Lexus ES300 (1997 year). Service manual — part 325

S05410

Vacuum

EGR Valve

–

DIAGNOSTICS

ENGINE

DI–77

229

1997 LEXUS ES300 (RM511U)

7

Check EGR valve.

PREPARATION:
(a)

Disconnect the vacuum hose from EGR valve.

(b)

Start the engine.

CHECK:
Check whether the engine stall when apply vacuum to EGR
valve.
OK:
Engine runs rough or stall.

NG

Repair or replace EGR valve.

OK

8

Check vacuum control valve (See page

EC–7

).

NG

Replace vacuum control valve.

OK

Check and replace ECM (See page

IN–27

).

P23871

EGR Gas Temp. Sensor
Connector

DI–78

–

DIAGNOSTICS

ENGINE

230

1997 LEXUS ES300 (RM511U)

OBDII scan tool (excluding LEXUS hand–held tester)

1

Check resistance of EGR gas temp. sensor.

PREPARATION:
Disconnect the EGR gas temp. sensor connector.
CHECK:
Measure resistance between terminals of EGR gas temp. sen-
sor connector.
OK:

Resistance: 2.5 k

Ω ∼

600 k

Ω

(Not immediately after driving)

HINT:If there is open circuit, ohmmeter indicates 720 k

Ω

or

more. If there is short circuit, ohmmeter indicates 200

Ω

or less.

NG

Replace EGR gas temp. sensor.

OK

2

Check for open and short in harness and connector between EGR gas temp.
sensor and ECM (See page

IN–27

).

NG

Repair or replace harness or connector.

OK

3

Check connection and blockage of vacuum hose (See page

EC–7

).

NG

Repair or replace vacuum hose.

OK

A00481

BE6653
P23874
S02498 S02499

ON

E8

ON

OFF

EGR

Air

G

Air

E

G

E

F

F

VSV is OFF

VSV is ON

A00481

–

DIAGNOSTICS

ENGINE

DI–79

231

1997 LEXUS ES300 (RM511U)

4

Check VSV for EGR.

PREPARATION:
(a)

Remove the glove compartment (See page

SF–64

).

(b)

Disconnect the E8 connector of ECM..

(c)

Turn ignition switch ON.

CHECK:
Check VSV function.

(1)

Connect between terminal EGR of ECM and body
ground (VSV is ON).

(2)

Disconnect between terminal EGR of ECM and
body ground (VSV is OFF).

OK:

(1) VSV is ON:
Air from pipe E flows out through pipe F.
(2) VSV is OFF:
Air from pipe E flows out through pipe G.

OK

Go to step 6.

NG

5

Check operation of VSV for EGR (See page

SF–50

).

NG

Replace VSV for EGR.

OK

Check for open in harness and connector
between engine room J/B and ECM.

6

Check EGR valve (See page

EC–7

).

NG

Repair or replace EGR valve.

OK

DI–80

–

DIAGNOSTICS

ENGINE

232

1997 LEXUS ES300 (RM511U)

7

Check vacuum control valve (See page

EC–7

).

NG

Replace vacuum control valve.

OK

Check and replace ECM (See page

IN–27

).