1998 HONDA CR-V Ac system

Fuel Cut-off Control
. During deceleration with the throttle valve closed, current to the fuel injectors iscutoffto improvefuel economyat
speeds over 970 rpm ('97 - 98 models), 920 rpm ('99 - 00 modelsl.
. Fuel cut-off action also takes place when engine speed exceeds 6,500 rpm ('97 - 98 models), 6900 rpm ('99 - 00
models), regardless of the position of the throttle valve, to protect the engine from over-rewing.
With Ay'T model. the PCM cuts the fuel at engine speeds over 5,000 rpm when the vehicle is not moving.*'
4,./C Comoressor Clutch Relav
When the ECM/PCM receives a demand for cooling from the air conditioning system, it delays the compressor from
being energized, and enriches the mixture to assure a smooth transition to the Ay'C mode.
Evaporative Emission (EVAP) Purge Control Solenoid Valve
When the engine coolant temperature is above 154"F (68'C), the ECM/PCM controls the EVAP purge control solenoid
valve which controls vacuum to the EVAP purge control canister,
Alternator Control
The system controls the voltage generated at the alternator in accordance with the electrical load and driving mode.
which reduces the engine load to improve the fuel economy.
PCM Fail-saf e/Back-up Functions
1. Fail-safe Function
When an abnormality occurs in a signal from a sensor, the ECM/PCM ignores that signal and assumes a pre-pre
grammed value for that sensor that allows the engine to continue to run.
2. Back-up Function
When an abnormality occurs in the ECM/PCM itself, the fuel injectors are controlled by a back-up circuit independent
of the system in order to permit minimal driving.
3. Self-diagnosis Function IMalfunction Indicator Lamp (MlL)l
When an abnormality occurs in a signal from a sensor, the ECM/PCM supplies ground for the MIL and stores the DTC
in erasable memory. When the ignition is initially turned on {ll), the ECM/PCM supplies ground for the MIL for two
seconds to check the MIL bulb condition.
4. Two Trio Detection Method
To prevent false indications, the Two Trip Detection Method is used for the HO2S*1, fuel metering-related. idle control
system, ECT sensor and EVAP control system self-diagnostic functions. When an abnormality occurs, the ECM/PCM
stores it in its memory. When the same abnormality recurs after the ignition switch is turned OFF and ON (ll) again,
the ECM/PCM informs the driver by lighting the MlL. However, to ease troubleshooting, this function is cancelled
when you jump the service check connector, The MIL will then blink immediately when an abnormality occurs.
5. Two (or Three) Driving Cycle Detection Method {'97 model)
A "Driving Cycle" consists of starting the engine, beginning closed loop operation, and stopping the engine. lf misfir-
ing that increases emissions or EVAP control system malfunction is detected during two consecutive driving cycles.
or TWC deterioration is detected during three consecutive driving cycles, the ECM/PCM turns the MIL on. However, to
ease troubleshooting, this function is cancelled when you jump the service check connector. The MIL will then blink
immediately when an abnormality occurs.
*1: '97 - 98 models*2: '99 - 00 models
5.
www.emanualpro.com

PGM-FI System
Powertrain Control Module {PCM} -'97 Model
NOTE: lf this symptom is intermiftent, check for a loose fuse No. 25 METER (7.5 A) in theunderdash f{rse/relay box, a poor connection at PCM terminal A18, or an intermittentopen in the GRN/ORN wire between the PCM (A18) and the gauge assembly.
PCM OON ECTOR A {32P}
Wire side of female terminals
PCM CONNECTOR A {32PI
Wire side ot temale terminals
11-42
The Malfunction lndicator LamD(MlL) nev6r comes on {even lortwo seconds) after ignition isturned on (lll, or it's on dimlyand flickers.
Turn the ignition switch ON {ll}.
- Rep.ir short or opon in thowire batween No. 25 METER(7.5 Alfuso and gauge a$€m-bty.- R6pl.c€ No. 25 METER 17.5 Alfus€.
ls the charging system light on?
Try to stan the engine.
Does the engine start?
Chock tor.n open in th6 wire3{PG1, PG2linesl:1. Turn the ignition switch ON (ll).2. Measure voltage betweenbody ground and PCM con-nector terminals A10 and A23individually.
Check for an op€n in the wir6 orbulb (MlL lin€l:1. Turn the ignition switch OFF.2. Connect the PCM connectorterminal A18 to body groundwith a iumper wire.3. Turn the ignition switch ON {ll).
n€peir open in tho wirelslhwoon PCM and Glol (loc!t.d
at thc tha.mo3tat houling thrthtd moro th.n 1.0 V.
ls thore l€ss than 1.0 V?
Substituto . known-good PCMand r€check. ll symptom/indica-tion goss away, rcplaca the origi-nal PCM.
- R6pai. open in th. wileibelwoon rcM lAl8l dnd g.ugea3rombly.- Roolac€ the MIL bulb.
ls the MIL on?
Substitut6 a known-good PCMand rocheck. ll 3ymptom/indica-tion goes away, replace the o.igi-n.l PCM.
PGl IBLKI
www.emanualpro.com

