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
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
3.Fuel Cut-off Control
. Du ring dece leration with the th rottle va lve closed, cu rrent to the fuel injectors is cutoffto improvefuel economyat
speeds over following rpm:. B'1881 engine: 970 rpm {Canada model: 1.050 rpm). B18C1 engine:970 rpm {Canada model: 1.050 rpm). 818C5 engine: 1,300 rpm (Canada model: 1,400 rpm)
. Fuel cut-off action also takes place when engine speed exceeds 7,000 rpm (B'1881 engine), 8.100 rpm (818C1
engine) or 8,600 rpm (818C5 engine), regardless ol the position of the thronle valve, to protect the engine from
over-revving.
A,,/C ComDressor Clutch Relav
When the ECM receives a demand for cooling from the air conditioning system, it delays the compressor from being
energized, and enriches the mixture to assure smooth transition to the A,/C mode.
Evaporative Emission (EVAP) Purge Control Solenoid Valve
When the engine coolanl temperature is above '154'F (68'C) and the air conditioner on. the ECM controls the EVAPpurge control solenoid valve which controls vacuum to the EVAP purge control canister.
Intake Air Eypass (lAB) Control Solenoid Valve*a
When the engine rpm is below 5,750 rpm, rhe IAB control solenoid valve is activated by a signal from the ECM, intake
air flows through the long intake path, then high torque is delivered. At speeds higher than 5,750 rpm, the solenoidvalve is deactivated by the ECM, and intake air flows through the short intake path in order to reduce the resistance in
airflow.
Sell-diagnosis Function lMalfunction Indicator Lamp {MlL)lWhen an abnormality occurs in a signal from a sensor, the ECM supplies ground for the MIL and stores the code in
erasable memory. When the ignition is initially turned on, the ECM supplies ground for the N4lL tor two seconds to
check the MIL bulb condition.
Two Driving Cycle Detection Method
To prevent false indications, the Two Driving Cycle Detection Method is used for the HO2S, fuel metering-related, idle
control system, ECT sensor, TWC and EVAP control system and other self-diagnostic functions, When an abnormality
occurs, the ECM stores it in its memory. When the same abnormality recurs after the ignition switch is turned OFFand ON (ll)again, the ECM informs the driver by lighting the MlL.
However, to ease troubleshooting, this function is cancelled when you shon the service check connector. The MIL will
then blink immediately when an abnormality occurs.
4.
5.
6.
3.
4.
ECM Fail-safe/8ack.up F0nctions
1. Fail-sate Function
When an abnormality occurs in a signal from a sensor, the ECM ignores that signal and assumes a pre-programmed
value for that sensor that allows the enqine to continue to run.
2. Back-uo Function
When an abnormality occurs in the ECM itself, the fuel injectors are controlled by a back-up circuit independent of the
system in order to permit minimal driving.
11-49
The scan tool indicates Diagnostic Trouble Code (DTC) P0122: A low voltage problem in the Throttle Position{TP) sensor circuil.
The TP Sensor is a potentiometer. lt is connected to the throttle valve shaft. As the throttle position changes, the throttleposition sensor varies the voltage signalto the ECM.
ARUSHHOI.DER
BRUSH 5
FULLTHROTTLE
TP SENSOR CONNECTOR IC115)
Wire side of temale terminals
ECM CONNECTOR D {16P)
(GRN/BLUI
Wire side ot female terminals
sG2 / -\
fr rrr r 'tr\
- 1 2 3)
|{- f- /
| _-,/tlI /6 I TPS-\j/
Terminalside of maletermrnats(To page 11-64)
The MIL has be€n reDort€d on.DTC P0122 is stor€d.
Problem veritication:1. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator fan comes on, thenturn the ignition switch OFF.2. Turn the ignition switch ON (ll).
3. Check the throttle positionwith the scan tool.
ls there approx. 10% whenthe throttle is fully closedand approx.90o/o when thethrottle is fully opened?
lntermittenl tailure, system is OKat this time. Check tor poor con-nections or loose wires at Cl15{TP s€nsor) end ECM.
