AUTOMATIC TRANSAXLE SYSTEM ECU Power Source Circuit

DTC Code	DTC Name
	ECU Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, voltage from the MREL terminal of the ECM is applied to the EFI-MAIN NO. 1 relay. This causes the contacts of the EFI-MAIN NO. 1 relay to close, which supplies power to terminal +B of the TCM.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

Note:

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

PROCEDURE

CHECK HARNESS AND CONNECTOR (TCM - BODY GROUND)

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

Disconnect the TCM connector.

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

Standard Resistance


Tester Connection	Condition	Specified Condition
B79-8 (E1) - Body ground	Always	Below 1 Ω

Result


Proceed to
OK
NG

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

INSPECT ECU TERMINAL VOLTAGE (+B TERMINAL)

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

Disconnect the TCM connector.

Turn the ignition switch to ON.

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

Standard Voltage


Tester Connection	Switch Condition	Specified Condition
B79-18 (+B) - Body ground	Ignition switch ON	11 to 14 V

Result


Proceed to
OK
NG

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

Click here Click here

NG

CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 1 RELAY - TCM)

Remove the EFI-MAIN NO. 1 relay from the engine room relay block and junction block assembly.
Disconnect the B79 TCM connector.

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

Standard Resistance


Tester Connection	Condition	Specified Condition
3 (EFI-MAIN NO. 1 relay) - B79-18 (+B)	Always	Below 1 Ω
3 (EFI-MAIN NO. 1 relay) or B79-18 (+B) - Body ground	Always	10 kΩ or higher

Result


Proceed to
OK
NG

OK

GO TO ECD SYSTEM (ECM POWER SOURCE CIRCUIT)

for 2AD-FTV:
Click here
for 2AD-FHV:
Click here

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR