1996 ACURA RL KA9 fuel filter

Fuel Supply System

The HDS or the scan tool indicates Diagnostic Trouble Code (DTC) P0171: The fuel system is too lean [Right

Bank (Bank 1)].

The HDS or the scan tool indicates Diagnostic Trouble Code (DTC) P0172: The fuel system is too rich [Right

Bank (Bank 1)].

The HDS or the scan tool indicates Diagnostic Trouble Code (DTC) P0174: The fuel system is too lean [Left Bank

(Bank 2)].

The HDS or the scan tool indicates Diagnostic Trouble Code (DTC) P0175: The fuel system is too rich [Left Bank

(Bank 2)].

Description

By monitoring the Long Term Fuel Trim, long term malfunctions in the fuel system will be detected.

If a
malfunction
has
been detected
during
two
consecutive
trips,
the MIL
will
come
on and DTC
P0171,
P0172, P0174

and/or P0175 will be stored.

NOTE: If some of the DTCs listed below are stored at the same time as DTC P0171, P0172, P0174 and/or P0175, trou-

bleshoot those DTCs first, then troubleshoot DTC P0171, P0172, P0174 and/or P0175.

P0107, P0108, P1128, P1129: MAP Sensor

P0135: Right Primary HO2S Heater (Bank 1, Sensor 1)

P0137, P0138: Secondary HO2S (Sensor 2)

P0141: Secondary HO2S Heater (Sensor 2)

P0155: Left Primary H02S Heater (Bank 2, Sensor 1)

P0401: EGR Flow Insufficient

P0404: EGR Valve Lift Insufficient

P0406: EGR Valve Position Sensor High Voltage

Possible Cause

Fuel Pump insufficient flow/pressure

Fuel Feed Line clogged, leaking

Fuel Pressure Regulator stuck open

Fuel Filter clogged

Injector clogged, air inclusion

Gasoline doesn't meet Owner's Manual spec.

Primary H02S (Sensor 1) deteriorated

EGR System insufficient flow

Exhaust leak

Fuel Pressure Regulator clogged, stuck closed

Fuel Return Pipe clogged

Injector leaking

Gasoline doesn't meet Owner's Manual spec.

Primary HO2S (Sensor 1) deteriorated

EGR System malfunction (too much flow)

EVAP Canister Purge Valve leaking, stuck opened

(cont'd)ProCarManuals.com

PGM-FI System

Fuel Supply System (cont'd)

Troubleshooting Flowchart

— The MIL has been reported on.

— DTC P0171, P0172, P0174 and/

or P0175 are stored.

Check the fuel pressure.

Is the fuel pressure OK?
NO

YES

Check the Primary HO2S:

1. Start the engine. Hold the

engine at 3,000 rpm with no

load (in Park or neutral) until

the radiator fan comes on.

2. Check the right primary or left

primary* H02S (Sensor 1) out-

put voltage with the HDS or

the scan tool.
Is the fuel pressure too high

or too low?
Check the fuel pressure regulator

and fuel return pipe.

LOW

Check the fuel pump, fuel feed

pipe, fuel filter, and fuel pressure

regulator.

Does it stay at less than 0.3 V

or more than 0.6V?
Replace the HO2S.

NO

Check for a sticking or leaking

EVAP canister purge valve:

With a vacuum pump, apply vacu-

um to the EVAP canister purge

valve from the intake manifold

side.

Does it hold vacuum?
Replace the EVAP canister purge

valve.

YES

Check the EGR system. If it is OK,

replace the fuel injectors.

*: P0174 or P0175ProCarManuals.com

Component Location s
Index (cont'd )
FUEL TAN KReplacement , pag e 11-15 1
FUEL TAN K VAPO RCONTROL VALVETesting, pag e 11-20 1
FUEL FILTE R
Replacement , pag e 11-14 2
FUE L PRESSUR E
REGULATO R
Testing, pag e 11-13 5Removal , pag e 11-13 6Reassembly , pag e 11-13 6
FUEL PULSATIO N
DAMPE R
FUE L RAI L
INJECTOR S
Replacement , pag e 11-13 3
EVAPORATIV E EMISSIO N
(EVAP)CANISTE R PURG E
VALV E FUE
L GAUG E SENDIN G UNI T
Testing , pag e 11-14 4
FUE L PUM P
Testing , pag e 11-14 2
Replacement , pag e 11-14 3
FUE L FIL L
CAP
EVAPORATIV EEMISSION(EVAP)CANISTE RFILTER
FUEL TUBE/QUICK-CONNEC TFITTINGSPrecautions , pag e 11-12 9
Disconnection , pag e 11-12 9
Connection , pag e 11-13 0
EVAPORATIV E EMISSIO N
(EVAP ) CANISTE R
VEN T SHU T VALV E
Replacement , pag e 11-20 1
FUE L VAPO R PIP E
EVAPORATIV E EMISSIO N
(EVAP ) TW O WA Y VALV E
Testing , pag e 11-20 5
FUE L TAN K PRESSUR E (FTP )
SENSO R
FUE L RETUR N PIP E EVAPORATIV
E EMISSIO N
(EVAP ) BYPAS S SOLENOI D
VALV E
Replacement , pag e 11-20 2
EVAPORATIV E EMISSIO N
(EVAP ) CANISTE R
Troubleshooting , pag e 11-19 6
FUE
L FEE D PIP E
'00 - 0 4 models :
For Troubleshooting of DTC related components, see chart on page 11-53 ('00-'03 models) 11-41 ('04 model).
ProCarManuals.com

