Lexus SC300 / Lexus SC400. Service manual — part 482

INSPECTION OF SUB–OXYGEN SENSOR

1.

INSPECT SUB–OXYGEN SENSOR
(a) Cancel diagnostic code. (See TR section)
(b) Allow the engine to warm up to normal operating

temperature.

(c) Drive for 5 minutes or more between 80km/h (50 mph)

and 100 km/h (62 mph) in ”D” range.

(d) Following the conditions in step (c), press fully on the

accelerator pedal for 2 seconds or more.

HINT: Do not exceed 100 km/h (62 mph), or diagnostic code
will be cancelled.
(e) Stop the vehicle, and turn the ignition switch to OFF.
(f) Carry

out steps (b), (c) and (d) again to test acceleration.

If code No. 27 reappears again, check the sub–oxygen sen-
sor circuit. If the circuit is normal, replace the sub–oxygen
sensor.

2.

DISCONNECT CABLE FROM NEGATIVE TERMINAL OF
BATTERY
CAUTION: Turn the ignition switch to ”LOCK”. Discon-
nect the cable from the negative (–) terminal of the bat-
tery. Wait at least 20 seconds before proceeding with
work.

3.

REMOVE TRANSMISSION SHIFT LEVER KNOB
(A/T)
(a) Push down the lever cover.

(b) Remove the two screws and shift lever knob.
(c) Remove the lever cover.

–

EFI SYSTEM

FI–77

Electronic Control System (Sub–Oxygen Sensor (USA Spec. only))

4. (A/T)
REMOVE CUP HOLDER

Using a screwdriver, pry out the rear side of the cup holder.
Remove the cup holder.

5.

REMOVE UPPER REAR CONSOLE PANEL
Using a screwdriver, pry out the console panel.

6. (A/T)
REMOVE UPPER CONSOLE PANEL

(a) Remove the six mounting screws.
(b) Using a screwdriver, pry out the console panel.

7.

DISCONNECT SUB–OXYGEN SENSOR CONNECTOR

8. INSPECT

HEATER

RESISTANCE OF SUB–OXYGEN

SENSOR
Using an ohmmeter, measure the resistance between the ter-
minals +B and HT.

Resistance: 5.1–6.3

at 20

°

C (68

°

F)

FI–78

–

EFI SYSTEM

Electronic Control System (Sub–Oxygen Sensor (USA Spec. only))

If the resistance is not as specified, replace the sensor as fol-
lows:

•

Disconnect the grommet from the floor panel, and pull
out the wire of the sub–oxygen sensor from the floor
panel.

•

Remove the two nuts, cover and sub–oxygen sensor
from the front exhaust pipe.

•

Install a new gasket, a new sub–oxygen sensor and the
cover to the front exhaust pipe with the two nuts.

Torque: 18 N

⋅

m (180 kgf

⋅

cm, 13 ft

⋅

lbf)

•

Run the wire of the sub–oxygen sensor through the hole
in the floor panel.

9.

RECONNECT SUB–OXYGEN SENSOR CONNECTOR

10. (A/T)

REINSTALL UPPER REAR CONSOLE PANEL
(a) Fit the console panel to the console box with five clips.
(b) Install the console panel with the six screws.

11. REINSTALL UPPER CONSOLE PANEL

Fit the console panel to the console box with the four clips.

12. (A/T)

REINSTALL CUP HOLDER
Fit the cup holder to the console box.

–

EFI SYSTEM

FI–79

Electronic Control System (Sub–Oxygen Sensor (USA Spec. only))

13. REINSTALL TRANSMISSION SHIFT LEVER KNOB

(A/T)
(a) Slide the lever cover on the lever shaft.

(b) Install the shift lever knob with the two screws.

(c) Attach the lever cover to the lower side of the lever knob.

14. RECONNECT CABLE TO NEGATIVE TERMINAL OF BAT-

TERY

FI–80

–

EFI SYSTEM

Electronic Control System (Sub–Oxygen Sensor (USA Spec. only))