DATA LINK CONNECTOR {DLC) I16P}Troubleshooting Procedures, page 1 1'60PRIMARY HEATED OXYGEN SENSOR
{PRIMARY HO2SI {SENSOR 1)Troubleshooling, page 11 110
SECONDARY HEATED OXYGENSENSOR{SECONDARY HO2S) {SENSOR 2)Troubleshooting, page 1 1-1 17
'97 - 98 models:
AIR CLEANERReplacement, page 1 1'194
Troubleshooting, page 1 'l -200
THROTTLE BODY (TB)Inspection, page 11 196Removal, page 11-197Disassembly, page 1 1-'198
POWERTRAIN CONTROL MODULE(PCM) (A/TI
Troubleshooting Procedures, page 1 1-60Troubleshooting. page 1 1'82
THROTTLE CABLEInspection/Adjustment, page 1 1-1 94Installation, page 11- 195
VENTILATION (PCV) VALVEInspection, page 1 1-201FAST IDLEVALVE (A/T}
(cont'd)
1 1-5
PGM-FIMAIN RELAYRelay Testing, page 11-l87Troubleshooting. page 1'1 188
SERVICE CHECK CONNECTOR {2PITroubleshooting Procedures, page 1 1-60
,a'=_-_
WAY CATALYTIC
Inspection, page 1 1-168
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Troubleshooting
Troubleshooting Procedures
How To Begin Troubleshooting
When the Malfunction indicator Lamp (MlLl has been reported on, or there is a driveability problem, use the appropri-ate procedure below to diagnose and repair the problem.
A. When the MIL has come on:
1. Connect the Honda PGM Tester or an OBD Il scan tool to the 16P Data Link Connector (DLC) located behind theright side of the center console.
Turn the ignition switch ON (ll).
Check the DTC and note it. Also check and note
the freeze frame data.
Refer to the Diagnostic Trouble Code Chart and
begin troubleshooting.
NOTE:
. SeetheOBDll scan tool or Honda PGM Tester user's manuals for specific operating instructions.. The scan tool or tester can read the Diagnostic Trouble Codes (DTC), freeze frame data, current data, and otherEngine Control Module (ECM}/Powertrain Control Module (PCM) data.. Freeze frame data indicates the engine conditions when the first malfunction, misfire or fuel trim malfunction wasdetected. lt can be useful information when troubleshootino.
B. When the MIL has not come on, but there is a driveability problem, refer to the Symptom Chart on page 11-64.
C. DTCs will be indicated by the blinking of the Malfunction Indicator Lamp {MlL) with the SCS service connector con-nected.
Connect the SCS service connector to Service Check Connector as shown. {The 2P Service Check Connecror rslocated behind the right side of the center console.) Turn the ignition switch ON 0l).
DATA LINK CONNECTOR I16PI
1 1-60
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ll. Engine Controt Module (EcM)/Powertrain Control Module {PCM) Reset Procedure
Either of the following actions will reset the ECM/PCM.
. use the oBD ll scan tool or Honda PGM Tester to clear the ECM' s/PCM' s memory. (see the oBD ll scan tool or
Honda PGM Tester user's manuals for specific operating instructions )
. Turn the ignition switch oFF. Remove the BACK UP (RADIO) (7.5 A) fuse from the under-hood fuse/relay box for 10
seconos.
lll. Final Procedure {this procedure must be done after any troubleshooting)
1. Remove the SCS Service Connector if it is connected. lf the SCS service connector is connected. and there are no
DTCS stored in the ECM/PCM, the MIL will stay on when the ignition switch is turnsd oN (ll).
2. Do the ECM/PCM Reset Procedure.
3. Turn the ignition switch OFF
4. Disconnect the OBD ll scan tool orHonda PGM Tester from the Data Link Connector ( 16P)'
(cont'd)
1 1-61
BACK UP {RADIOI I7,5 AI FUSE
FUSE/RELAY BOX
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ECM/PCM Data
By connecting the OBD ll scan tool or the Honda PGM Tester to the 16P data link connector (OLC), various data can be
retrieved from the ECM/PCM. The items listed in the table below conform to the SAE recommended practice
The Honda PGM Tester also reads data beyond that recommended by SAE.
understanding this data will help to find the causes of intermittent failures or engine problems.
NOTE:
The ',operating values" given below are approximate values and may be different depending on the environment and
the individual vehicle.
Unless noted otherwise. "at idle speed" means idling with the engine completely warmed up, transmission in position
Park or neutral and the A,./C and all accessories turned otf.
