air conditioning ACURA TL 1995 Service Repair Manual

25. Loosen the mounting bolt, lock bolt and adjusting

rod, then remove the alternator belt.

ADJUSTING

ROD
LOCK BOLT

8 x
1.25
mm

22 N-m (2.2 kgf-m,

16 Ibf-ft)

ALTERNATOR

BELT
MOUNTING BOLT

10 x
1.25
mm

44 N-m (4.5 kgf-m,

33 Ibf-ft)

26. Loosen the idler pulley center nut and adjusting bolt,

then remove the air conditioning (A/C) compressor

belt.

IDLER PULLEY

CENTER NUT

10 x
1.25
mm

44 N-m (4.5 kgf-m,

33 Ibf-ft)
ADJUSTING

BOLT

A/C COMPRESSOR

BELT
27. Disconnect the power steering pressure (PSP)

switch connector.

28. Remove the adjusting bolt, locknut and mounting

bolt, then remove the P/S pump belt and pump.

Do not disconnect the P/S hose.

ADJUSTING

BOLT
P/S PUMP
LOCKNUT

8 x
1.25
mm

22 N-m (2.2 kgf-m,

16 Ibf-ft)

PSP SWITCH

CONNECTOR

29.
P/S PUMP

BELT

MOUNTING BOLT

10 x
1.25
mm

44 N-m (4.5 kgf-m, 33 Ibf-ft)

Pull the carpet back to expose the secondary heated

oxygen sensor (Secondary HO2S) connector, then

disconnect the secondary HO2S connector.

SECONDARY

HO2S CONNECTORProCarManuals.com

PGM-FI System

System Description (cont'd)

3. Fuel Cut-off Control

During deceleration with the throttle valve closed, current to the fuel injectors is cut off to improve fuel economy at

speeds over 1,000 rpm.

Fuel cut-off action also takes place when engine speed exceeds 6,500 rpm, regardless of the position of the throttle

valve, to protect the engine from over-revving.

4. A/C Compressor Clutch Relay .

When the 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 A/C mode.

5. Evaporative Emission (EVAP) Purge Control Solenoid Valve

'96 model: When the engine coolant temperature is below 158°F (70°C), the PCM controls the EVAP purge control

solenoid valve which cuts vacuum to the EVAP purge control canister diaphragm.

'97 - 98 models: When the engine coolant temperature is above 99°F (37°C), the PCM controls the EVAP purge control

solenoid valve which controls vacuum to the EVAP purge control canister.

6. Intake Air Bypass (IAB) Low Control Solenoid Valve, Intake Air Bypass (IAB) High Control Solenoid Valve

When engine speed is below 3,350 rpm, the IAB High Control Solenoid Valve and IAB Low Control Solenoid Valve are

activated by a signal from the PCM. Intake air flows through a long chamber path, increasing torque at low RPM.

When engine speed is 3,350 - 3,950 rpm, the IAB Low Control Solenoid Valve is deactivated by the PCM. Intake air

flows through a short chamber path, increasing mid-range torque.

When the engine rpm is above 3,950 rpm, the IAB Low Control Solenoid Valve and IAB High Control Solenoid Valve are

deactivated by the PCM. This creates a very short intake path and increases high-speed torque.

7. Exhaust Gas Recirculation (EGR) Control Solenoid Valve

When the EGR is required for control of oxides of nitrogen (NOx) emissions, the PCM controls the EGR control solenoid

valve which supplies regulated vacuum to the EGR valve.

ECM Fail-safe/Back-up Functions

1. Fail-safe Function

When an abnormality occurs in a signal from a sensor, the PCM ignores that signal and assumes a pre-programmed

value for that sensor that allows the engine to continue to run.

2. Back-up Function

When an abnormality occurs in the 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 [Malfunction Indicator Lamp (MIL)]

When an abnormality occurs in a signal from a sensor, the PCM supplies ground for the MIL and stores the DTC in

erasable memory. When the ignition is initially turned on, the PCM supplies ground for the MIL for two seconds to

check the MIL bulb condition.

