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Acura RL (1996-2004 year). Manual - part 372

11-106

11-182

*2: These DTCs require two "trips" or two driving cycles unless the SCS service connector is connected.
*5: The indicator light and the Malfunction Indicator Lamp (MIL) may come on simultaneously.
*6: with TCS, VSA

11-187
('00-03)

('96-99)

11-192

11-196
('00-03)

('96-99)

Main Menu

Table of Contents

Troubleshooting

How to Read Flowcharts

A flowchart is designed to be used from start to final repair. It's like a map showing you the shortest distance. But beware:

if you go off the "map" anywhere but a "stop" symbol, you can easily get lost.

Describes the conditions or situation to start a troubleshooting flowchart.

Asks you to do something; perform a test, set up a condition etc.

Asks you about the result of an action, then sends you in the appropriate troubleshooting direction.

(bold type)

The end of a series of actions and decisions, describes a final repair action and sometimes directs you to

an earlier part of the flowchart to confirm your repair.

NOTE:
• The term "Intermittent Failure" is used in these charts. It simply means a system may have had a failure, but it checks

out OK at this time. If the Malfunction Indicator Lamp (MIL) on the dash does not come on, check for poor connections
or loose wires at all connectors related to the circuit that you are troubleshooting (see illustration below).

• Most of the troubleshooting flowcharts have you reset the Powertrain Control Module (PCM) and try to duplicate the

Diagnostic Trouble Code (DTC). If the problem is intermittent and you can't duplicate the code, do not continue through

the flowchart. To do so will only result in confusion and, possibly, a needlessly replaced PCM.

• "Open" and "Short" are common electrical terms. An open is a break in a wire or at a connection. A short is an acci-

dental connection of a wire to ground or to another wire. In simple electronics, this usually means something won't
work at all. In complex electronics (like PCM's), this can sometimes mean something works, but not the way it's sup-
posed to.

TIGHT

LOOSE

(bold type)

Main Menu

Table of Contents

PGM-FI System

System Description

INPUTS

POWERTRAIN CONTROL MODULE (PCM)

OUTPUTS

CKP/CYP Sensor

Cruise

Control

Signal ('04)

MAP Sensor
ECT Sensor
IAT Sensor

TP Sensor

EGR Valve Position Sensor
Left Primary HO2S
Right Primary HO2S

Secondary HO2S

VSS

BARO Sensor
Left Knock Sensor
Right Knock Sensor

TCS Signals*
VSA Signals*

Spark Plug Voltage Detection

Module Signal

Starter Signal

ALT FR Signal
Air Conditioning Signal
Transmission Range Switch Signal

Battery Voltage (IGN.1)
Brake Pedal Position Switch Signal
PSP Switch Signal
Immobilizer Signal
FTP Sensor
Countershaft Speed Sensor
Mainshaft Speed Sensor

Idle Air Injector Timing and Duration

Other Control Functions

Ignition Timing Control

PCM Back-up Functions

Injectors
PGM-FI Main Relay (Fuel Pump)
Fuel Pump Relay
MIL
D4 Indicator Light
IAC Valve

A/C Compressor Clutch Relay

ICM
EVAP Canister Purge Valve
Left Primary HO2S Heater
Right Primary HO2S Heater
Secondary HO2S Heater
EGR Valve Vacuum Control Valve
Pressure Regulator Vacuum

Control Solenoid Valve

IMRC Solenoid Valve 1
IMRC Solenoid Valve 2
DLC

Torque Converter Clutch Solenoid

Valve

Shift Solenoid Valve
A/T Clutch Pressure Control

Solenoid Valve

EVAP Bypass Solenoid Valve
EVAP Canister Vent Shut Valve
Engine Mount Control Solenoid

Valve

PGM-FI System

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

Injector Timing and Duration

The PCM contains memories for the basic discharge durations at various engine speeds and manifold pressures. 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 power
steering load is high, or the alternator is charging, the PCM controls current to the IAC Valve to maintain the correct idle
speed.

Ignition Timing Control
• The PCM 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, the ignition timing is retarded.

Other Control Functions

1. Starting Control

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

2. Fuel Pump Control

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

rent to the fuel pump for 2 seconds to pressurize the fuel system.

• When the engine is running, the PCM 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 PCM cuts ground to the PGM-FI main relay which cuts

current to the fuel pump.

*: with TCS

*1: with VSA

Idle Air Control

Coolant Temperature Gauge ('04)

Main Menu

Table of Contents

PGM-FI System

System Description (cont'd)

3. Fuel Cut-off Control

• During deceleration with the throttle valve closed, current to the 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 5,900 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) Control.

When the engine coolant temperature is above 99°F (37°C): '96 - 99 models, 140°F (60°C): '00 - 04 models, the PCM
controls the EVAP canister purge valve which controls vacuum to the EVAP canister.

6. Intake Manifold Runner Control (IMRC)

When engine speed is below 3,200 rpm, the IMRC Solenoid Valve 1 and IMRC Solenoid Valve 2 are activated by a sig-

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

When engine speed is 3,200 - 3,800 rpm, the IMRC 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 3,800 rpm, the IMRC Solenoid Valve 1 and IMRC Solenoid Valve 2 are deactivated by the

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

7. Exhaust Gas Recirculation (EGR) Control

When the EGR is required for control of oxides of nitrogen (NOx) emissions, the PCM controls the EGR control valve
vacuum 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 2 seconds to check
the MIL bulb condition.

4. Two Trip Detection Method ('96 - 97 models)

To prevent false indications, the Two Trip Detection Method is used for the HO2S, fuel metering-related, idle control
system, ECT sensor, EGR system self-diagnostic functions and EVAP control system. 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.

5. Two Driving Cycle Detection Method ('96 - 97 models)

A "Driving Cycle" consists of starting the engine, beginning closed loop operation, and stopping the engine. If misfir-

ing that increases emissions, EVAP control system malfunction or TWC deterioration is detected during two consecu-

tive driving cycles, the PCM turns the MIL on.

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.

6. Two Driving Cycle Detection Method ('98 - 04 models)

To prevent false indications, the "two driving cycle detection method" is used for the HO2S, fuel metering-related, idle

control system, ECT sensor, EGR system, TWC and 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 switch is turned OFF and
ON (II) again, the PCM informs the driver by turning on the MIL.

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Content .. 370 371 372 373 ..