Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

2008 Toyota Sequoia SR5, 5.7 Y, RWDFACTORY OEM SERVICE PROCEDURE

Inspection Procedure

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

Remove the AM2 fuse, IG2 MAIN fuse, EFI NO. 1 fuse and IGN fuse from the engine room relay block.

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

Standard Resistance

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

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

Fig 1: Identifying AM2 Fuse, IG2 MAIN Fuse, EFI NO. 1 Fuse And IGN Fuse

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to Next Step

INSPECT RELAY (IG2, EFI MAIN)

Remove the integration relay from the engine room relay block.

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

Standard Resistance

STANDARD RESISTANCE

Tester Connection	Condition	Specified Condition
1C-1 -1B-8	When no battery voltage is applied to terminals 1B-6 and 1B-7	10 kΩ or higher
1C-1 -1B-8	When battery voltage is applied to terminals 1B-6 and 1B-7	Below 1 Ω
1C-1 -1B-4	When no battery voltage is applied to terminals 1B-2 and 1B-3	10 kΩ or higher
1C-1 -1B-4	When battery voltage is applied to terminals 1B-2 and 1B-3	Below 1 Ω

NG: REPLACE RELAY

Fig 2: Identifying Integration Relay Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

Disconnect the ECM connector.

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

Standard Resistance

STANDARD RESISTANCE

Tester Connection	Condition	Specified Condition
D56-81 (E1)-Body ground	Always	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 3: Identifying ECM Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to Next Step.

INSPECT ECM (IGSW VOLTAGE)

Disconnect the ECM connectors.
Turn the ignition switch to ON.

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

Standard Voltage

STANDARD VOLTAGE

Tester Connection	Switch Condition	Specified Condition
A27-28 (IGSW) - D56-81 (E1)	Ignition switch ON	11 to 14 V

NG: Go to step 5

Fig 4: Identifying ECM Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: REPLACE ECM (See REMOVAL )

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

Disconnect the ECM connector.
Disconnect the ignition switch connector.
Disconnect the cable from the battery positive (+) terminal.
Remove the AM2 fuse and integration relay.

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

Standard Resistance

STANDARD RESISTANCE

Tester Connection	Condition	Specified Condition
A27-28(IGSW) - 1B-8	Always	Below 1 Ω
1B-7 - Body ground	Always	Below 1 Ω
Positive (+) battery cable - 1C-1	Always	Below 1 Ω
Positive (+) battery cable - AM2 fuse terminal 1	Always	Below 1 Ω
H10-5 (AM2) - AM2 fuse terminal 2	Always	Below 1 Ω
H10-6(IG2) - 1B-6	Always	Below 1 Ω
A27-28(IGSW) or 1B-8-Body ground	Always	10 kΩ or higher
Positive (+) battery cable or AM2 fuse terminal 1 - Body ground	Always	10 kΩ or higher
Positive (+) battery cable or 1C-1 - Body ground	Always	10 kΩ or higher
H10-5(AM2) or AM2 fuse terminal 2 - Body ground	Always	10 kΩ or higher
H10-6(IG2) or 1B-6-Body ground	Always	10 kΩ or higher

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 5: Identifying ECM And Ignition Switch Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to Next Step.

INSPECT IGNITION SWITCH (See INSPECTION PROCEDURE )
NG: REPLACE IGNITION SWITCH (See REMOVAL )

OK: Go to Next Step.

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

Disconnect the ECM connector.
Disconnect the cable from the battery positive terminal.
Remove the integration relay from the engine room relay block.
Disconnect the integration relay connector.

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

Standard Resistance

STANDARD RESISTANCE

Tester Connection	Condition	Specified Condition
A27-3(+B) - 1B-4	Always	Below 1
A27-2(+B2) - 1B-4	Always	Below 1
A27-34(MREL) - 1B-2	Always	Below 1
1C-1 - Positive (+) battery cable	Always	Below 1
1B-3 - Body ground	Always	Below 1
A27-3(+B) or 1B-4-Body ground	Always	10 k or higher
A27-2(+B2) or 1B-4-Body ground	Always	10 k or higher
A27-34(MREL) or 1B-2-Body ground	Always	10 k or higher
1C-1 or Positive (+) battery cable - Body ground	Always	10 k or higher

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig 6: Identifying ECM And Integration Relay Connector Terminals

OK: REPAIR OR REPLACE ENGINE ROOM RELAY BLOCK

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.

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