Lexus SC300 / Lexus SC400. Service manual — part 484

Fuel Pump ECU

COMPONENTS FOR REMOVAL AND
INSTALLATION

–

EFI SYSTEM

Electronic Control System (Fuel pump ECU)

FI–81

INSPECTION OF FUEL PUMP ECU

1.

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.

2.

REMOVE SEAT CUSHION AND BACK

3.

REMOVE QUARTER TRIM
(a) Disconnect the rear side of the scuff plate by pulling it.

(b) Remove clip A.
(c) Remove the belt hole cover by pulling it.

(d) Remove clip B.
(e) Remove the quarter trim by pulling it.

4.

DISCONNECT FUEL PUMP ECU CONNECTOR

FI–82

–

EFI SYSTEM

Electronic Control System (Fuel pump ECU)

5.

INSPECT FUEL PUMP ECU
(a) Connect the cable to the negative (–) terminal of the

battery.

(b) Check the connector on the wiring harness side as

shown in the chart.

Check for

Tester connection

Condition

Specified value

Continuity

E–Ground

–

Continuity

Continuity

DI–Ground

–

Continuity

Voltage

FP Ground

Sudden racing

12–14 V

Voltage

FP–Ground

Idling

8–10 V

Voltage

+B–Ground

IG SW ON

8–16 V

Voltage

FPC–Ground

Sudden racing

(6,000 rpm or more)

4–6 V

Voltage

FPC Ground

Idling

2.5 V

If circuit is as specified, replace the fuel pump ECU.
(c) Disconnect the cable from the negative (–) terminal of

the battery.

6.

RECONNECT FUEL PUMP ECU CONNECTOR

7.

INSTALL QUARTER TRIM
(a) Attach the upper side of the quarter trim to the quarter

panel.

(b) Install the quarter trim with the four clips.

–

EFI SYSTEM

Electronic Control System (Fuel pump ECU)

FI–83

(c) Install the belt hole cover with the two clips.

(d) Install the rear side of the scuff.

8.

REINSTALL SEAT BACK AND CUSHION

9.

RECONNECT CABLE FROM NEGATIVE TERMINAL OF
BATTERY

FI–84

–

EFI SYSTEM

Electronic Control System (Fuel pump ECU)