DataDesc.iptionOp€rating ValuoFreeze Data
Diagnostic
Trouble Code
(DTC)
lf the ECM/PCM detects a problem, it will store it as a
code consisting of one letter and tour numbers
Depending on the problem, an SAE-defined code (Poxxx)
or a Honda-defined code (P'lxxx) will be output to the
tester.
lf no problem is detected,
there is no output.
YES
Engine SpeedThe ECN4/PCN4 computes engine speed from the signals
sent from the Crankshaft Position sensor.
This data is used for determining the time and amount of
fuel iniection.
Nearly the same as
tachometer indication
At idle speed:'97 - 98 models:
750 t 50 rpm'99 - 00 models:
730 f 50 rpm
YES
Vehicle SpeedThe ECM/PCM converts pulse signals from the Vehicle
Speed Sensor (VSSI into speed data.
Nearly the same as
speedometer indicationYES
Manifold
Absolute
Pressure (MAP)
The absolute pressure caused in the intake manifold by
engine load and speed.
With engin6 stopped:
Nearly the same as atmo-
spheric pressure
At idle speed:
2a - 41 kPa {210 - 310
mmHg, 8.3 - 12.2 inHg)
YES
Engine Coolant
Temperature
{ECT)
The ECT sensor converts coolant temperature into volt-
age and signals the ECM/PCM. The sensor is a thermistor
whose internal resistance changes with coolant tempera-
ture. The ECM/PCM uses the voltage signals from the
ECT sensor to determine the amount of injected fuel
With cold engine:
Same as ambient temPer-
ature and IAT
With engine warmed uP:
approx. 163 - 2'12'F
(73 - 100"c)
YES
Heated Oxygen
Sensor (HO25)
(Primary,
Sensor 1)
(Secondary
Sensor 2)
The Heated Oxygen Sensor detects the oxygen content in
the exhaust gas and sends voltage signals to the
ECMiPCM. Based on these signals, the ECM/PCM controls
the airlfuel ratio. When the oxygen content is high (that is.
when the ratio is leaner than the stoichiometric ratio), the
voltage signal is lower.
When the orygen content is low (that is, when the ratio
is richer than the stoichiometric ratio), the voltage signal
is higher.
0.0 - 1.25 V
At idle speed:
about 0.1 - 0.9
NO
(cont'd)
1 1-65
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Troubleshooting
Troubleshooting Procedures (cont'd)
DataDescliptionOperating ValueFreezo Data
HO2S
Feedback
Loop Status
Loop status is indicated as "open" or "closed".
Closed: Based on the HO2S output, the ECM/pCM deter-mines the airlfuel ratio and controls the amount ofinjected fuel.
Open: ignoring HO2S output, the ECM/pCiM refers to sig,nals from the TP, MAP, and ECT sensors to control theamount of injected fuel.
At idle speed: closed
YES
Short Term
Fuel Trim
The airlfuel ratio correction coefficient for correcting theamount of injected fuel when HO2S feedback is in theclosed loop status. When the signal from the HO2S isweak, short term fuel trim gets higher, and the ECM/PCMincreases the amount of injected fuel. The airlfuel ratiogradually gets richer, causing a higher HO2S output.Consequently. the short term fuel trim is lowered. andthe ECM/PCM reduces the amount of injected fuel.This cycle keeps the airfuel ratio close to the stoichio-metric ratio when in closed looD status.
t:20y"
YES
Long Term
Fuel Trim
Long term fuel trim is computed from shon term fueltrim and indicates changes occuring in the fuel supplysystem over a long period.
lf long term fuel trim is higher than 1,00. the amount ofinjected fuel must be increased. lf it is lower than L00.the amount of injected fuel must be reduced.
! 20%
Intake Air
Temperature
(IAT)
The IAT sensor converts intake air temperature into volt-age and signals the ECrU/PCM. When intake air tempera-ture is low, the internal resistance of the sensorincreases, 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 openingangle of the throttle valve is indicateo.At idle speed:
approx. 10%
lgnition
Timing
lgnition timing is the ignition advance angle set by theECM/PCM. The ECM/PCM matches ignition timing to thedriving conditions.
At idle speed: 16'1 4.
BTDC with the SCS ser-
vtce connector connected.
