1998 HONDA CIVIC Trouble shooting

Troubleshooting
Central Processing Unit (CPUI
Diagnostic Troublo Code IDTC) 81: CPU Disgnosis
- With the ignition switch ON{lll. ABS indicator light doesnot go oft.- With tho SCS servi@ connec-tor conn€cted lsee page 19{6},DTC 81 is indicated.
P.oblem vedfication:1. Erase the DTC.2. Test-drive the vehicle.3. Make sure that the ABS indi,cator light comes on and DTC81 is indicated.
ls DTC 81 indicated?R€pllc6 th. ABS control unh.
The system k OK rt this time.
19-74

Troubleshooting
SymptomProbable Cause
Water leaks1. Clogged drain tube.
2. Gap between glass weatherstrjp and roof panel.
3. Defective or improperly installed glass weatherstrip.
4. Gap between drain seal and roof panel.
Wind noise'1. Excessive clearance between glass weatherstrip and roof panel.
Motor noise1. Loose motor.
2. Worn gear or bearing.
3. Cable assembly deformed.
Glass does not move, but motor turns'1. Clutch out of adjustment.
2. Foreign matter stuck between guide rail and slider.
3. lnner cable loose.
4. Cable assembly not attached properly.
Glass does not move and motor does not turn
{glass can be moved with moonroof wrench)
1. Blown fuse,
2. Faulty switch.
3. Battery run down.
4. Defective motor.
5. Faulty relay.
D
Glass Height Adjustment
The roof panel should be even with the glass weather-
strip, to within 1.7 :lr3 mm (0.07 :3:31 in.) all the way
around. lf not, open the giass fully, and:
GLASS WEATHERSTRIP
1. Remove the bracket cover.
Loosen the nuts, and install the shims between the
glass frame and glass bracket as shown.
Shim thickness: Front max.3 mm 10,12 in.l
Rear max. 2 mm 10.08 in.)
Repeat on opposite side i{ necessary.
)
5x1.0mm9.8 N.m 11.0 kgf m,7.2 rbtft)
SRACKETCOVEB
----------1>
6x1.0mm9.8 N.m {1.0 kgtm,7.2 tbf.ft)
1.7 tl.8 mm
{0.07 :3 3i in.}
20-51

Heater
lllustrated Index
'96 - 98 Models ................................ 21'2
'99 - 00 Models ................................ 21'3
Circuit Diagram
'96 - 98 Models .....21-4
'99 - 00 Models ................................ 21-5
Troubleshooting - '96 - 98 Models
Symptom Chart ............................... 21-6
Heater Control Panel Input/
Output Signals ..............,.............. 21-7
Flowcharts
Blower Motor Speed ................... 21-8
Bf ower Motor ,...21'10
Mode Control Motor ............... ,.'.' 21-13
Recirculation control Motor ....... 21-16
Heater Control Panel ................ ... 21 -14
Troubleshooting - '99 - 00 Models
Symptom Chart ............................... 21-19
Seff-diagnosis Function ............,,,.... 21-20
Flowcharts
Air Mix Control Motor ......,.......... 21-21
Mode Control Motor ............... ..... 21 -25
Recirculation Control Motor ....... 21-27
Bf ower Motor Speed .............. .....21'29
Bf ower Motor ....21-31
Heater Control Panel ................,.. 21-35
Heater Control Panel Input/
Output Signals ............................. 21-36
Blower Unit
Repf acement .........21-37
Overhaul ................ 21-38
* Heater Unit
Replacement ....'....21-39
overhaul """" """' 21-4'l
Heater Control Panel
Repfacement .........21'42
Overhaul -'96 - 98 Models ........... 21-43
Temperature Control
Adjustment - '96 - 98 Models """" 21-44
Adiustment - '99 - 00 Models .......21-45
Air Mix Control Motor
Test - '99 - 00 Models ...........' .......21'46
Replacement - '99 - 00 Models ....21'46
Mode Control Motol
Test ................, .,...'.21'47
Replacement '.'."...21-47
Recirculation Control Motor
Test ................. .......21-48
Repf acement ......." 21-48
Relays
Test ................. .......2'l-49
Heater Fan Switch
Test - '96 - 98 Models ............. .......21-49
Mode Control Switch
Test -'96 - 98 Models ..........."....... 21-50
Power Transistor
Test - '99 - 00 Models ....'........ ....".21-50
*: Read SRS Drecautions before working in this area.