4. Two Driving Cycle Detection Method

To prevent false indications, the two driving cycle detection method is used for the H02S, fuel metering-related, idle

control system, ECT sensor, EGR system, TWC, EVAP control system and other self-diagnostic functions. When an

abnormality occurs, the PCM stores it in its memory. When the same abnormality recurs after the ignition switch is

turned OFF and ON (II) again, the PCM informs the driver by lighting the MIL.

However, to ease troubleshooting, this function is cancelled when you short the service check connector. The MIL will

then blink immediately when an abnormality occurs.ProCarManuals.com

A/C Service Tips and Precautions

The air
conditioner system uses
HFC-134a
(R-134a)
refrigerant
and
polyalkyleneglycol (PAG) refrigerant
oil*,
which
are not

compatible with CFC-12 (R-12) refrigerant and mineral oil. Do not use R-12 refrigerant or mineral oil in this system, and do

not attempt to use R-12 servicing equipment; damage to the air conditioner system or your servicing equipment will result.

*DENSO ND-OIL 8:

P/N 38897 - PR7 - A01AH: 120 (4 fl-oz, 4.2 Imp-oz)

P/N 38899 - PR7 - A01: 40 (1 1/3 fl-oz, 1.4 Imp-oz)

Use only service equipment that is U.L.-listed and is certified to meet the requirements of SAE J2210 to remove R-134a

from the air conditioner system.

CAUTION: Exposure to air conditioner refrigerant and lubricant vapor or mist can irritate eyes, nose and throat. Avoid

breathing the air conditioner refrigerant and lubricant vapor or mist.

If accidental system discharge occurs, ventilate work area before resuming service.

R-134a service equipment or vehicle air conditioner systems should not be pressure tested or leak tested with compressed

air.

Some mixtures of air and R-134a have been shown to be combustible at elevated pressures and can result

in tire or explosion causing injury or property damage. Never use compressed air to pressure test R-134a service equip-

ment or vehicle air conditioner systems.

Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.

1. Always disconnect the negative cable from the battery whenever replacing air conditioning parts.

2. Keep moisture and dust out of the system. When disconnecting any lines, plug or cap the fittings immediately; don't

remove the caps or plugs until just before you reconnect each line.

3. Before connecting any hose or line, apply a few drops of refrigerant oil to the O-ring.

4. When tightening or loosening a fitting, use a second wrench to support the matching fitting.

5. When discharging the system, use a R-134a refrigerant Recovery/Recycling/Charging System; don't release refriger-

ant into the atmosphere.

6. Add refrigerant oil after replacing the following parts:

NOTE:

To avoid contamination, do not return the oil to the container once dispensed, and never mix it with other refriger-

ant oils.

Immediately after using the oil, replace the cap on the container, and seal it to avoid moisture absorption.

Do not spill the refrigerant oil on the vehicle; it may damage the paint; if the refrigerant oil contacts the paint, wash

it off immediately.

Condenser ........................................ 25 (5/6 fl-oz, 0.9 Imp-oz)

Evaporator........................................ 50 (1 2/3 fl-oz, 1.8 Imp-oz)

Line or hose ...................................... 20 (2/3 fl-oz, 0.7 Imp-oz)

Receiver/Dryer
.................................
15
(1/2
fl-oz,
0.5
Imp-oz)

Leakage repair ................................. 25 (5/6 fl-oz, 0.9 Imp-oz)

Compressor ................................ For compressor replacement, subtract the volume of oil drained from the

removed compressor from 140 (4 1/3 fl-oz, 4.9 Imp-oz), and drain the calculated

volume of oil from the new compressor: 140 (4 1/3 fl-oz, 4.9 Imp-oz) — Volume

of removed compressor = Volume to drain from new compressor.

NOTE: Even if no oil is drained from the removed compressor, don't drain more

than 50 (1 2/3 fl-oz, 1.8 Imp-oz) from the new compressor.