PGM-FI System
Tho Maltunction Indicator Lamo(MlL) n6Yor como3 on leven lortwo laconds) rft6r tho ignhion isturnod ON {lll.
Turn th6 ignition switch ON (ll).
- Repair lhort or opcn in thowire between the No. 25METER 17.5 Al fu3e snd thegauge assembly.- Repl.co the No. 25 METER17.5 Al fus€.
ls the low oil pressure light on?
Try to start the engine.
Chock for an opsn in th€ wiro orbulb {MlL line,:1. Turn the ignition switch OFF.2. Connect the ECM/PCM con-nector terminal A18 to bodyground with a iumper wire.3. Turn the ignition switch ON (ll).
Rep.ir open in the wi.osbotween the ECM/FCM lA18land the gaugo rasombly.Roplece the MIL bulb.
ls th6 MIL on?
Substitute a known-good ECM/PCM and rochock. lf rymptom/indication goes eway, replacetho o gind ECM/PCM.
Turn the ignition switch OFF.Inspect the Fl E/M 115 A) tusein the undeFhood fuse/relaybox.
- Repair short in the wirebetween lhe Fl E/M (15 AlfusG and the PGM-Fl m.in.slay.- Roplsce th€ Fl E/M (15 Alfu3€.
Inspect the No. 13 FUEL PUMP(15 A) fuse in the under-dashfuse/relay box.
- Repair short in th6 wirebetween tho No. 13 FUELPUMP 115 A) luse and thePGM-FI main .elay.- ReDlace tho No. 13 FUELPUMP 115 Al tuse.
Engine Gontrol Module/Powertrain Control Module (ECM/PCM) -'98 - 00 Models
NOTE:. lf this symptom is intermittent, check tor:- A loose Fl E/M {15 A) fuse in the under-hood fuse/relay box- A loose No. 25 METER {7.5 A) fuse in the under-dash fuse/relay box- A loose No. 13 FUEL PUMP (15 Alfuse in the underdash fuse/rolay box- An intermiftent short in the wire between the ECM/PCM (A18) and the gauge assem-
- An int€rmiftent short in the wire between the ECM/PCM (C19) and the MAP sensor- An intermiftent short in the wire between rhe ECM/PCM (C28), the TP sensor, theEGR valve lift sensor and/or {uel tank Dressure sensor- A laulty PGM-FI main relay
ECM/PCM CONNECTOR A (32P}
Wire side of female terminals
(To page 11-871
www.emanualpro.com