Troubleshooting -'96 - 98 Models
Symptom Chart
NOTE;
. Check the engine coolant level. and allow the engine to warm up before troubleshooting.
. Any abnormality must be corrected before continuing the test.
. Because of the precise measurements needed. use a multimeter when testing.
o Before performing any troubleshooting procedures check:- Fuses No. 41 11.5 Al, No. 55 (40 A) in the under-hood fuse/relay box. and No. 17 (7.5 A) in the under-dash fuse/relay
box- Grounds No. G401, G402- Cleanliness and tightness of all connectors
SymptomRomedy
Hot air flow is low.Blower motor runs. but one or more
speeds are inoperative.
Perform the procedures in the flowchart (see page 21-8).
Blower runs properly.Check for the following:. Clogged heater duct. Clogged heater outlet. Incorrect door position
No hot air flow.Blower motor does not run at all,Perform the procedures in the flowchart (see page 21-10).
Blower motor runs.Check for the following:. Clogged heater duct. Clogged blower outlet. Clogged heater valve. Faultv air mix door. Heater valve cable adjustment (see page 21-44). Air mix control cable adiustment (see page 2'l-441. Faulty cooling system thermostat (see section 10). Clogged evaporator (with air conditioning). Frozen evaporator {with air conditioning)
Mode control motor does not run, or one or more modes
are inooerative.
Perform the procedures in the flowchart (see page 21-13).
Recirculation control door does not chanqe between
FRESH and RECIRCULATE.
Perform the procedu.es in the flowchan (see page 21-16).
Both heater and A,/C do not work.Perform the procedures in the flowchart (see page 21-18),
21-6

Troubleshooting -'96 - 98 Models
Blower Motor Speed
HEATER FAN SWITCH 6P CONNECTOR
Wire side of female terminals
21-a
Blower motor runs. but one orrnore speeds are inoperative,
Chsck for a short or an open inthe wire{s}:Turn the ignition switch ON {ll),and the heater fan switch OFF.
Does the blower motor run?
Check for a shon in th6 wirels):1. Turn the ignition switch OFF.2. Disconnect the blower motor2P connector,3. Remove the center dashboardlower cover (see section 20),and disconnect the heater lanswitch 6P connector,4. Disconnect the blower resistor 4P connector,5. Check for continuity betweenthe No. 2,3, 4 and 5lerminalsof the heater fan switch 6Pconnector and body ground
individually.
ls there continuity?Reolace the heater fan switch,
Repair short in the wire(s)beiween the blower resistor, theheater tan switch and the blowermotor,
To page 21 9

Troubleshooting -'96 - 98 Models
Blower Motor
BLOWER MOTOR 2P CONNECTOR
Wi.e side of fernale terminals
f=
l1l
r,l
ruumifalulau**'
I
Fl gr-urwnr
l1|_-_-l
t4 ,t
I
glower motor does not run at all.
Check the No.55 (40A)luse in theunder hood fuse/relay box, andthe No. 17 (7.5 A) luse in theundeFdash luse/relay box.
Repl.ce th. fuse{rl, .nd rochack.
Check the blower motor:1. Connect the No. 2 terminal ofthe blower motor 2P connoctor to body ground with a
lumper wrre.2. Turn the ignition switch ON (ll).
Does the blower motor run?
Chock for an opsn in the wire:1. Disconnect the ,umper wireand the blower motor 2P con-nector,2. Measure the voltage betweenthe No. 1 terminal and bodyground.
ls there battery voltage?
Ch6ck tha blower motor relay:1. Turn the ignition switch OFF.2. Remove the blower motorrelay from the under-hoodfuse/relay box, and test it (see
page 21-49).
Replace tha blower moior reley.
To page 21-11
fo page21'12
21-10

Troubleshooting -'96 - 98 Models
From page 21-10
Check the under-hood fuse/relayDOX:N/leasure the voltage between theNo. 3 terminal of the blowermotor relay 4P socket and bodyground,
ls there baftery voltage?
Check lor an open in th€ wire:1. Turn the ignition switch ON (ll).
2. Measure the voltage betweenthe No. 4 terminal of the blow-er motor relay 4P socket andbody ground.
Repair open in tho wire betweenthe No. 17 fuss and tho blowelmotor rclay,
Check for en opon in the wire:1. Turn the ignition switch OFF.2. Check for continuity betweenthe No. 2 terminal of the blow-er motor relay 4P socket andbody ground.
Check foi an open in the wirebetwe€n the blower motor relavand body glound. lf the wiro isOK, check fo. poor ground atG{01 and G4O2.
ls there continuity?
Repair open in the BLU/WHTwire b€tween the blower motorrelav and the blower motor.
Blower Motor (cont'dl
BLOWER MOTOR RELAY 'P SOCKET
1211
tt-l_T
trv)
i
21-12

Troubleshooting -'96 - 98 Models
Mode Control Motor lcont'dl
From page 2l-13HEATER CONTROL PANEL lilP CONNECTOR
Wire side of lemaie terminals
Check tor a short in the wi.e(s):1. Remove the center dashboardlower cover (see section 20),and disconnect the heater con-trol panel 14P connector.2. Check for continuity betweenthe No. 1, 4, 7, 8 and 9 termi-nals and body ground individ-
Raprir.ny short in the wire(s)betw€en the mode control motorand the heater control panel.
Check for a shon to power:
Check the same wires {or voltage.
Repair short to pow6r in thewiro(3) betwoen the mode con-lrol motor .nd tha heate. controlprnel, This short also damag.stho heater cont.ol prnel. Repailthe short to power b€{ore replac-ing the heeter conlrol pan6l.
ls there any voltage?
To page 21 15
21-14