1999 HONDA CIVIC engine coolant

GRADE LOGIC CONTROL SYSTEM
How it works:
The pCM compares actual driving conditions with driving conditions memorized in the PCM, based on the input from the
vehicle speed sensor, the throttle position sensor, the barometoric pressure sensor, the engine coolant temperature sensor,
the brake switch signal, and the shift lever position signal, to control shifting while a vehicle is ascending or descending a
slope, or reducing speed.
SIGNALS OETECTED
O.iving Resi3lence
Judgemenl ot Conirolling Arca
. Ascending mod€
lFuzzy loqicl. Gradual Ascending mode' Ste€p Ascending mode. Oescending mode. Gr.du.l Descending mode. Steep D6cending mode
14-15

Electrical Troubleshooting ('96 - 98 Models)
Troubleshooting Flowchart - Lock-up Control System
NOTE: Record all freeze data before vou troubleshoot.
Possible Cause
Faulty Lock-up cont.ol system
NOTE: Do not continue with this troublesnoonnoother DTCS have been corrected.until the causes of any
. OBD ll Sc6n Tool indicatG Codem7{0.. Self-diagnosis E indicator lightindicates Code 40.
Check tor Another Code:Check whether the OBD ll scantool or the E indicato, lightindicates another code.
Perform lhe Troublo3hooiingFlowchart tor the indicatedCode(s). Recheck for cod. P07il0lilol aftor iroubl€3hooting.
Does the OBD ll scan tool orthe E indicator light indicateanother code?
Tast Line Pressure:Measure the line pressure (seepage 14-119 and 14-120).
Repair tho hydreulic aystem a3necessary {3ee page 14-119).
Replace the Lock-up ControlSolenoid Valve Assembly andR6check;1. Beplace the lock up controlsolenoid valve Ay'B assembly(see page 14-105).2. Turn the ignitaon switch OFFand reset the PCM by removing the BACK UP (7.5 A) fusein the underhood fuse/relaybox for more than 10 seconds,3. Using the scan tool, check tobe sure that the engine coolant temperature is in 176'F(80'C) and above.4. Drive the vehicle at 55 mph(88 km/h) constantly for morethan one minute.5. Recheck for code P0740 (40).
Does the OBD ll scan toolindicate code P0740 {40)?The systom k OK at this time.
l'.
14-74

Description
Electronic Control System ('99 - 00 Modelsl (cont'dl
Grade Logic Control System
How it works:
The PcM compares actual driving conditions with memorized driving conditions. based on the input from the vehiclespeed sensor, the throttle position sensor, the manifold absolute pressure sensor, the engine coolant temperature sensor,the brake switch signal, and the shift lever position signal, to control shifting while the vehicle is ascending or descendinga slope.
Ascending Control
When the PCM determines that the vehicle is climbing a hill in E position, the system selects the most suitable shiftschedule (pulley ratio) according to the magnitude of a gradient. so the vehicle can run smooth and have more powerwhen needed. There are three ascending modes with different shift schedules according to the magnitude ot a gradient inthe PCM.
Descending Control
when the PCM determines that the vehicle is going down a hill in E position. the system selects the most suitable shiftschedule (pulley ratio) according to the magnitude of a gradient. This, in combinstion with engine braking, achievessmooth driving when the vehicle is descending, There are three descending modes with different shift schedules accord-ing to the magnitude of a gradient in the PCM.
L
14-206

