Fuel Pump Control Circuit - caphector.com

In the diagram below, when the engine is cranked, current flows from terminal ST of the ignition switch to the starter relay coil and also current flows to terminal ...Missing:
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DI-141 DIAGNOSTICS

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ENGINE DI6VR-02

Fuel Pump Control Circuit CIRCUIT DESCRIPTION In the diagram below, when the engine is cranked, current flows from terminal ST of the ignition switch to the starter relay coil and also current flows to terminal STA of ECM (STA signal). When the STA signal and NE signal are input to the ECM, Tr is turned ON, current flows to coil of the circuit opening relay, the relay switches on, power is supplied to the fuel pump and the fuel pump operates. While the NE signal is generated (engine running), the ECM keeps Tr ON (circuit opening relay ON) and the fuel pump also keeps operating.

EFI Main Relay Circuit Opening Relay

Fuel Pump

EFI IG Switch ECM

IGN

FC

MAIN MAIN FL

Battery

Starter Relay Starter

AM2

Ignition Switch

ST ST

Tr

From

Park/Neutral Position Switch

Crankshaft

(NE Signal) NE

Position Sensor

(STA Signal) STA

FI7241

2002 ECHO (RM884U)

Author:

Date:

311

DI-142 DIAGNOSTICS

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ENGINE

WIRING DIAGRAM I10 Ignition Switch W-R

6

5

B-R

AM1 IG2

1O 1

1O 6 Instrument Panel J/B

Instrument Panel J/B 1A 7

ECM

1A 3 B-Y B-R

W-R 1

1 2

1

2

1 EFI

AM2 1

Instrument Panel JB 2 1

1 F6 2 MAIN

Engine Room R/B No. 1 Fusible Link Block

5

EFI Relay

1

B-L

Engine Room R/B No. 1

1

Circuit Opening Relay 9 2 1 1H

3 1 B-Y

11 1A

5

3

W-B

6 1T

F10 Fuel Pump

G

14 E4

FC

B-R

4 5

Battery EC

BG

A09141

A17562

2002 ECHO (RM884U)

Author:

Date:

312

DI-143 DIAGNOSTICS

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ENGINE

INSPECTION PROCEDURE TOYOTA hand-held tester: 1

Connect the TOYOTA hand-held tester and check operation of fuel pump (See page DI-3 ).

OK

Proceed to next circuit inspection shown on problem symptoms table (See page DI-21 ).

NG

2

Check for ECM power source circuit (See page DI-138 ).

NG

Repair or replace.

OK

3

Check circuit opening relay (Marking: CIR OPN) (See page SF-48 ).

NG

Replace circuit opening relay.

OK

2002 ECHO (RM884U)

Author:

Date:

313

DI-144 DIAGNOSTICS

4

-

ENGINE

Check voltage between terminal FC of ECM and body ground. ON

PREPARATION: (a) Remove the connector cover from the ECM. (b) Turn the ignition switch ON. CHECK: Measure voltage between terminal FC of the ECM and body ground. OK: Voltage 9 - 14 V

FC

(-)

(+) A09047

NG

Check for open in harness and connector between EFI main relay and circuit opening relay and ECM (See page IN-29 ).

OK

5

Check fuel pump (See page SF-6 ).

NG

Repair or replace fuel pump.

OK

6

Check for open in harness and connector between circuit opening relay (Marking: CIR OPN) and fuel pump and body ground (See page IN-29 ).

NG

Repair or replace harness or connector.

OK

Check and replace ECM (See page IN-29 ).

2002 ECHO (RM884U)

Author:

Date:

314

DI-145 DIAGNOSTICS

-

ENGINE

OBD II scan tool (excluding TOYOTA hand-held tester): 1

Check operation of fuel pump. ON

PREPARATION: (a) Remove the connector cover from the ECM. (b) Turn the ignition switch ON. CHECK: (a) Connect between terminal FC of the ECM connector and body ground. (b) Check for fuel pressure in the fuel inlet hose when it is pinched off. OK: There is pressure in fuel inlet hose. HINT: At this time, you will hear a fuel return flowing noise.

FC

OK Fuel Inlet Hose

BE6653 A09047 B09224

Proceed to next circuit inspection shown on problem symptoms table (See page DI-21 ).

A09116

NG

2

Check for ECM power source circuit (See page DI-138 ).

NG

Repair or replace.

OK

3

Check circuit opening relay (Marking: CIR OPN) (See page SF-48 ).

NG

Replace circuit opening relay.

OK

2002 ECHO (RM884U)

Author:

Date:

315

DI-146 DIAGNOSTICS

4

-

ENGINE

Check voltage between terminal FC of ECM and body ground (See page DI-141 ).

NG

Check for open in harness and connector between EFI main relay and circuit opening relay and ECM (See page IN-29 ).

OK

5

Check fuel pump (See page SF-6 ).

NG

Repair or replace fuel pump.

OK

6

Check for open in harness and connector between circuit opening relay (Marking: CIR OPN) and fuel pump and body ground (See page IN-29 ).

NG

Repair or replace harness or connector.

OK

Check and replace ECM (See page IN-29 ).

2002 ECHO (RM884U)

Author:

Date:

316