Toyota Venza manuals

Toyota Venza: ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, the battery voltage is applied to IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contact of the engine room junction block assembly (EFI MAIN relay) and supplying power to terminals +B and +B2 of the ECM.

WIRING DIAGRAM



CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.

CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

(a) Disconnect the ECM connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

B58-104 (E1) - Body ground

Always

Below 1 Ω


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BODY GROUND)


OK

2.

INSPECT ECM (IGSW VOLTAGE)

(a) Disconnect the ECM connector.


(b) Turn the ignition switch to ON.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A49-28 (IGSW) - Body ground

Ignition switch ON

11 to 14 V

Text in Illustration

*a

Front view of wire harness connector

(to ECM)


NG

GO TO STEP 6


OK

3.

INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (EFI MAIN RELAY)

(a) Inspect the engine room junction block assembly (EFI MAIN relay) (See page ).



NG

REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY


OK

4.

CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY - ECM)

(a) Remove the engine room junction block assembly from the engine room relay block.

(b) Disconnect the engine room junction block assembly connector.

(c) Disconnect the ECM connector.

(d) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

1E-1 - A49-2 (+B)

Always

Below 1 Ω

1E-1 - A49-1 (+B2)

Always

Below 1 Ω

1F-12 - A49-6 (MREL)

Always

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

1E-1 or A49-2 (+B) - Body ground

Always

10 kΩ or higher

1E-1 or A49-1 (+B2) - Body ground

Always

10 kΩ or higher

1F-12 or A49-6 (MREL) - Body ground

Always

10 kΩ or higher


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY- ECM)


OK

5.

CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY - BODY GROUND)

(a) Remove the engine room junction block assembly from the engine room relay block.

(b) Disconnect the engine room junction block assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

1F-5 - Body ground

Always

Below 1 Ω

1F-4 - Body ground

Always

Below 1 Ω


OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY - BATTERY)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY - BODY GROUND)

6.

INSPECT RELAY (IG2 RELAY)

(a) Inspect the IG2 relay (See page ).



NG

REPLACE RELAY (IG2 RELAY)


OK

7.

CHECK HARNESS AND CONNECTOR (IG2 RELAY - ECM)

(a) Remove the IG2 relay from the engine room relay block.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

5 (IG2 relay terminal) - A49-28 (IGSW)

Always

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

5 (IG2 relay terminal) or A49-28 (IGSW) - Body ground

Always

10 kΩ or higher


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - ECM)


OK

8.

CHECK HARNESS AND CONNECTOR (IG2 RELAY POWER SOURCE)

(a) Remove the IG2 relay from the engine room relay block.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Condition

Specified Condition

3 (IG2 relay terminal) - Body ground

Always

11 to 14 V


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BATTERY)


OK

9.

CHECK HARNESS AND CONNECTOR (IG2 RELAY - BODY GROUND)

(a) Remove the IG2 relay from the engine room relay block.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

2 (IG2 relay terminal) - Body ground

Always

Below 1 Ω

Result

Proceed to

OK (w/o Smart Key System)

A

OK (w/ Smart Key System)

B

NG

C


B

GO TO STEP 12


C

REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BODY GROUND)


A

10.

CHECK HARNESS AND CONNECTOR (IG2 RELAY - IGNITION SWITCH ASSEMBLY)

(a) Remove the IG2 relay from the engine room relay block.

(b) Disconnect the ignition switch assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

1 (IG2 relay terminal) - D12-6 (IG2)

Always

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

1 (IG2 relay terminal) or D12-6 (IG2) - Body ground

Always

10 kΩ or higher


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - IGNITION SWITCH ASSEMBLY)


OK

11.

INSPECT IGNITION SWITCH ASSEMBLY

(a) Inspect the ignition switch assembly (See page ).



OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH ASSEMBLY - BATTERY)


NG

REPLACE IGNITION SWITCH ASSEMBLY

12.

CHECK HARNESS AND CONNECTOR (IG2 RELAY - POWER MANAGEMENT CONTROL ECU)

(a) Disconnect the power management control ECU connector.

(b) Remove the IG2 relay from the engine room relay block.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

1 (IG2 relay terminal) - D42-8 (IG2D)

Always

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

1 (IG2 relay terminal) - D42-8 (IG2D) - Body ground

Always

10 kΩ or higher


OK

GO TO SMART KEY SYSTEM


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - POWER MANAGEMENT CONTROL ECU)

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