Toyota Venza: ECU Power Source Circuit

Toyota Venza Service Manual / U660e Automatic Transmission / Transaxle / Automatic Transaxle System / ECU Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, voltage from the ECM's MREL terminal is applied to the EFI MAIN relay. This causes the contacts of the EFI MAIN relay to close, which supplies power to terminal +B of the TCM.

WIRING DIAGRAM

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (TCM - BODY GROUND)

(a) Turn the ignition switch off.

(b) Disconnect the TCM connectors.

Standard Resistance:

Tester Connection	Condition	Specified Condition
B40-8 (E1) - Body ground	Always	Below 1 Ω

Text in Illustration

*1	Front view of wire harness connector (to TCM)

REPAIR OR REPLACE HARNESS OR CONNECTOR

2.	INSPECT ECU TERMINAL VOLTAGE (+B TERMINAL)

(a) Disconnect the TCM connectors.

(b) Turn the ignition switch to ON.

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
B40-18 (+B) - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

*1	Front view of wire harness connector (to TCM)

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

3.	CHECK HARNESS AND CONNECTOR (TCM - ENGINE ROOM JUNCTION BLOCK ASSEMBLY)

(a) Turn the ignition switch off.

(b) Disconnect the TCM connector.

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

Standard Resistance (Check for Open):

Tester Connection	Condition	Specified Condition
B40-18 (+B) - 1F-18 (+B)	Always	Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection	Condition	Specified Condition
B40-18 (+B) or 1F-18 (+B) - Body ground	Always	10 kΩ or higher

Text in Illustration

Engine Room Junction Block Assembly

Front view of wire harness connector

(to Engine Room Junction Block Assembly)

Front view of wire harness connector

(to TCM)

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
1F-9 - 1F-18	Always	Below 1 Ω

Text in Illustration

*1	Component without harness connected (Engine Room Junction Block Assembly)

GO TO ECM POWER SOURCE CIRCUIT (ENGINE CONTROL SYSTEM / SFI SYSTEM)

REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY

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