Check lor an open in ihe wire(VCC2line):
1. Turn the ignition switch OFF.2. Disconnect the TP sensor con,nector,3. Turn the ignition switch ON (ll).4. Measure voltage betweenTP sensor connector terminalsNo. l and No. 3.
ls there approx. 5 V7
Check fo. an open in wire IVCC2line):lleasure voltage between ECMconnector terminals D10 and D11.
R.p.ir opon in tho wire betwoenECM {D101 and TP sen3or.ls there approx. 5 V?
Substitute a known-good ECMand recheck. lf pr6sc.ibed volt-age ia now available, replaco theoriginalECM.
Check for an open or 3hort in TP3ensor:1. Turn the ignition switch OFF.2. Measure resistance betweenTP sensor terminals No. '1 andNo.2 with the throttle fullyctoseo,
OUTPUT VOLTAGE {V)
4
RESISTOR3
2
TERMINAL
I
o
THROTTLEOPEI{INGBUS}IINGIDLE
sG2{GRN/BLK)vcc2IYEL/BLU}
vcc2{YEL/BI
l\e
4E
i2iRN,
. llLI5
6/101t 12
t515
(cont'd)
PGM-Fl System
Fuel Supply System
lF0{7il Thescantool indicates Diagnostic Trouble Code (DTC) P0171:Theluel system rstoo lean
[F0i72l Th" ""un tool indicates Diagnosric Trouble code (DTc) p0,172: The fuet system is too rich
Description
By monitoring the Long Term Fuel Trim, long term malfunctions in the luel system will be detected
lf a malfunction has been detected during two consecutive trips, the MIL will come on and DTC P0171 and/or P0172 will be
stored.
NOTE: lf some ol the DTCS lasted below are stored at the same time as DTC PolTl and/or P0172 troubleshoot those DTCS
first, then troubleshoot DTC P0171 andlot P0172
PO107, P0108, P1128. P1129: MAP Sensor
P0135: Primary HO2S Heater (Sensor 1)
P0137, P0138: Secondarv HO2S (Sensor 2)
P0141: Secondary HO2S Heater (Sensor 2)
P1259: VTEC Svstem
Possible Cause
DTC P0171
too lean
Drc P0172
Svstem too rich
. Fuel Pump insufficient flowpressure
. Fuel Feed Line clogged, leaking
. Fuel Pressure Regulator stuck open
. Fuel Filter clogged. Fuel Iniector clogged, air inclusion
. Gasoline doesn't meet Owner's Manual spec.
. Primary HO2S (Sensor 1)deteriorated
. Valve Clearance. Exhaust leak
. Fuel Pressure Regulator clogged, stuck closed
. Fuel Return Pipe clogged
. Fuel Iniector leaking
. Gasoline doesn't meet Owner's Manual spec
' Primary Ho2s (Sensor 1) deteriorated
. Valve Clearance
Troubleshooting Flowchart
HIGH
- The MIL ha3 been rcoortod on.- OTC P0171 andlor PO'l72.re3tored.
ls the Iuel pressure OK?
ls the fuel pressure too highChock th€ luel p.essure regulator,and tu€l return pipe.Ch€ck the Primary HO2S:1. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator lan comes on.2. Check the Primary HO2S{Sensor 1) output with thescan tool.
Chock the tuel pump, fuel feodpipe, fuol fiher, and tuol prcssureregulator.
Does it stay at less than 0.3 Vor more than 0.6 V?Rapl.ce the Primary HO2S {Sen-3or ll.
Check lor a sticking or l€akingEVAP purge control solenoid
With a vacuum pump, apply vacu,um to the EVAP purge controlsolenoid valve.
Does it hold vacuum?
Chock the valvc cl6a.ance3 andadjust it nocessary. lf th. valvocloarance3 are OK, reDlaco thGtuel ini€cto6.