REMOVED NEW

COMPRESSOR COMPRESSOR

SAME LEVEL

140 (4 1/3 fl-oz, 4.9 Imp-oz)
DRAINING

VOLUMEProCarManuals.com

A/C System Service

Performance Test

The performance test will help determine if the air con-

ditioner system is operating within specifications.

Use only service equipment that is U.L.-listed and is cer-

tified to meet the requirements of SAE J2210 to remove

HFC-134a (R-134a) from the air conditioner system.

CAUTION: Exposure to air conditioner refrigerant and

lubricant vapor or mist can irritate eyes, nose and

throat. Avoid breathing the air conditioner refrigerant

and lubricant vapor or mist.

If accidental system discharge occurs, ventilate work

area before resuming service.

R-134a service equipment or vehicle air conditioner sys-

tems should not be pressure tested or leak tested with

compressed air.

Some mixtures of air and R-134a have been

shown to be combustible at elevated pressures and can

result in fire or explosion causing injury or property

damage. Never use compressed air to pressure test R-

134a service equipment or vehicle air conditioner sys-

tems.

Additional health and safety information may be obtained

from the refrigerant and lubricant manufacturers.

1.

2.
Connect a R-134a refrigerant Recover/Recycling/

Charging System to the vehicle, as shown, follow-

ing the equipment manufacturer's instructions.

Insert a thermometer in the center vent outlet.

Determine the relative humidity and air tempera-

ture.
Recovery/Recycling/Charging System

HIGH-PRESSURE

SIDE

LOW-PRESSURE

SIDE

3. Test conditions:

Avoid direct sunlight.

Open hood.

Open front doors.

Set the temperature control dial on MAX COOL,

the mode control switch on VENT and the recir-

culation control switch on RECIRCULATE.

Turn the A/C switch on, and the fan switch on

MAX.

Run the engine at 1,500 rpm.

No driver or passengers in vehicle

4. After running the air conditioning for 10 minutes

under the above test conditions, read the delivery

temperature from the thermometer in the dash vent

and the high and low system pressure from the A/C

gauges.ProCarManuals.com

General Info
Specifications
Maintenance
Engine
Cooling
Fuel and Emissions
2.5L
3.2L
* Transaxle
SteeringSuspension
* Brakes (Including ABS)
* Body
* Heating, Ventilation
and Air Conditioning
* Body Electrical
* Engine Electrical
* SRS2.5L
3.2L
1995±98 TL Main Menu
As sections w/ * include SRS components, special precautions are required when servicing.
ProCarManuals.com

PGM-FI System

System Description

INPUTS
ENGINE CONTROL MODULE (ECM)

OUTPUTS

Fuel Injectors

PGM-FI Main Relay (Fuel Pump)

MIL

IAC Valve

A/C Compressor Clutch Relay

Radiator Fan Relay

Condenser Fan Relay

ALT

ICM

EVAP Purge Control Solenoid

Valve

Primary HO2S Heater

Secondary H02S Heater

EGR Control Solenoid Valve

IAB Control Solenoid Valve

EVAP Bypass Solenoid Valve*2

EVAP Control Canister Vent Shut

Valve*2

*1: '95-96 models

*2: '97 - 98 models

PGM-FI System

The PGM-FI system on this model is a sequential multiport fuel injection system.

Fuel injector Timing and Duration

The ECM contains memories for the basic discharge durations at various engine speeds and manifold air flow rates. The

basic discharge duration, after being read out from the memory, is further modified by signals sent from various sensors

to obtain the final discharge duration.

Idle Air Control

Idle Air Control Valve (IAC Valve)

When the engine is cold, the A/C compressor is on, the transmission is in gear, the brake pedal is depressed, the P/S load

is high, or the alternator is charging, the ECM controls current to the IAC Valve to maintain the correct idle speed.

Ignition Timing Control

• The ECM contains memories for basic ignition timing at various engine speeds and manifold air flow rates. Ignition

timing is also adjusted for engine coolant temperature.

