Page 1177 of 2189

Brake Booster InsPection
FunctionalTest
1. With the engine stopped, depress the brake pedal
several times to deplete the vacuum reservoir, then
depress the pedal hard and hold it for 15 seconds lf
the pedal sinks' either the master cYlinder is
bypassing internally, or the brake system (master
cylinder. lines. modulator, proportioning control
valve, or caliPer) is ieaking.
2. Start the engine with the pedal depressed lf the
pedal sinks slightly, the vacuum booster is operating
normally. lf the pedal height does not vary, the
booster or check valve is faultY.
3. With the engine running. depress the brake pedal
lightly. Apply just enough pressure to hold back
automatic transmission creep. lf the brake pedal
sinks more than 25 mm (1.0 in.) in three minutes,
the master cvlinder is faulty. A slight change in
pedal height when the A'lC compressor cycles on
and off if normal. (The A/C compressor load
changes the vacuum available to the booster')
Leak Test
1. Depress the brake pedal with the engine running.
then stop the engine. lf the pedal height does not
vary while depressed for 30 seconds, the vacuum
booster is OK. lf the pedal rises. the booster is
faulty.
2, With the engine stopped, depress the brake pedal
several times using normal pressure When the
Dedal is first depressed, it should be low On con-
secutive applications, the pedal height should grad-
uallv rise. lf the pedal position does not vary, checK
the booster check valve.
l./
19-23
Booster Check Valve Test
1. Disconnect the brake booster vacuum hose at the
booster.
2. Stan the engine and let it idle. There should be vac-
uum. lf no vacuum is available, the check valve is
not working properly. Replace the brake booster
vacuum hose and check valve, and retest.
BRAKE BOOSTERVACUUM HOSE(Check valve
built-in)
Page 1209 of 2189

Diagnostic Trouble Code (DTCI
Diagnostic Trouble Code {DTC) Indication
NOTE: This operation can also be carried out with the Honda pGM Tesrer.
l connect the scs service connector to the service check connector inside the passenger,s side kick panel.
2. Turn the ignition switch ON (||). but do not start the engine.NOTE: Do not depress the brake pedal when turning the ignition switch.
3 Record the brinking frequency of the ABS indicator right. The brinking frequency indicates the DTc.
4, Turn the ignition switch OFF, and remove the SCS service connector.NorE: The Mslfunction Indicator Lamp (MlL) will stay on after the engine is started if the scs service connector isconnected.
5. Erase the DTC.
Condhions for DTC indication. The vehicle is stoDDed.. The SCS service connector is connected before the ignition switch is turned ON fll).. The brake pedal is released.. Th€ SCS service connector remains connected during this procedure
The DTG indication stops 8nd the ABs conltol unit executes the softwaro tunqtion if at least one of the following condi-tions b satisfied:
o The vehicle is not stoDoed.' The ABS control unit receives the normat signal (which is for the ABS controt unit) from a Honda pGM Tester.. The SCS service connector is disconnected during this procedu.e,
u.s.A.
@
CANADA
@
SERVICE CHECKCONNECTOR {2PISCS SERVICE CONNECTOR07PAZ - 0010100
ABS INDICATOR LIGHT
DTC : 3 3
A8S INDICAIOR LIGHT
Snilion swirch
' when the ignition switch is turned oN (ll), the ABs indicator light comes on to check the bulb. Do not count it as a DTc.o The ABS control unit can memorize any number of DTCs.. The new DTC is not memorized when the ABS control unit has already memorized the same DTC,.lftheDTCisnotmemorized,theABSindicatorlightstaysONafteritgoesofffor3.6seconds.
19-56
Page 1210 of 2189

