Lexus SC300 / Lexus SC400. Manual — part 623

(c) Install the engine wire to the RH cylinder head with the

two bolts.

(d) Install the engine wire to the rear water by–pass joint

with the two bolts.

(e) Install the engine wire to the delivery pipes with the four

bolts.

15. REINSTALL ENGINE WIRE TO INTAKE MANIFOLD

Install the engine wire with the two bolts.

16. TEMPORARILY

REINSTALL

EGR PIPE TO RH CYLINDER

HEAD
Temporarily Install the EGR pipe with the bolt.

17. RECONNECT FUEL RETURN HOSE TO FUEL RETURN

PIPE

18. RECONNECT FUEL INLET HOSE TO LH DELIVERY PIPE

Using SST, connect the inlet hose with two new gaskets and
pulsation damper.
SST 09612–24014 (09617–24011)

Torque: 39 N

⋅

m (400 kgf

⋅

cm, 29 ft

⋅

lbf)

33 N

⋅

m (340 kgf

⋅

cm, 24 ft

⋅

lbf) for SST

HINT: Use a torque wrench with a fulcrum length of 30 cm
(11.81 in.).

FI–111

EFI SYSTEM – Electronic Control System (Knock Sensors)

19. INSTALL AIR INTAKE CHAMBER

(See steps 2 to 18 on pages

FI–35

to 41)

HINT: After the air intake chamber is installed, tighten the bolt
holding the EGR pipe to the RH cylinder head.

FI–112

EFI SYSTEM – Electronic Control System (Knock Sensors)

Main Oxygen Sensors

INSPECTION OF MAIN OXYGEN
SENSORS

1.

WARM UP ENGINE
Allow the engine to warm up to normal operating
temperature.

2.

INSPECT FEEDBACK VOLTAGE
Connect the positive (+) probe of a voltmeter to terminal VF1
(for LH bank) or VF2 (for RH bank) of the check (”DIAGNO-
SIS”) connector, and negative (–) probe to terminal E1. Per-
form the test as follows described on the next page.
HINT: Use SST when connecting between terminals TE1 and
E1 of the check connector.
SST 09843–18020

FI–113

– Electronic Control System (Main Oxygen Sensors)

EFI SYSTEM

Warm up the oxygen sensors with the engine at 2,500 rpm for
approx. 120 seconds.

Connect terminals TE1 and E1 of the check connector.
And maintain engine at 2,500 rpm.

Check the number of times the voltmeter needle fluctuates in 10 seconds.

Warm up the oxygen sensors with the engine at 2,500 rpm.
for approx. 120 seconds. And maintain engine at 2,500 rpm.

Check the number of times the voltmeter needle
fluctuates in 10 seconds.

Disconnect terminals TE1 and E1 of the check connector.
And maintain engine at 2,500 rpm.

Measure voltage between terminals VF1 (VF2) and E1.

Replace the ECU.

Normal

Measure voltage between terminals VF1 (VF2) and E1.

Read and record diagnostic codes. (See TR Section)

Disconnect terminals TE1 and E1 of the check connector.
And maintain engine at 2,500 rpm.

Repair the relevant diagnostic code.

Repair the relevant diagnostic code.

Normal code, code Nos.
21, 25 and 26

Malfunction code(s)
(Ex. code Nos. 21, 25 and 26)

Malfunction code(s)
(Ex. code Nos. 21, 25 and 26)

Normal code, code Nos.
21, 25 and 26

More than 0 V

0 V

Less than 8 times

Less than 8 times

8 times or more

8 times
or more

Zero

Zero

Zero again

After replacing
the oxygen sensor

CONTINUED ON PAGE

FI–115

FI–114

EFI SYSTEM – Electronic Control System (Main Oxygen Sensors)