Troubleshooting
Diagnostic Trouble Code (DTCI Ghart (cont'd)
DTClMlL indicationlDetegtion homProbablo CsussPage
P1491*! \12J
EGR ValveLift InsufficientDetected
EGR valve (with lift sensor)EGR valve lift sensor circuitEGR control solenoid valve (A,/I)
EGR control solenoid valve circuitEGR lineEGR valve circuit (M/T)
ECM
't1-256
P1498*. 112)
EGR ValveLift SensorHigh Voltage
EGR valve (with lift sensor)EGR valve lift sensor circuitECM11-265
Pl508*10 (14)
ldle Air Control ValveCircuit FailureIAC valveIAC valve circuitECM
'11-194
{14)
ldle Air Control ValveCircuit FailureOpen or short in IAC valve circuitIAC valveECM/PCM1l-198
P1607 1-)
Engine ControlModule/Powertrain Control lvlodulelnternalCircuit Failure A
. ECM/PCM
11-188
P1655*1 (30)TMA,/TMB Signal Line FailureODen or sho.t in TMA,/TMB circuit11-189
P1705P1706P 1753P1758P1768P1785P1790P1791P1793 (70)*
P1870P1873P1879P1885P1886P1888P1890P1891
Automatic Transaxle
Section 14
*: The E indicator light and the Malfunction Indicator Lamp {MlL) may come on simultaneously.*4: D16Y5 engine (M/T)+10: Except A/T and Dl6Y7 engine*11: A,/T and D16Y7 engine*18: D16Y5 engine (CW) (except '99 - 00 models)
11-102
PGM-FI System
Random Misfire
lFoioo l*u o, [FTioo l*' *' and
The scan tool indicates Diagnostic Trouble Code (DTC)
P0300*5 or P1300*3 *1 and some of P0301 - P0304:Random misfire.Description
Misfire detection is accomplished by monitoring the crankshaft speed with the crankshaft speed fluctuation (CKF) sensorwhich is 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 DTCP0300*5 or P1300*3'*' and some of DTCs P0301 through P0304 will be stored. Then, after misfire has ceased, the MIL willcome on.
lf misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTCP0300*5 or P1300*3 *a and some of DTCS P0301 through 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, thenrecheck for the misfire DTC.
P0106*4. P0107. P0108, P1128*3 *5, Pl129*3 *5; MAP sensorP0131. P0132: HO2S
P0171, P0112i Fuel metering
P0401, P 1491, P1498: EGR svstem*1P0505: ldle Control SystemP1253: VTEC System*,P1361, P1362: TDC sensorP1381, Pl382: CYP sensorP1508: IAC valve
Possible Cause. Fuel pump insufficient fuel pressure, amount of flow. Fuel line clogging, blockage, leakage. Fuel filter clogging. Fuel pressure regulator stuck open. EGR system malfunction*1. Distributormalfunction. lgnition coil wire open. leakage *l: D16Y5 engine. lgnition control module malfunction *2: D16Y5, D16Y8, Bt6A2 engine. MAP sensor range/performance, poor response*r *3: '97 models. Valves carbon deposit *4;'96 models. Compression low *5: '98 - 00 models. IAC valve malfunctionr.. VTEC system malfunction*,. Fuel does not meet Owner's Manual spec., lackoffuel. HO2S. HO2S circuit
Troubleshooting
By test-driving, determine the conditions during which misfire occurs, Depending on these conditions, test in the orderdescribed in the table below.
Possible
- --^ ---
rage
causeEGR*1
system
Crankshaft
position (CKP)
sensor
Fuel
pressure
Distributor and
lgnition wirestcMClearance
tAc
ValveMAP
sensor
section 611-230,
231section 23section 23section 611-19411
Only low rpm and
loado@@oo
Only accelerating@o@@
Only high rpm and
toaooo@
Not specificoo@
NOTE: lf misfire doesn't recur, some possible causes are fuel that doesn't meet owne/s manualspec, lack of fuel, carbon deposits on spark plug, etc.
1 1-1 66
I
P0304
ldle Control System
ldle Air Control (lACl Vatve ('96 - 98 Dl6ys, Dl6yB engine with M/Tl
The scan tool indicates Diagnostic Trouble Code (DTC) P1508: A problem 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 inorder to maintain the proper idle speed.
IAC VALVE 2P CONNECTOR ICl3A)
,flrcerh-:J iYEL/BLKI
!.__-,/ -lt(v)
-T-=
Wire side of female terminals
tAcv(BLK/
ELUI
ECM CONNECTOR A I32PI
Wire side oI lemal€ terminals
VALVE
6a10ll12t3r5t6l7t8t920232a
t*25&a2A3o
The MIL hss b€on repo.ted on.DTC P'l508 i. itorod.
Problem vorification:1. Do the ECM/PCM Reset Pro-cedure,Start the engine, and warm ituP to normal operating tem-perature.
Intormittont t!llur., sy.tcm b OKat thb tim6. Chsck fol poor con-ncctionr or loo3e wirot at C138(lAC valv.l.nd ECM.
ls DTC P1508 indicated?
Check for an opcn in the wiro(lGPl line):1. Turn the ignition switch OFF.2. Disconnect the IAC valve 2Pconnector.3. Turn the ignition switch ON (ll).
4. Measure vohage between bodyground and the IAC valve 2Pconnectorterminal No. 2.
R.prir opan in the wiro botwa.nIAC valv..nd PGM-FI main r.l.y.
Chock for an opon or sho in thewire (IACV linal:1. Turn the ignition switch OFFand reconnect the IAC valveconnector.2. Disconnect the ECM connectorA (32P).
3. Turn the ignit;on switch ON (ll).4. Measure voltage betweenbody ground and ECM con-nector terminal A12.
(To page 1l-195)
11-194
I
I
(From page 11-194)
Repair open or short in the wirebetween ECM lAl2l and IAC
Check the IAC valve Iunction:Momentarily connect ECM con-
nector terminals A12 and A10
with a jumPer wire several times.
Does the IAC valve click?
Substitute a known-good ECM
and recheck. It symPtom/indica-tion goes away, replace the origi-
nal ECM.
Wire side of female terminals