LJDTG Erasure
1.
2.
Connect the SCS service connector to the service check connector inside the passenger's side kick panel.
Depress the brake pedal.
Turn the ignition switch oN (ll) while holding the brake pedal, but do not start the engine. The ABS indicator light
goes off after two seconds.
After the indicator light goes off, release the brake pedal The indicator lightcomeson after four seconds
After the indicator light comes on, depress the brake pedal again. The indicator light goes off again after four sec-
onds. The brake pedal is still depressed.
4.
5.
\t
6. After the jndicator light goes off, release the brake pedal again'
7. After four seconds, the indicator light blinks twice for 0 3 second and the DTC is erased
8. Confirm the DTC indication, and check that the DTC was erased
NOTE: Always maintain these steps. lf you disconnect the scs service connector and/or fail to operate the brake pedal
according to the indicator light indication, the DTC will not be erased
Conditions for DTC erasure
o The vehicle is stopped.
. The SCS service connector is connected before the ignition switch is turned ON {ll)
. The brake pedal is depressed before the ignition switch is turned ON (ll)'
. The SCS service connector remains connected during this procedure
The DTC erasure stops and ABS control unit executes the software lunction it at least one ot the following conditions is
satisfied:
o The vehicle is not stopped.
. The SCS service connector is disconnected during this servace'
.TheABscontro|unitreceivesthenormaIsigna|(whichisfortheAEscontro|unit)fromaHondaPGMTester'
. The brake pedal is not operated according to the indicator light indication
. The DTC erasure is finished
ABS INDICATOR LIGHT
OFF
DEPRESS
BRAKE PEDAL
RELEASE
0.3sec
lqnition switchoN (I)
J
19-57
Page 1957 of 2189

- How the Circuit Works
Battery voltage is supplied through tuse 56 to the
A,/C compressor clutch r€lay contacts at all times.
With the ignition switch in ON (ll), vollage is applied
to the coil of the A,/C compressor clutch relay
through fuse 17. When you push the A,/C switch
ON, and the heater fan switch is in position | , 2, 3,
or 4, a "ground" input is provided to the engine
control module (ECM) or powertrain control module
(PCM) through the l'lC thermostat and the l'lC
pressure switch.
The A,/C compressor clutch relay is grounded by the
engine control module (ECM) or powertrain control
module (PCM). When energized, the A'lC
compressor clutch relay allows battery voltage to
turn on the A,/C comDressor clutch.
The A,/C ON indicator light comes on when the A,/C
system is requested.
A,/C Thermostat
The A'lC thermostat is located on the evaoorator
housing. The A,/C thermostat turns off the A,/C
compressor clutch if the temperature at the
evaporator goes below 3'C (37'F). This prevents
condensation from freezing on the evaporator fins
and blocking the air delivery into the passenger
compartment. The blower motor will keep running
when the sensor turns off the comDressor.
A,/C Pressure Switch
The fuC oressure switch is located in the condenser
outlet line where refrigerant is in a high
temperature/high pressure liquid state. The switch
will sense abnormally high or low pressure, and
open the circuit. This removes ground, and the
compressor will stop running.
Thermal Protectot
The thermal protector, located on the A,/C
compressor, opens and turns the compressor off if it
senses high temperature. Once the compressor
cools, the switch will close and the compressor will
begin running again.
Refer to the Service Manual (Section 22,
Air Conditioning) for specific tests or
troubleshooting procedures.
62-3
Page 1961 of 2189

- How the Circuit Works
Radiator Fan
Voltage is provided at all times to the radiator fan
relay (contacts) through fuse 57. With the ignition
swilch in ON (ll), voltage is provided to the coil of
the relay through luse 17.
The radiator tan relay can be grounded through
either the engine coolant temperature switch or the
engine control module (ECM) or powertrain control
module (PCM).
The engine coolant temperature switch grounds
the radiator fan relay (coil) when the engine
coolant temperature exceeds 199'F (83'C). The
switch opens when coolanl temperature
decreases 3'- 8'C.
Condenser Fan
Voltage is provided at all times to the condenser fan
relay (contacts) through fuse 56. With the ignition
switch in ON (ll), voltage is provided to the coil of
the relay through fuse 17. When you push the A'lC
switch and put the heater fan switch in 1, 2,3, o( 4
position, the ly'C thermostat comes on, the
condenser fan relay energizes, and the condenser
fan motor runs.
A,/C Thermostat
The A,/C thermostat is located on the evaporator
housing. The A,/C thermostat tums off the A/C
compressor clutch if the temperature at the
evaporator goes below 3'C (37'F). This prevents
condensation from freezing on the evaporator fins
and blocking the air delivery into the passenger
compartment. lf the temperature goes below 3'C
(37"F) tuming off the Ay'C thermostat, ground will be
removed from the condenser fan relay. This will
deenergize the relay and remove voltage from the
condenser fan motor causing the fan to stop running.
Reter to the Service Manual (Section 23, Eleckical)
for specific tests or troubleshooting procedures.
63-3