PGM-FI System
Engine Control Module/Poweftrain Control Module (ECM/PCM) -'98 - 00 Models (cont'dl
NOTE:. When there is no Diagnostic Trouble Code IDTC) stored, the MIL will stay on iI the SCSservice connector is connected and the ignition switch is ON (ll).. lf this symptom is intermittent, check for:- An intermittent short in the wire between the ECM/PCM (A10) and the service checkconnoctor- An intermittent short in the wire between the ECM/PCM (At8l and the gaugeassemDty. See the OgD ll scan tool or Honda PGM Tester user's manuals for specific operatingrnstructions.
ECM/FCM CONNECTOF A {32P)
Wire side of femsle t6rminals
The Malfunction lndicator LamolMlll 3lays on or comes on aftertwo 3econds.
Check the Dirgnostic TroubloCod€ (DTCI:'1. Connect a scan tool or HondaPGM Tester.2. Turn the ignition switch ON (ll).3. Read the DTC with the scantool or Honda PGM Tester.
Go to troublGhooting procadura.(3€c prg€ l lS0l
check tho 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).
Ropair op.n ol Bhort in wirob.twe.n thc ECM/FCtrl (A21)
and D.i. Link Connoctor.Go to troublo3hootlng proc€-dur6. lt o pag. 11.6lrl
Does the MIL indicate any DTC?
Try to start the engine.
Sub3titute r known"good ECM/PCM .nd roch.ck. lt .ymptom/indic.tion gooa awsy, repl.cothe origin.l ECM/PCM.
Does the engine stan?
Check tor a 3hort in the wireISCS linel:1. Turn the ignition switch OFFand turn the ignition switchoN { ).2- Measure voltage betweenbody ground and the ECM/PCi, conneclor terminal A10.
Ropria ahort to body ground intho wi.c Mwe.n tho ECM/PCMlA10l and aarvic. check connsc-tor.
lTo page 1l-89)
11-88
www.emanualpro.com

PGM-FI System
Manifold Absolute Pressure (MAPI Sensor
The scan tool indicates Diagnostic Trouble Code (DTC) POl07: A low input (high vacuum) problem in theManifold Absolute Pressure (MAP) sensor,
The MAP sensor convens manifold absolute pressure into electrical signals and inputs the ECM/pCM.
OUTPUIVOLTAGE
tvl3.s
3.0
2.5
2.O
1.5
1.0
0.5
o .5 ro- 15^ 1olin.H9) GAUGEREADIT{G
lmmHgl
3025
100 200 300 a00 5oo 6fi, 7d)
MAP SENSOR 3P CONNECTOR IC131I
vccl(YEL/RED}
Th6 MIL has b€en reoorted on.DTC P0107 is 3tored.
Problom verification:1. Turn the ignition switch ON lll).2. Check the lvlAP with the scanroot.
lrtormittem tailu.e, lystam b OKat thb timo. Check tor poor con-noctions or loosa wird at C131(MAP rensor) and rt the ECM/PCM.
ls approx. 101 kPa (760 mmHg,30 in.Hg),2.9 V indicated?
Check for an op6n in wi.o IVCC1linel:1. Turn the ignition switch OFF.2. Disconnect the MAP sensorconnector,3. Turn the ignition switch ON {ll}.4. Measure voltage between theMAP sensor connector No. 1termanal and No. 2 terminal.
Roprir op€n in the wir6 bstweentho ECM/PCM (D4, C19*l and theMAP sensor.
ls there approx. 5 V?
(To page 11-91)
11-90
Wiro side ol temale terminals
www.emanualpro.com

PGM-FI System
Manifold Absolute Pressure (MAP) Sensor (cont'd)
[tn,t nn-] The scan tool indicates Diagnostic Trouble Code (DTC) P0108: A high voltage (low vacuum) problem in the|jg Manifold Absolute Pressure (MAP) sensor.
MAP SENSOR 3P CONNECTOR IC131I
Wire side of female terminals
vcclIYEL/RED}
PCM CONNECTOR D I16PI
JUMPER WIRE
sGlIGRN/WHTI
Wire side of lemale termin6ls
1
(To page 11,93)': '98 - 00 models
1-92
tcRN/wHrll IIRED/GRN|
The MIL has boen reported on.DTC m108 is slored.
Problem veritication:1. Start the engine. Hold theengine at 3,000 rpm with noload (in Park or neutral) untilthe radiator fan comes on, thenlet it idle.2. Check the MAP with the scantool.
Intermittent tailuro, system i3 OKat this time. Check tor ooor con-nections or loose wires at C131IMAP s6nsor) snd the ECM/rcM.
ls 101 kPa {760 mmHg,30 in.Hg),2.9 V or higher indicated?
Check Ior an open in the MAPsensor:1. Turn the ignition switch OFF.2. Disconnect the MAP sensor3P connector.3. lnstall a jumper wire betweenthe MAP sensor 3P connectorterminals No.3 and No.2.4. Turn the ignition switch ON {ll).5. Check the MAP with the scantool.
ls 10'l kPa (760 mmHg,30 in.Hg),2.9 V or higher indicated?
Check for an open in wire (SGlliDel:1. Remove the jumper wire.2. Measure voltage between theMAP sensor 3P connector ter-minals No. 1 and No- 2.
R6p.ir open in the wire betwoenthe ECM/PCM (D12, CTrl and theMAP sensor.
ls there approx. 5 V?
Check for an open in the wire(MAP line):1. Turn the ignition switch OFF.2. lnstall a iumper wire on thePCM connectors between D3and D12.3. Turn the ignition switch ON (ll).4. Check the MAP wirh the scantool.
Ropair opon in the wire betweenthe PCM {D3, .nd the MAP son-3('t.
ls 101 kPa 1760 mmHg, 30 in.Hg),2.9 V or higher indicated?
YES
www.emanualpro.com