Start Clutch Control@
T
Start Clutch Calibration Procedure
NOTE: When the following parts are replaced, the TCM
must memorize the feedback signal for the start clutch
control.
. TCM
. Transmissionassembly
. Stan clutch assembly
. Lower valve bodv assembly
. Engine assembly or overhaul
'96 Model Only
CAUTION: Do not uso this procsdure on'97 - (X) mod-
els or you will damage the transmission. On '97 - 00
models, the TCM or PCM memorizes ths loodback sig'
nals when you drive the vehicle.
1. Engage the parking brake, and block the front
wheels securely.
2. Connect the SCS service connector to the Service
Check Connector as shown. (The Service Check
connector (2P) is located under the dash on the
passenger's side of the vehicle.)
CONNECTOR07PAZ - lDl01(xt
Start the engine, and warm it up to normal operat-
ing temperature (the radiator fan comes on twice).
Fully depress the brake pedal and accelerator for 20
seconds in the E] position.
rl ,
CONNECTOR I2PI
14-293
7.
Shift into E o|. E position. To store the engine
negative pressure in memory. Iet the engine idle in
E or E position for one minute under the follow-
ing conditions:
. With the brake pedal depressed,
. with the y'\/c switch oFF.
. With the combination light switch OFF.
. With the heater fan switch OFF.
. Turn OFF all other electrical systems
NOTE: Start step 5 within 60 seconds after the radi-
ator fan goes off.
Shift into E position, and let the engine idle for two
minutes to store the feedback signal in memory
under the same conditions as in step 5.
Connect the Honda PGM Tester. Check that the TCM
has completed the start clutch calibration.
NOTE:
. The TCM will not store the feedback signal when
the CVT fluid temperature is below 40"C (104'F)
even if the engine coolant temperature reaches
the normal operating temperature.
. Repeat these procedures until the start clutch
calibration is completed-
Disconnect the SCS service connector from the
Service Check Connector.
'97 - 00 Models
The TCM ('97 - 98 models) and PCM ('99 - 00 models)
memorize the feedback signal when you drive the
vehicle as follows:
. After warming up the engine (the radiator fan
comes onl.
. Shift into E position.
. Turn OFF all electrical systems,
. Drive the vehicle up to the speed 37 mph (60
km/h).
. After the speed reaches 37 mph (60 km/h),
release the accelerator for 5 seconds.

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 -'99 - 00 Models
Symptom
Mode control motor does not run, or one or more modes are inoperat've'
Recirculation control door does not change between Fresh and Recirculate'
Blower motor only runs on high speed position; it does not run in any other speed positions
Blower motor does not run at all.
Both heater and Ay'C do not work
See pags
a1_tq
21-21
21-29
21-31
21 35
Symptom Chart
For electrical malfunctions which are indicated by the self-diagnostic system, refer to self-diagnosis function (see next
page).
Note these items before troubleshooting a symptom'
. Check the engine coolant level, and allow the engine to warm up before troubleshooting'
. Any abnormality must be corrected before continuing the test
.Becauseoftheprec|semeasurementsneeded,UseadigitaImu|timeterwithanoutputoflmAor|essatthe20ko
range when testing
. Before performing any troubleshooting procedures check:
- Fuses No. 41 115 Al, No 55 (40 A)]n the under-hood fuse/relay box' and No 17 (7 5 A) in the under-dash fuse/relav
box- Grounds No. G401, G402
- Cleanliness and tightness of all connectors
21-19

Heater Unit
Replacement
SRS components are located in this area. Review the
SRS component locations, precautions, and procedures
in the SRS section {24} before performing repairs or ser-
L Disconnect the negative cable from the battery.
2. Frcm under the hood, open the clamp, then discon-
nect the heater valve cable from the heater valve
arm. Turn the heater valve arm to the fully opened
position as shown.
When the engine is cool. drain the engine coolant
from the radiator (see section 10).
!@ Do not remove the radiator cap when
the engine is hot; the ongine coolant is under pres'
surg and could severely scald you.
CLAMP
HEATER VALVC CABLE
4. Disconnect the heater hoses from the heater unit.
CAUTION: Engine coolant will damage p8int.
Ouickly rinse any spilled engins coolant from painted
su aces,
NOTE: Engine coolant will run out when the hoses
are disconnected; drain it into a clean drip pan.
5. Remove the mounting nut from the heater unit.
NOTE: When removing the mounting nut, take care
not to damage or bend the fuel lines, the brake
lines, etc.
I x 1 .25 mm22 N.m {2.2 kgl.m, 16lblftl
21-39

Heater Unit
Replacement (cont'dl
6.
7.
8.
9.
Remove the dashboard (see section 20).
Remove the heater duct (see page 21-37) or evapo-
rator (see page 22-28).
Disconnect the connectors from the mode control
motor and air mix control motor ('99 - 00 models),
then remove the wire harness clips and wire har-
ness from the heater unit. Remove the clip from the
heater duct, then remove the two mounting nuts
and the heater unit.
6x1.0mm9.8 N.m 11.0 kgl.m,7.2 lbf.ftl
HEATER UNIT
lnstall in the reverse order of removal. Make note of
the following items.
Apply sealant to the grommets.
Do not interchange the inlet and outlet heater
hoses. Make sure that the clamps are secure.
Refill the cooling system with engine coolant
(see section 10).
Connect all cables, and make sure they are prop-
erly adjusted (see page 21-44 (96 - 98 models)
or page 21-45 ('99 - 00 models)).
Make sure that there is no air leakage.
21-40