NO
Calculated
Load Value(cLV)
CLV is the engine load calculated from the MAp data.At idle speed:
2A - 410/o
At 2,500 rpm with no load:
13 - 260/o
YES
_
1 1_66
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NOTE:. When there is no Diagnostic Trouble Code (DTC) stored, the MIL will stay on if the SCSservice connector is connected and the ignition switch is on.. lf this svmotom is intermittent, check for:- A loose Fl E/M (15 Aifuse in the underdash tuse/relay box- A loose No. 13 FUEL PUMP {15 A) fuse in the under-dash fuse/relay box- An intermittent short in the wire between the PCM (C7) and the service check con-
- An intermittent short in the wire between the PCM (A18) and the gauge assembly- An intermittent shon in the wire betlveen the PCM (D4) and the MAP sensor- An intermiftent short in the wire between the PCM {D10) and the TP sensor.PGM-Fl main relay.'See the OBD ll scan tool or Honda PGM Tester user's manuals lor specilic operatinginstructions,
NOTE: An open or short in the wire between the PCM (C8) and the DLC will keep thescan tool or Honda PGM Tester lrom communicating with the PCM. You should ioterpretthis as no DTCS are indicated.
PCM CONNECTORc l3lPl scs .BRNI
lTo page 11 84)Wire sid6 of f€male terminalg
(cont'dl
11-83
The Malfunciion lndicator Lamo{MlL) stavs on o. comes on afteltwo seconds,
Check the Oiegnosiic TroubleCode (DTC):
1. Connect an OBD ll scan toolor Honda PGM Tester.2. Turn the ignition switch ON 1lli.3. Read the DTC with the scantool or Honda PGII Tester.
Go to troubleshooting procedures(s€€ page 11501.Are any DTCIs) indicated?
Ch6ck lh6 DTC by MIL indication:1. Turn the ignition switch OFF.2. Connect the SCS service con-nector to the service checkconnector.3. Turn the ignition switch ON (ll).
- Repair opon or short in wi.6between the PCM (C8) andData Link Connector.- Go to troubloshooting proce-
dur€s {3ee page 11-601.
Does the MIL indicate any DTc?
Try to start the engine.
Does the engine start?
Check tor a short in the wire{SCS line):1. Turn the ignition switch OFFand turn the ignition switchoN flt).2. Measure voltage between thePCM connector terminal C7and body ground.
Repair short to body ground inthe wire between PCM lCTl andservice check connector.ls there approx. 5 V?
(To page 1'l-84)
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PGM-FI System
Misfire Detested in One Cylinder (cont'dl
Troubl93hooting Flowchart
The illu stration shows'97 - 98 models,'99 - 00 modelsare similar.
NOTE:.lf there is no freeze data ol misfiring,just clear the DTC..lf there is no freeze data ot misfiring,test drives under various conditionsare necessary,
- Th. MIL h!3 b6on r.portod on.- DTC m30r, P0302, m303. orP0304 is indicated.
Ch.ck tho fuol inicctor tunction:Start the engino, and listen for Iclicking sound at the fuol injectorin the probl€m cylinder.
Check for an open or short in theharness between the ECM/PCMand the luel injector.
Boprir opan or 3hort in tha wlre.
- Roplaco th. tuel inioctor.- Substitut. . known-goodECM/PCM .nd rochock. It3ym ptom/ indicati on go.3aw.y, replace the oliginalECM/PCM.
Problom vorification:1. Atter chacking the lre€ze data,do the ECM/PCM Reset Pro-cedure.2. Exchange the spark plug fromthe problem cylinder with oneol another cylinder.3. Connect the SCS service con-nector.4. Tost-drive the vohicle severaltimes in the rango ol the freezedata.
(To page'11-129)
11-128
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(From page 11-128)
lntormittent misfire due lo sparkplug fouling, etc. (no mislire at
this tim€).
ls DTC P0301, P0302, P0303,or P0304 indicated?
ooes the misfire occur in theother cylinder?Replace the faulty spark Plug.
Check lor fuel iniector maltunc-
t|on:1. Exchange the fuel injectorfrom the problem cylinderwith one from another cylin-der.2. Let the engine idle for two min
utes.3. Test'drive the vehicle severaltimes in the range of the freezedata,
lntermittent misfiro due lo bad
contrct in the fuel iniector con-nector {no misfire at this time).
ls DTC P0301, P0302, P0303,or P0304 indicated?
Does the misfire occur in theother cylinder?Replace lhe faulty luel inlector.
Check following items- Valvo clearance- Cvlinder l€ak-down- Compression- Crsnkshaft Speed FluctuationICKF) sensol
NOTE: lf there is no freeze data of misfiring, test drives under various condi_
tions are necessary.
11-129
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