PGM-FI System
Manifold Absolute Pressure (MAP) Sensor (cont'dl
The scan tool indicates Diagnostic Trouble Code (DTC) P1128: Manifold Absolute pressure (MAp) lower thanexoected.
The scan tool indicates Diagnostic Trouble Code (DTC) P'l129: Manifold Absolute Pressure (MAP) higher thanexpected.
l
- The MIL has be6n r€ported on.- DTC Pl128 is stored.
Problom verification:1. Turn the ignition switch ON 1lli.2. Check the MAP with the scantool,
ls 54.1 kPa (406 mmHg, 16.0 in.Hg),1.61 V or higher indicated?I to.mittent failure, 3ydom i! OKal thbtimc,
- The MIL has boen reportod on.- DTC Pl129 is stored.
Problem veritication:1. Start the engine. Hold theengine at 3,000 rpm with noload lin Park or neutral) untilthe radiator fan comes on,then Iet it idle.2. Check the MAP with the scantool,
ls 43.3 kPa (325 mmHg, 12.8 in.Hg),'1.32 V or less indicated?Intarmittani fuilure, systom i3 OKat this time.
11-94
www.emanualpro.com

PGM-FI System
Intake Air Temperature (lAT) Sensor (cont'dl
The scan tool indicates Diagnostic Trouble code (DTC) P0112: A low voltage (high temperature) problem in theIntake Air Temperature 0AT) sensor circuit.
The IAT Sensor is a temperature dependant resistor (thermistor). The resistance of tho thermistor decreases as the intakeair temperature increases as shown below.
RESISTANCE IKO)
i')
)2 /
A tAr
9) (RED/YEU
-L
-. 32 aa rorr 1?a 2ra 2aa f.el-m 0 20 rto ao i0 too l2ofcl
INTAKE AIR TEMPERATUR€
It the engine is warm, it will b€ high-er than ambient temperature.
IAT SENSOR 2P CONNCCTOR (C'33I
- The MIL has been reDoned on.- OTC m112 is stored,- Or from Probable Caus€ List.
Problem vsrification:1. Turn the ignition switch ON flt).2. Check the IAT with the scantool.
ls 302'F (150'C) or higher (orH-Limit in Honda mode ofPGM Testeri or 0 V indicated?
ls the correct ambient temper-ature indicated,,?Beploce tho IAT sensor.
Intermittent failure, system i3 OKat this time. Ch6ck for poor con-nectiona o. loose wires rt C133{lAT s€nsorl and rt th6 ECM/pCtr4.Check for a short in the IAT sen-sot:1. Disconnect the IAT sensor 2p
2. Check the IAT with the scantool.
ls 302"F {150"C) or higher {orH-Limit in Honda mode ofPGM Tester) or 0 V indicated?Raplace the lAT aensor.
Ch€ck for a short in the wir6 llAtlinel:1. Turn the ignition switch OFF.2. Disconnect the ECM/PCM con-nector {D (16P}, C (31P)').3. Check for continuity betweenthe IAT sensor 2P connector terminalNo.2 and body ground.
Repair short in the wi.o botweenth6 ECM/rcM {D8, C25*l and th6IAT 3ensor.
Substitute a known-good ECM/PCM and recheck. lf normel IATis indicaled, replace the originalECM/PCM,
*: '98 - 00 models
1 1-96
Wi16 side of femsle terminals
www.emanualpro.com