Troubleshooting
DataDescriotionOperating ValueFreeze Data
HO25
Feedback
Loop Status
Loop status is indicated as "open" or "closed".
Closed: Based on the H02S output, the ECM deter-
mines the airlfuel ratio and controis the amount of
iniected fuel.
Open: lgnoring HO2S output, the ECM refers to sig-
nals from the TP, MAP, and ECT sensors to control
the amount of iniected fuel.
Al idle speed: closed
YES
Short Term
Fuel Trim
The airlfuel ratio correclion coeificient lor correcting
the amount ol iniected fuel when HO2S feedback is in
the closed loop status. When the signal from the
HO2S is weak, short term fuel trim gets highef. and
the ECM increases the amount of injected fuel The
airlfuel ratio gradually gets richer, causing a higher
HO2S output.
Consequentlv, the short term fuel trim is lowered, and
the ECM reduces the amount of injected tuel. This
cycle keeps the airlfuel ratio close to the stoichiomeric
ratio when in closed loop status.
-30o/" - + 41%
YES
Term
Trim
Long
F uel
Long term fuel trim in computed trom short term fuel
trim and indicates changes occurring in the fuel sup-
ply system over a long period.
lf long term fuel trim is higher than 1.00, the amou nt
of injected fuel must be increased. ll it is lower than
1.00, the amount of iniected fuel must be reduced
-14% - + 2Oo/"
YES
lntake Air
Temperature(rAT)
The IAT sensor converts intake air temperature into
voltage and signals the ECM. When intake air temper-
ature is low, the internal resistance of the sensor
increases, and the voltage signal is higher.
With cold engine:
Same as ambient temPer-
ature and ECTYES
Throttle
Position
Based on the accelerator pedal position. the opening
anole of the throttle valve is indicated.
Ar idle: Approx. 107o
At full throttle: Approx.
90%
YES
lgnition
Timing
The ignition advance angle is set by the ECM. The
EClvl matches ignition timing to the driving condi-
tio ns.
At idle speed: 16 t 2'
BTDC with the SCS ser-
vice connector connected.
NO
Calculated
Load Value
(CLV)
CLV is the engine load calculated from the MAP data.At idle speedi
15 - 35%
At 2,500 rpm with no load:
12 - 30./.
YES
-38
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
I
t
h,,l,!
il
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
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
DTC(MlL indication)Dstection ll€mProbable CausePage
P1336 (54)Crankshaft Speed
Fluctuation Sensor
Intermittent lnterruption
. CKF sensor
1190
Pl337 (54)Crankshaft Speed
Fluctualion Sensor
No Signal
CKF sensor
CKF sensor circuit
ECM
'11-90
P't359 (8)
Crankshaft Position/Top
Dead Center/Cylinder Position
Sensor
Connector Disconnection
CKP/TDC/CYP sensor circuit
1't -92
P1361 (8)Top Dead Center
Sensor Intermittent
Interruptaon
. TDC sensor't1-83
P1352 (8)Top Dead Center
Sensor No Signal
TDC sensor
TDC sensor circuit
ECM
1183
P1381 {9}Cylinder Position Sensor
Intermittent Interruption
. CYP sensor11-83
Pl382 (9)Cylinder Position Sensor
No Signal
CYP sensor
CYP sensor circuit
ECM
11-83
P1456*6 (90)
Evaporative Emission Control
System Leak Detected (Fuel
Tank Area)
Fuel fill cap
Vacuum connection
Fueltank
Fuel tank pressure sensor
EVAP bypass solenoid valve
EVAP two way valve
EVAP control canister vent shut valve
EVAP control canister
EVAP purge control solenoid valve
11-146
P14s7*5 {90)
Evaporative Emission Control
System Leak Detected (EVAP
Control Canister Area)
Vacuum connection
EVAP control canister
Fuel tank pressure sensor
EVAP bypass solenoid valve
EVAP two way valve
EVAP control canister vent shut valve
FuelTank
EVAP purge control solenoid valve
'1 'l - 146
P1508 ( 14)
ldle Air Control Valve
Circuit Failure
IAC valve
IAC valve circuit
ECM
1 1-100
P1607 (-)Engine Control
Module Internal
Circuit Failure
. ECM
11-92
(cont'd)
11-45
How to Read Flowcharts
A flowchart is designed to be used from start to final repair. lt's like a map showing you the shone$ distance. But beware:if you go off the "map" anywhere but a "stop" symbol, you can easily get lost.
FTARN(bold type)
FcroNl
@>
sroFl
(bold type)
NOTE:
. The term "lntermittent Failure" is used in these chans. lt simply means a system may have had a failure, but it checksout OK at this time. lf the Malfunction lndicator Lamp (MlL) on the dash does not come on, check for poor connectionsor loose wires at all connectors related to the circuit that you are troubleshooting (see illustration below).. Most of the troubleshooting flowcharts have you reset the Engine Control Module (ECM) and try to duplicate theDiagnostic Trouble Code (DTC). lf the problem is intermittent and you can't duplicate the code, do not continue throughthe flowchart. To do so will only result in confusion and, possibly, a needlessly replaced ECM.. "Open" and "Short" are common electrical terms. An open is a break in a wire or at a connection. A short is an acci-dental connection of a wire to ground or to another wire. In simple electronics, this usually means something won,twork at all. In complex electronics (like ECM's), this can sometimes mean something works, but not the way rr s sup-posed 10.
Describes the conditions or situation to start a troubleshootinq flowchart
Asks you to do something; perform a test, set up a condition etc.
Asks you about the result of an action, then sends you in the appropriate troubleshooting direction.
The end of a series of actions and decisions, describes a final repair action and sometimes direcls you toan earlier part of the flowchart to confirm your repair.
11-47
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