Lexus SC300 / Lexus SC400. Manual — part 485

ELECTRONIC CONTROL SYSTEM
Location of Electronic Control Parts

FI–84

– Electronic Control System (Location of Electronic Control Parts)

EFI SYSTEM

EFI Main Relay

INSPECTION OF EFI MAIN RELAY

1. REMOVE

EFI MAIN RELAY FROM RELAY BOX IN ENGINE

COMPARTMENT

2.

INSPECT EFI MAIN RELAY

A. Inspect relay continuity

(a) Using an ohmmeter, check that there is continuity

between terminals 1 and 3.

(b) Check that there is no continuity between terminals 2

and 4.

If continuity is not as specified, replace the relay.

B. Inspect relay operation

(a) Apply battery voltage across terminals 1 and 3.
(b) Using an ohmmeter, check that there is continuity

between terminals 2 and 4.

If operation is not as specified, replace the relay.

3.

REINSTALL EFI MAIN RELAY

FI–85

– Electronic Control System (EFI Main Relay)

EFI SYSTEM

Ignition Main Relay

INSPECTION OF IGNITION MAIN RELAY

1.

REMOVE IGNITION MAIN RELAY FROM RELAY BOX IN
ENGINE COMPARTMENT

2.

INSPECT IGNITION MAIN RELAY

A. Inspect relay continuity

(a) Using an ohmmeter, check that there is continuity

between terminals 3 and 6.

(b) Check that there is continuity between terminals 4 and

5.

(c) Check that there is no continuity between terminals 1

and 2.

If continuity is not as specified, replace the relay.

B. Inspect relay operation

(a) Apply battery voltage across terminals 3 and 6.
(b) Using an ohmmeter, check that there is continuity

between terminals 1 and 2.

(c) Apply battery voltage across terminals 4 and 5.
(d) Check that there is continuity between terminals 1 and

2.

If operation is not as specified, replace the relay.

3.

REINSTALL IGNITION MAIN RELAY

FI–86

– Electronic Control System (Ignition Main Relay)

EFI SYSTEM

Cold Start Injector Time Switch

COMPONENTS FOR REMOVAL AND
INSTALLATION

FI–87

– Electronic Control System (Cold Start Injector Time Switch)

EFI SYSTEM