'00 - 01 models:

Vacuum hose No.

LEFT PRIMARY HEATED OXYGEN SENSOR (LEFT PRIMARY

HO2S) (BANK 2, SENSOR 1)

RIGHT PRIMARY HEATED OXYGEN SENSOR (RIGHT
PRIMARY
HO2S) (BANK
1,
SENSOR
1)

SECONDARY HEATED OXYGEN SENSOR (SECONDARY

HO2S) (SENSOR 2)

MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR

INTAKE AIR TEMPERATURE (IAT) SENSOR

LEFT KNOCK SENSOR (BANK 2)

RIGHT KNOCK SENSOR (BANK 1)

IDLE AIR CONTROL (IAC) VALVE

IDLE AIR CONTROL (IAC) THERMAL VALVE

THROTTLE BODY

IDLE ADJUSTING SCREW

INJECTOR

FUEL PULSATION DAMPER

FUEL FILTER

FUEL PRESSURE REGULATOR

PRESSURE REGULATOR VACUUM CONTROL SOLENOID

VALVE

FUEL PUMP

FUEL TANK

FUEL TANK VAPOR CONTROL VALVE

FUEL TANK VAPOR RECIRCULATION VALVE

AIR CLEANER

RESONATOR

INTAKE MANIFOLD RUNNER CONTROL (IMRC) CHECK

VALVE
INTAKE MANIFOLD RUNNER CONTROL (IMRC) VACUUM

RESERVOIR

INTAKE MANIFOLD RUNNER CONTROL (IMRC) SOLENOID

VALVE 1

INTAKE MANIFOLD RUNNER CONTROL (IMRC)

DIAPHRAGM 1

INTAKE MANIFOLD RUNNER CONTROL (IMRC) SOLENOID

VALVE 2

INTAKE MANIFOLD RUNNER CONTROL (IMRC)

DIAPHRAGM 2

EXHAUST GAS RECIRCULATION (EGR) VALVE VACUUM

CONTROL VALVE

EXHAUST GAS RECIRCULATION (EGR) VALVE VACUUM

CONTROL SOLENOID VALVE

EXHAUST GAS RECIRCULATION (EGR) VALVE and POSI-

TION SENSOR

POSITIVE CRANKCASE VENTILATION (PCV) VALVE

EVAPORATIVE EMISSION (EVAP) CANISTER PURGE VALVE

EVAPORATIVE EMISSION (EVAP) CANISTER

EVAPORATIVE EMISSION (EVAP) CANISTER VENT SHUT

VALVE

EVAPORATIVE EMISSION (EVAP) CANISTER FILTER

EVAPORATIVE EMISSION (EVAP) TWO WAY VALVE

EVAPORATIVE EMISSION (EVAP) BYPASS SOLENOID

VALVE

FUEL TANK PRESSURE (FTP) SENSOR

THREE WAY CATALYTIC CONVERTER (TWC)

ENGINE MOUNT CONTROL SOLENOID VALVEProCarManuals.com

Fuel Supply System

Description

By monitoring the Long Term Fuel Trim, long term malfunctions in the fuel system will be detected.

If a
malfunction
has
been detected during
two
consecutive
trips,
the MIL
will
come
on and DTC
P0171, P0172,
P0174

and/or P0175 will be stored.

NOTE: If some of the DTCs listed below are stored at the same time as DTC P0171, P0172, P0174 and/or P0175, trou-

bleshoot those DTCs first, then troubleshoot DTC P0171, P0172, P0174 and/or P0175.

P0106*1, P0107, P0108, P1128*2, P1129*2: MAP Sensor

P0135: Right Primary HO2S Heater (Bank 1, Sensor 1)

P0137, P0138: Secondary HO2S (Sensor 2)

P0141: Secondary HO2S Heater (Sensor 2)

P0155: Left Primary HO2S Heater (Bank 2, Sensor 1)

P0401: EGR Flow Insufficient

P1491: EGR Valve Lift Insufficient

P1498: EGR Valve Position Sensor High Voltage

*1: '96 model only

*2: '97 - 01 models

DTC P0172, P0175

System too rich
• Fuel Pump insufficient flow/pressure

• Fuel Feed Line clogged, leaking

• Fuel Pressure Regulator stuck open

• Fuel Filter clogged

• Injector clogged, air inclusion

• Gasoline doesn't meet Owner's Manual spec.

• Primary HO2S (Sensor 1) deteriorated

• MAP Sensor range/performance*1

• EGR System insufficient flow

• Exhaust leak

• Fuel Pressure Regulator clogged, stuck closed

• Fuel Return Pipe clogged

• Injector leaking

• Gasoline doesn't meet Owner's Manual spec.

• Primary HO2S (Sensor 1) deteriorated

• MAP Sensor range/performance*1

• EGR System malfunction (too much flow)

• EVAP Canister Purge Valve leaking, stuck opened
DTCP0171, P0174

System too lean
The scan tool indicates Diagnostic Trouble Code (DTC) P0171: The fuel system is too lean [Right Bank (Bank 1)].

The scan tool indicates Diagnostic Trouble Code (DTC) P0172: The fuel system is too rich [Right Bank (Bank 1)].

The scan tool indicates Diagnostic Trouble Code (DTC) P0174: The fuel system is too lean [Left Bank (Bank 2)].

The scan tool indicates Diagnostic Trouble Code (DTC) P0175: The fuel system is too rich [Left Bank (Bank 2)].

Possible CauseProCarManuals.com

PGM-FI System

Fuel Supply System (cont'd)

— The MIL has been reported on.

— DTC P0171, P0172, P0174 and/

or P0175 are stored.

Check the fuel pressure.

Is the fuel pressure OK?
NO

YES

Check the Primary HO2S:

1. Start the engine. Hold the

engine at 3,000 rpm with no

load (in Park or neutral) until

the radiator fan comes on.

2. Check the right primary or left

primary* HO2S (Sensor 1) out-

put with the scan tool.
Is the fuel pressure too high

or too low?
Check the fuel pressure regulator

and fuel return pipe.

LOW

Check the fuel pump, fuel feed

pipe, fuel filter, and fuel pressure

regulator.

Does it stay at less than 0.3 V

or more than 0.6 V?
Replace the HO2S.

NO

Check for a sticking or leaking

EVAP canister purge valve:

With a vacuum pump, apply vacu-

um to the EVAP canister purge

valve from the intake manifold

side.

Does it hold vacuum?

('96 model only)
Replace the EVAP canister purge

valve.

YES

Check the MAP sensor output:

1. Turn the ignition switch ON (II).

2. Check the MAP with the scan

tool.

Does it indicate atmospheric

pressure?
YES

*: P0174 or P0175
Check the response of the MAP

sensor:

1. Start the engine.

2. Check the MAP with the scan

tool.

Is a MAP of 40.0 kPa (300 mmHg,

12.0 inHg) or less indicated within

one second after starting the

engine?
Replace the MAP sensor.

YES

Check the EGR system. If it is OK,

replace the fuel injectors.
NO
NO

Replace the MAP sensor.
NO
YES
HIGH
Troubleshooting FlowchartProCarManuals.com

Fuel Supply System

Fuel Lines

Check fuel system lines, hoses, fuel filter, and other components for damage, leaks or deterioration, and replace if neces-

sary.

'96 - 99 models:

22 N-m

(2.2 kgf-m, 16 Ibf-ft)
22 N-m

(2.2 kgf-m,

16 Ibf-ft)

'00 - 01 models:
37 N-m

(3.8 kgf-m, 27 Ibf-ft)

22 N-m

(2.2 kgf-m, 16 Ibf-ft)
22 N-m

(2.2 kgf-m

16 Ibf-ft)

37 N-m

(3.8 kgf-m, 27 Ibf-ft)ProCarManuals.com

'96 - 99 models:

Check all hose clamps and retighten if necessary.

EVAPORATIVE EMISSION

(EVAP) TWO WAY VALVE

EVAPORATIVE EMISSION

(EVAP) CONTROL

CANISTER

10 -
15
mm

(0.39
-
0.59
in)
Clamp in the middle.
Clamp in the middle.
FUEL

TANK
FUEL

FILTER
To

FUEL

PRESSURE

REGULATOR
BASE

GASKET

Replace.
BASE GASKET

Replace.
FUEL PUMP

ASSEMBLY
FUEL GAUGE SENDING

UNIT ASSEMBLY

FUEL TANK EVAPORATIVE

EMISSION (EVAP)

VALVEProCarManuals.com