11-77
PGM-FI System
Random Misfire
1T0-500 1 a nd Fo-30ittrrousFF0304-lThB scan tool indicates Diagnostic Trouble Code {DTC) P0300 and some of
P0301 - P0304: Random misfire.
Doscription
Misfir; detection is accomplished by monitoring the crankshaft speed with the crankshaft speed fluciuation sensor which
is attached to the crankshsft.
lf misfiring strong enough to damage the catalyst is detected, the MIL will blink during iho time of its occurrence, and DTC
p0300 and some of DTCS p0301 through P0304 will be stor€d. Then, after misfire has ceased, the MIL will come on.
lf misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTC
PO3O0 and some ot DTCS P0301 through P0304 will be stored
NOTE: lJ some of the DTCS listed below are stored at the same time as a misfire DTC, troubleshoot those DTCS first. then
troubleshoot the misfire DTC.
P0171, P0172: Fuel metering
P0505: ldle Control SYstem
P1361, P1362: TDC sensor
P1381. P1382: CYP sensor
P1508: IAC valve
Possible Cause
. Fuel pump insufficient fuel pressure. amount of flow
. Fuel line clogging, blockage, leakage
. Fuel {ilter clogging
a Fuel pressure regulator stuck open
. Distributormallunction
o lgnition coil wire open, leakage
. lgnition control module malfunction
. Valves carbon deposit
a Compression low
. IAC valve malfunction
. Fast idle thermo valve malfunction
o Fuel does not meet Owner's Manual spec., lackotfu€l
. VTEC system malfunction
Troubleshooting
By test-driving, determine the conditions during which misfire occurs. Depending on these conditions, test in the order
described in the table below.
Fuel
pressure
Distributor
and lgnition
wires
tcMIAC ValveValve
Clearance
wEc
System
11118section 23section 231 1- 100section 6section 6
Only low rpm and
loao@o@@
Only acceleratingo@o
Only high rpm and
loado@@@o
Not specificationo@@@@
NOTE: lf misfire doesn't recur, some possible causes arefuel that doesn't meet owner's manual spec, lackoffuel, carbon
deposits on spark plug, etc.
11-78
Misfire Detected in One Cylinder
I P0301 The scan tool indicates Diagnostic Trouble Code (DTC) PO3O1:Cylinder 1 misfire detected.
[F03021 1;," """n tool indicares Diagnostic Troubte Code (DTC) pO3O2: Cylinder2 misfire detected.
P0303 | ths sssn tool indicates Diagnostic Trouble Code (DTC) PO3O3: Cylinder3 misfire detected.
i P0304 | tne scan tool indicates Diagnostic Trouble code {DTC} PO3O4: Cylinder 4 misfire detected.
Doscription
Misfire detection is accomplished by monitoring the crsnkshaft speed with the crankshaft speed fluctuation sensor whichis attached to the crankshaft.
lf misfiring strong enough to damage the catalyst is detected, the MIL will blink during the time of its occurrence, and DTCP0301, P0302, P0303 or P0304 will be stored. Then, after the m;sfire has ceased, the MIL witt come on.lf misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTCP0301, P0302, P0303 or P0304 will be stored.
NOTE: lf some of the DTCS listed below are stored at the same time as a misfire DTC, troubleshoot those DTCS first, thentroubleshoot the misfi.e DTC.
P0107, P108, P1128,P'1129: MAP sensor
PO171, PO172t Fuel metering
P0505; ldle control system
P1259: WEC System
P1361, P1362: TDC sensor
P138'1, P1382: CYP sensor
P1519: IAC valve
Possibls Caus6
. Fuel injector clogging, fuel leakage, air leakage
. Fuel injector circuit open or shoned. Spark plug carbon deposits, fouling, malfunction. lgnition wires open, leaking
. Distributor malfunction
. Compression low
a Valve clearance out of spec.
(cont'd)
11-79