURE SENSOR)Detects fueltank pressure sensor.With luel fill cap opened: about 2-5 V
GRN/RED
EL (ELOiDetects ELD signal.With parking lights turned on at idle: about2.5 -3.5 VWith low beam headlights turned on at idle:about 1.5 - 2.5 V*1:USA*2: 818C1 engine"3:A"/T*4: B18C'1, 818C5 engines
11-41
1l
Troubleshooting
Diagnostic Trouble Gode (DTCI Chart
*: These DTCS will be indicated by the blinking ot the lvalfunction Indicator Lamp (MlL) with the SCS service connector
connected.
Ia
\
\
il
\
DTC
lMlL indication*lDetection ltemProbabls CausePage
P0107 (3)
Manifold Absolute
Pressure Circuit
Low Input
Open or short in MAP sensor circuit
MAP sensor
ECM
'11-54
P0108 (31
Manifold Absolute
Pressure Circuit
High Input
Open in MAP sensor circuit
MAP sensor
ECM
tt-5t,
P0112 (10)
Intake Air
Temperature Circuit
Low Input
Short in IAT sensor circuit
IAT sensor
ECM
11.58
P0113 {10)
lntake Air
Temperature Circuit
High Input
Open in IAT sensor circuit
IAT sensor
ECM
1' 1-59
P0116 (86)
Engine Coolant
Temperature Circuit
Range/Performance Problem
. ECT sensor' Cooling system11-60
P0117 (6)
Engine Coolant
Temperature Circuit
Low Input
Short in ECT sensor circuit
ECT sensor
ECM
1 ' t-61
P0118 {6)
Engine Coolant
Temperature Circuit
High Input
Open in ECT sensor circuit
ECT sensor
ECt\,4
1't -62
P0122l7l
Throttle Position
Circuit
Low Input
Open or shon in TP sensor circuit
TP sensor
ECM
11,63
P0123 (7)
Throttle Position
Circuit
High Input
Open in TP sensor circuit
TP sensor
ECM
I t-oc
P0131 (1 )
Primary Heated Oxygen Sensor
Circuit Low Voltage (Sensor 1)
Shon in Primary HO2S (Sensor'l) circuit
Primary H02S {Sensor 1)
Fuel supply system
ECM
11-67
P0132 (1)Primary Heated Oxygen Sensor
Circuit High Voitage (Sensor 1)
Open in Primary HO2S (Sensor 1) circuit
Primary HO2S (Sensor 1)
ECM
11-69
P0133 (61)Primary Heated Oxygen Sensor
Slow Response (Sensor 1)
. Primary HO2S (Sensor 1). Exhaust system1 1-70
,r:' 11-42
L
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
PGM-FI System
Engine Coolant Temperature (ECTI Sensor
Ip01161 Ihe,scaltool indicates Diagnostic Trouble Code (DTC) P0116: A range/performance problem in the Engine: Coolant Temperature {ECT) Sensor circuit.
The ECT Sensor is a temperature dependant resistor (thermistor). The resistance of the thermistor decreases as the engine
coolant temperature increases as shown below.
RESISTANCEtkol
! 32 68 104 140 i 76 212 248 { "F)-20 o 20 'ra, qt Il rd' t20 r'c)
ENGINE COOLANT TEMP€RATURE
P01 16, troubleshoot those DTCS first, then trou-NOTE: lf DTC P0117 andlo( Po'l'18 are stored at the same time as DTC
bleshoot DTC P0'l16.
Possible Cause
. ECT sensor deterioration
. Malfunction in the thermostat and the cooling system
lroubleshooting Flowchart
I
1 1-60
THERMISTOR
- Th€ MIL has been reoorted on.- DTC P0116 is stored.
Problem veritication:1. Start lhe engine. Hold theengine at 3,000 rpm with noload (in Park or neutrall untilthe radiatorlan comes on, thenlet it idle.2. With the scan tool, check theECT,
Inlermittent failure, system is OKat this time. Chock tho thermostaland th€ cooling syst6m.
ls 176 - 200"F (80 - 93'C) or0.4-0.TVindicated?
Check the thermostat and thecooling system. It th€y ara OK,reolace the ECT sensor,
The MIL has b€en reoorted on.DTC P0117 is stored.
Problem verification:1. Turn the ignition switch ON (ll).2. Check the ECT with the scantool.
Intermittent failure, system is OKat this time. Check for poor con-nections or looso wires at C111(ECT sensorl and ECM.
ls 302'F (150'C) or higher {orH Limit in Honda mode ofPGM Tester) or 0 V indicated?
Check tor a short in tho ECT sen-sor:1. Disconnect the ECT sensor
2. Check the ECT with the scantool.
ls 302'F (150'Ci or higher (orH-Limit in Honda mode olPGM Tester) or 0 V indicated?
Check tor s short in the wires (ECTline):r. r urn Ine rgnrtron swttch uFf,2. Disconnect the ECM connector D (16P).
3. Check lor continuity betweenECT sensor connector termi,nal No. 1 and body ground.
Check tor short in the TCM IECTlinell1, Disconnect the 22P connectorfrom the TCM.2. Check for continuity betweenECT sensor connector terminal No- 2 and body ground.
ls there continuity?
Repair shon in the wire botweenECM lD2). TCM and ECT sensor.
iT,011tl The.scan tool indicates Diagnostic Trouble Code (DTC) P0117:Alowvoltage(hightemperature) probleminthe- Engine Coolant Temperature (ECT) sensor circuit.
ECT SENSOR CONNECTOR IC111}
Wire side of fem6le terminals
Substitute a known-good ECMand recheck. lI normal ECT isindicated, replaco the origindlECM.
(cont'd)
NO
11-61
\
r
I
Ir
PGM.FI
Engine
System
Coolant Temperature (ECTI Sensor (cont'dl
lTo1ig I The.scan tool indicates Diagnostic Trouble Code (DTC) P01 18: A high voltage (low temperature) problem in the.- Engine Coolant Temperature (ECT) sensorcircuit.
ECT SENSOR CONNECTOR (C111)
L
li
li
tllll
tl
fl
ECT{RED/WHT)
sG2{GRN/BLKI
JUMPER WIRE
Wire side o{ lemale terminals
ECM CONNECTOR D {16PI
ECT{RED/WHT)
The MIL has been repo.ted on.DTC P0118 is stor€d.
Problem v€riticetion:1. Turn the ignition switch ON (ll).
2. Check the ECT with the scantool.
Intermittont failure, svstom i3 OKat this time. Check for poor con-noctions or looso wires at C111{ECT sensorl and ECM.
ls -4'F (-20"C) or less (or L-Limitin Honda mode of PGM Tester) or5 V indicated?
Chock tor an opon in the ECT s6n-sor:t. utsconnect tne EL I sensor
2. Install a jumper wire betweenthe two terminals on the harness side of the ECT sensor
3. Check the ECT with the scantool,
ls -4'F (-20"C) or less (or L-Limitin Honda mode of PGM Tested or5 V indicated?
Ch6ck Ior an open in the wiresIECT, SG2lines):1. Turn the ignition switch OFF.2. Install a jumper wire betweenECM conneclor terminals D2and D11.3. Turn the ignition switch ON (ll).4. Check the ECT with the scantool.
ls -4'F {-20'C) or less (or L-Limitin Honda mode ol PGM Tester) or5 V indicated?
Ropair op6n in the wires betwo€nECM lD2, D11) and ECT 3eBor.
Substitute a known-good ECMand recheck. lf normal ECT isindicated, replace the originalECM.
JUMPER WIRE
sG2
r-zlr r5
5e I/ 101t't2
l5
Wire side of female terminals
L