• A knock control system is also used. When detonation is detected by a knock sensor (KS), the ignition timing is retarded.

Other Control Functions

1. Starting Control

When the engine is started, the ECM provides a rich mixture by increasing fuel injector duration.

2. Fuel Pump Control

• When the ignition switch is initially turned on, the ECM supplies ground to the PGM-FI main relay that supplies

current to the fuel pump for two seconds to pressurize the fuel system.

• When the engine is running, the ECM supplies ground to the PGM-FI main relay that supplies current to the fuel pump.

• When the engine is not running and the ignition is on, the ECM cuts ground to the PGM-FI main relay which cuts

current to the fuel pump.

3. Fuel Cut-off Control

• During deceleration with the throttle valve closed, current to the fuel injectors is cut off to improve fuel economy at

speeds over 1,250 rpm.

• Fuel cut-off action also takes place when engine speed exceeds 7,100 rpm, regardless of the position of the throttle

valve, to protect the engine from over-revving.
CKP/TDC/CYP Sensor

CKF Sensor

MAF Sensor

ECT Sensor

IAT Sensor

TP Sensor

EGR Valve Lift Sensor

Primary HO2S

Secondary H02S

VSS

BARO Sensor

ELD

Front KS

Rear KS

Starter Signal

ALT FR Signal

Air Conditioning Signal

A/T Gear Position Signal

Battery Voltage (IGN.1)

Brake Switch Signal

PSP Switch Signal

EVAP Purge Flow Switch*1

Fuel Tank Pressure Sensor*2ProCarManuals.com

Description

Outline

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

as shown below.

High-temperature/

high-pressure gas

Suction and compression
Radiation of heat
High-temperature/

high-pressure liquid

Traps debris,

and removes

moisture
High-temperature/

high-pressure liquid

COMPRESSOR

Less moisturized

low-pressure vapor
CONDENSER

Absorption of heat

EVAPORATOR
More liquidified

low-pressure vapor
RECEIVER/DRYER

EXPANSION VALVE

HEATER/EVAPORATOR/BLOWER
UNIT

CONDENSER
SUCTION LINE

COMPRESSOR

RECEIVER/DRYER

DISCHARGE LINE

This vehicle uses HFC-134a (R-134a) refrigerant which does not contain chlorofluorocarbons. Pay attention to the follow-

ing 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 (ND-OIL 8) designed for the R-134a compressor.

Intermixing the recommended (PAG) refrigerant oil with any other refrigerant oil will result in compressor failure.

All A/C system parts (compressor, discharge line, suction line, evaporator, condenser, receiver/dryer, expansion valve.

O-rings for joints) have to be proper for refrigerant R-134a. Do not confuse 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 System

that is U.L.-listed and is certified to meet the requirements of SAE J2210 to service R-134a air conditioning systems.

Always recover the refrigerant R-134a with an approved Recovery/Recycling/Charging System before disconnecting

any A/C fitting.
RECEIVER LINE

CONDENSER LINEProCarManuals.com

Charging System

Description

To improve fuel economy, the alternator control system within the ECM changes the voltage generated at the alternator in

accordance with driving conditions.

Throttle position (TP) sensor

Engine coolant temperature

(ECT) sensor

Intake air temperature (IAT)

sensor

TDC/CKP/CYP sensor

Vehicle speed sensor (VSS)

ELD

Air conditioning signal
ECM

Alternator

STARTER SWITCH ON
Generated voltage decreases from 14.0 V to 12.5 V

AND

ELECTRICAL LOAD below 15 A

and

VEHICLE SPEED between 9 mph (15 km/h) and

44 mph (70
km/h)

and

ENGINE SPEED between 1,100 rpm and 3,000 rpm

and

ENGINE COOLANT TEMPERATURE above 176°F

(80°C)

and

A/C SWITCH OFF

and

INTAKE AIR TEMPERATURE above 65°F (18°C)
AND

FUEL CUT-OFF CON-

TROL function is not

engaged.ProCarManuals.com