Toyota Tundra Service Manual: ECM Power Source Circuit

Toyota Tundra Service Manual / Engine, Hybrid System / 1ur-fe Engine Control / Sfi System / ECM Power Source Circuit

DESCRIPTION

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

WIRING DIAGRAM

PROCEDURE

1.	INSPECT FUSES (AM2, IG2 MAIN, EFI NO. 1, IGN)

(a) Remove the IG2 MAIN fuse, EFI NO. 1 fuse and IGN fuse from the engine room relay block.

(b) Remove the AM2 fuse from the driver side junction block.

Standard Resistance:

Tester Connection	Condition	Specified Condition
AM2 fuse	Always	Below 1 Ω
IG2 MAIN fuse	Always	Below 1 Ω
EFI NO. 1 fuse	Always	Below 1 Ω
IGN fuse	Always	Below 1 Ω

CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE

2.	INSPECT INTEGRATION RELAY (IG2, EFI)

(a) Remove the integration 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
2C-1 - 2B-8	No battery voltage is applied to terminals 2B-6 and 2B-7	10 kΩ or higher
2C-1 - 2B-8	Battery voltage is applied to terminals 2B-6 and 2B-7	Below 1 Ω
2C-1 - 2B-4	No battery voltage is applied to terminals 2B-2 and 2B-3	10 kΩ or higher
2C-1 - 2B-4	Battery voltage is applied to terminals 2B-2 and 2B-3	Below 1 Ω

REPLACE INTEGRATION RELAY

3.	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:

Tester Connection	Condition	Specified Condition
D74-81 (E1) - Body ground	Always	Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	INSPECT ECM (IGSW VOLTAGE)

(a) Disconnect the ECM connectors.

(b) Turn the ignition switch to ON.

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
A24-28 (IGSW) - D74-81 (E1)	Ignition switch ON	11 to 14 V

REPLACE ECM

5.	CHECK HARNESS AND CONNECTOR (RELAY BLOCK - ECM, IGNITION SWITCH, BATTERY AND BODY GROUND)

(a) Disconnect the ECM connector.

(b) Disconnect the ignition switch connector.

(d) Disconnect the cable from the battery positive (+) terminal.

(e) Remove the AM2 fuse and integration relay.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A24-28 (IGSW) - 2B-8	Always	Below 1 Ω
2B-7 - Body ground	Always	Below 1 Ω
Positive (+) battery cable - 2C-1	Always	Below 1 Ω
Positive (+) battery cable - AM2 fuse terminal 1	Always	Below 1 Ω
J9-5 (AM2) - AM2 fuse terminal 2	Always	Below 1 Ω
J9-6 (IG2) - 2B-6	Always	Below 1 Ω
A24-28 (IGSW) or 2B-8 - Body ground	Always	10 kΩ or higher
Positive (+) battery cable or 2C-1 - Body ground	Always	10 kΩ or higher
Positive (+) battery cable or AM2 fuse terminal 1 - Body ground	Always	10 kΩ or higher
J9-5 (AM2) or AM2 fuse terminal 2 - Body ground	Always	10 kΩ or higher
J9-6 (IG2) or 2B-6 - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	INSPECT IGNITION SWITCH

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

REPLACE IGNITION SWITCH

7.	CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM, BATTERY AND BODY GROUND)

(a) Disconnect the ECM connector.

(b) Disconnect the cable from the battery negative (-) terminal.

(d) Remove the integration relay from the engine room relay block.

(e) Disconnect the integration relay connectors.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A24-3 (+B) - 2B-4	Always	Below 1 Ω
A24-2 (+B2) - 2B-4	Always	Below 1 Ω
A24-34 (MREL) - 2B-2	Always	Below 1 Ω
2C-1 - Positive (+) battery cable	Always	Below 1 Ω
2B-3 - Body ground	Always	Below 1 Ω
A24-3 (+B) or 2B-4 - Body ground	Always	10 kΩ or higher
A24-2 (+B2) or 2B-4 - Body ground	Always	10 kΩ or higher
A24-34 (MREL) or 2B-2 - Body ground	Always	10 kΩ or higher
2C-1 or Positive (+) battery cable - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE ENGINE ROOM RELAY BLOCK

REPAIR OR REPLACE HARNESS OR CONNECTOR

Dtc Check / Clear

EVAP System

See More:

Toyota Tundra Service Manual > Forward Recognition Camera System: Vehicle Speed Sensor Circuit (C1AA3)
DESCRIPTION The forward recognition camera receives vehicle speed signals from the skid control ECU (brake actuator assembly). If the skid control ECU (brake actuator assembly) receives a vehicle speed sensor malfunction signal, it informs the forward recognition camera via CAN communication, and DT ...

Toyota Tundra Service Manual: ECM Power Source Circuit

Dtc Check / Clear

EVAP System

See More:

Toyota Tundra Owners Manual

Toyota Tundra Service Manual