Acura RL (1996-2004 year). Manual - part 401

Intermittent failure, system is OK
at this time. Check for poor con-
nections or loose wires at C251,
C254 (located at left shock tower),
C107 (EGR valve) and PCM.

VACUUM PUMP/GAUGE, 0 - 30 in.Hg

A973X - 041 - XXXXX

No. 11 VACUUM
HOSE

(To page

EGR
VALVE

Problem verification:

1. Do the PCM Reset Procedure.

2. Connect the SCS service con-

nector.

3. Start the engine. Hold the

engine at 3,000 rpm with no
load (in Park or neutral) until
the radiator fan comes on.

4. Drive the vehicle on the road for

approx. 10 minutes. Try to keep

the engine speed in the 1,700 -

2,500 rpm range.

The MIL has been reported on.

DTC P1491 is stored.

Main Menu

Table of Contents

(From page

11-168

Is there any vacuum?

Check for a short in the wire (ES
line):

1. Turn the ignition switch OFF.

2. Disconnect the PCM connec-

tor A (26P).

3. Check for continuity between

body ground and the control
box 4P connector terminal No. 2.

Is there continuity?

Substitute a known-good PCM
and recheck (see page

11-42

for

immobilizer information). If symp-

tom/indication goes away, re-
place the original PCM.

(From page

11-168

Check for a malfunction in the
EGR valve:

1. Move the vacuum pump/gauge

to the EGR valve.

2. With the engine at idle, apply

26.7 kPa (200 mmHg, 8.0 in.Hg)
of vacuum to the EGR valve.

Does the engine stall or run
rough and does the EGR valve
hold vacuum?

YES

Check for an open in the wire

(VCC2 line):
1. Turn the ignition switch OFF.
2. Disconnect the EGR valve

position sensor 3P connector.

3. Turn the ignition switch ON (II).
4. Measure voltage between the

EGR valve position sensor 3P
connector terminals No. 1 and
No. 3.

Is there approx. 5 V?

(To page

Check vacuum hose routing of
the entire EGR system. If hose
routing is OK, replace the EGR
valve vacuum control solenoid
valve.

CONTROL BOX 4P CONNECTOR (C257)

Wire side of female terminals

Repair short in the wire between
PCM (A6) and EGR valve vacuum
control solenoid valve.

VACUUM
PUMP/GAUGE,
0 - 30 in.Hg

A973X - 041 -
XXXXX

Replace the EGR valve.

EGR
VALVE

No. 11
VACUUM
HOSE

EGR VALVE POSITION SENSOR CONNECTOR (C107)

Wire side of female terminals

YES

(To page

YES

Main Menu

Table of Contents

Emission Control System

Exhaust Gas Recirculation (EGR) System (cont'd)

(From page

PCM CONNECTOR D (22P)

Check for an open in the wire
(VCC2 line):
Measure voltage between the
PCM connector terminals D21
and D22.

Is there approx. 5 V?

Substitute a known-good PCM
and recheck (see page

11-42

for

immobilizer information). If
symptom/indication goes away,
replace the original PCM.

Repair open in the wire between
the EGR valve and PCM (D21).

(From page

Check for an open or short in the
EGR valve position sensor:

1. Turn the ignition switch OFF.

2. At the sensor side, measure

resistance between the EGR
valve position sensor 3P connec-

tor terminals No. 1 and No. 2.

Is there continuity or resis-

tance of 100 k or higher?

Check for an open or short in the
EGR valve position sensor.

Measure resistance between the

EGR valve position sensor 3P con-
nector terminals No. 2 and No. 3.

Is there 100 Kfi or higher?

YES

Check for an open or short in the
wire (EGRL line):

1. Reconnect the EGR valve

position sensor 3P connector.

2. Turn the ignition switch ON (II).
3. Measure voltage between the

PCM connector terminals D17
and D22.

Is there approx. 1.2 V?

(To page

11-171

EGR VALVE POSITION SENSOR CONNECTOR

Replace the EGR valve.

Terminal side of male terminal

Replace the EGR valve.

PCM CONNECTOR D (22P)

YES

Wire side of female terminals

(To page

11-171

YES

Wire side of female terminals

Main Menu

Table of Contents

(From page

PCM CONNECTOR D (22P)

Check for a short in the wire
(EGRL line):
Check for continuity between
PCM connector terminal D17 and
the body ground.

Is there continuity?

Repair open in the wire between

the EGR valve and the PCM (D17).

YES

Repair short in the wire between

the EGR valve and PCM (D17).

(From page

Check for an open in the wire (IG1
line):

1. Turn the ignition switch OFF.

2. Disconnect the control box

connector.

3. Turn the ignition switch ON (II).
4. Measure voltage between body

ground and the control box
connector terminal No. 1.

Wire side of female terminals

CONTROL BOX 4P CONNECTOR (C257)

Wire side of female terminals

Is there battery voltage?

YES

Check the vacuum routing:

1. Reconnect the vacuum pump/

gauge to the No. 11 hose.

2. Start the engine and let it idle.
3. At the control box side, con-

nect the battery positive ter-
minal to the EGR valve vacu-
um control solenoid valve
connector terminal No. 1.

4. While watching the vacuum

gauge, connect the battery neg-
ative terminal to the EGR valve
vacuum control solenoid
valve connector terminal No. 2.

Repair open in the wire between

the EGR valve vacuum control

solenoid valve and No. 20 ECU
(PCM) (20 A) fuse in the under-
dash fuse/relay box.

CONTROL BOX 4P
CONNECTOR

Is there approx. 26.7 kPa
(200 mmHg, 8.0 in.Hg) of vacu-

um within 1 second?

Terminal side
of male terminals

YES

Check the vacuum hoses:

1. Turn the ignition switch OFF.

2. Inspect the No. 11 and No. 3

hoses for leaks, restrictions or
misrouting.

Are the hoses OK?

(To page

11-172