Honda Civic. Manual — part 753

compressor
clutch does
not engage
(but both fans
run with the
A/C on)

A/C compressor clutch circuit
troubleshooting (see A/C
COMPRESSOR CLUTCH
CIRCUIT
TROUBLESHOOTING )

INFORMATION )

Blown fuse No. 12 (7.5 A)
in the under-hood
fuse/relay box, and No. 36
(10 A) in the under-dash
fuse/relay box

Cleanliness and tightness
of all terminals

A/C system
does not come
on (both fans
and the A/C
compressor do
not work);
heater is OK

A/C signal circuit
troubleshooting (see A/C
SIGNAL CIRCUIT
TROUBLESHOOTING )
A/C pressure sensor
troubleshooting (R18A1
engine): A/C pressure sensor
circuit low voltage (see DTC
P0532: A/C PRESSURE
SENSOR CIRCUIT LOW
VOLTAGE ), A/C pressure
sensor circuit high voltage (see
DTC P0533: A/C
PRESSURE SENSOR
CIRCUIT HIGH
VOLTAGE )
A/C pressure sensor
troubleshooting (K20Z3
engine): A/C pressure sensor
circuit low voltage (see DTC
P0532: A/C PRESSURE
SENSOR CIRCUIT LOW
VOLTAGE ), A/C pressure
sensor circuit high voltage (see
DTC P0533: A/C
PRESSURE SENSOR
CIRCUIT HIGH

HVAC DTCs (see
GENERAL
TROUBLESHOOTING
INFORMATION )

Powertrain DTCs, R18A1
engine (see GENERAL
TROUBLESHOOTING
INFORMATION ),
K20Z3 engine (see
GENERAL
TROUBLESHOOTING
INFORMATION )

Cleanliness and tightness
of all terminals

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)

SYSTEM DESCRIPTION

The air conditioning system removes heat from the passenger compartment by
circulating refrigerant through the system.

Fig. 7: Heating/Air Conditioning System Description

This vehicle uses HFC-134a (R-134a) refrigerant, which does not contain
chlorofluorocarbons. Pay attention to the following service items:

Do not mix refrigerants CFC-12 (R-12) and HFC-134a (R-134a). They are not
compatible.

Use only the recommended polyalkyleneglycol (PAG) refrigerant oil (SP-10)
designed for the R-134a A/C compressor. Intermixing the recommended
(PAG) refrigerant oil with any other refrigerant oil will result in A/C
compressor failure.

VOLTAGE )

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)

All A/C system parts (A/C compressor, discharge line, suction line, evaporator,
A/C condenser, receiver/dryer, expansion valve, O-rings for joints) are
designed for refrigerant R-134a. Do not exchange with R-12 parts.

Use a halogen gas leak detector designed for refrigerant R-134a.

R-12 and R-134a refrigerant servicing equipment are not interchangeable. Use
only a recovery/recycling/charging station that is U.L.-listed and is certified to
meet the requirements of SAE J2210 to service the R-134a air conditioning
systems.

Always recover refrigerant R-134a with an approved
recovery/recycling/charging station before disconnecting any A/C fitting.

OIL SEPARATOR

Oil emission from the A/C compressor to the A/C line is reduced by placing the oil
separator in the A/C compressor. This results in a thinner oil film inside of the heat
exchanger (A/C condenser and evaporator). Air conditioning efficiency is increased
without sacrificing engine performance.

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)

Fig. 8: Oil Separator System Description

A/C PRESSURE SENSOR

The A/C pressure sensor converts A/C pressure into electrical signals to the
ECM/PCM.

2008 Honda Civic EX

2006-08 HVAC Heating/Air Conditioning - Civic (All Except Hybrid)