Last Modified: 11-20-2023 6.11:8.1.0 Doc ID: RM10000000138MA
Model Year Start: 2018 Model: Camry Prod Date Range: [03/2017 -           ]
Title: A25A-FKS (ENGINE CONTROL): SFI SYSTEM: ECM Power Source Circuit; 2018 - 2024 MY Camry [03/2017 -        ]

ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, the battery voltage is applied to IGSW of the ECM. When the transistor in the MREL circuit operates, current flows from the battery to ground through the drive circuit of the EFI-MAIN NO. 1 relay, thus operating the relay which supplies power to the +B and +B2 terminals of the ECM.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following 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:

Tester Connection

Condition

Specified Condition

A24-10 (E1) - Body ground

Always

Below 1 Ω
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

2.

CHECK TERMINAL VOLTAGE (IGSW TERMINAL VOLTAGE)

*a

Front view of wire harness connector

(to ECM)

(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

Condition

Specified Condition

A24-2 (IGSW) - Body ground

Ignition switch ON

11 to 14 V
NG

GO TO STEP 6

OK

3.

INSPECT EFI-MAIN NO. 1 RELAY

(a) Inspect the EFI-MAIN NO. 1 relay.

Click here 2018 - 2024 MY Camry [03/2017 -        ]; A25A-FKS (ENGINE CONTROL): RELAY: ON-VEHICLE INSPECTION+

NG

REPLACE EFI-MAIN NO. 1 RELAY
OK

4.

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

(a) Disconnect the ECM connector.

(b) Remove the EFI-MAIN NO. 1 relay from the engine room relay block and junction block assembly.

HINT:

Remove the VVT, EFI-MAIN NO. 2 and EFI-MAIN NO. 3 relays connected between the checked terminals as the coil inside the relay influences the measurement value.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

2 (EFI-MAIN NO. 1 relay) - A24-15 (MREL)

Always

Below 1 Ω

5 (EFI-MAIN NO. 1 relay) - A24-9 (+B)

Always

Below 1 Ω

5 (EFI-MAIN NO. 1 relay) - A24-35 (+B2)

Always

Below 1 Ω

2 (EFI-MAIN NO. 1 relay) or A24-15 (MREL) - Body ground and other terminals

Always

10 kΩ or higher

5 (EFI-MAIN NO. 1 relay), A24-9 (+B) or A24-35 (+B2) - Body ground and other terminals

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

CHECK TERMINAL VOLTAGE (POWER SOURCE OF EFI-MAIN NO. 1 RELAY)

*1

Engine Room Relay Block and Junction Block Assembly

*2

EFI-MAIN NO. 1 Relay

(a) Remove the EFI-MAIN NO. 1 relay from the engine room relay block and junction block assembly.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

3 (EFI-MAIN NO. 1 relay) - Body ground

Always

11 to 14 V

1 (EFI-MAIN NO. 1 relay) - Body ground

Always

11 to 14 V
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 2018 MY Camry [03/2017 - 06/2017]; A25A-FKS (ENGINE CONTROL): SFI SYSTEM: PROBLEM SYMPTOMS TABLE 2018 MY Camry [06/2017 - 08/2018]; A25A-FKS (ENGINE CONTROL): SFI SYSTEM: PROBLEM SYMPTOMS TABLE 2019 MY Camry [08/2018 - 09/2019]; A25A-FKS (ENGINE CONTROL): SFI SYSTEM: PROBLEM SYMPTOMS TABLE 2020 MY Camry [09/2019 - 03/2020]; A25A-FKS (ENGINE CONTROL): SFI SYSTEM: PROBLEM SYMPTOMS TABLE 2020 - 2024 MY Camry [03/2020 -        ]; A25A-FKS (ENGINE CONTROL): SFI SYSTEM: PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI-MAIN NO. 1 RELAY)

6.

INSPECT IG2 NO. 1 RELAY

(a) Inspect the IG2 NO. 1 relay.

Click here 2018 - 2024 MY Camry [03/2017 -        ]; A25A-FKS (ENGINE CONTROL): RELAY: ON-VEHICLE INSPECTION+

NG

REPLACE IG2 NO. 1 RELAY
OK

7.

CHECK HARNESS AND CONNECTOR (IG2 NO. 1 RELAY - ECM)

(a) Disconnect the ECM connector.

(b) Remove the IG2 NO. 1 relay from the engine room relay block and junction block assembly.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 (IG2 NO. 1 relay) - A24-2 (IGSW)

Always

Below 1 Ω

3 (IG2 NO. 1 relay) or A24-2 (IGSW) - Body ground and other terminals

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

8.

CHECK TERMINAL VOLTAGE (POWER SOURCE OF IG2 NO. 1 RELAY)

*1

Engine Room Relay Block and Junction Block Assembly

*2

IG2 NO. 1 Relay

(a) Remove the IG2 NO. 1 relay from the engine room relay block and junction block assembly.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

5 (IG2 NO. 1 relay) - Body ground

Always

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IG2 NO. 1 RELAY)
OK

9.

CHECK HARNESS AND CONNECTOR (IG2 NO. 1 RELAY - BODY GROUND)

(a) Remove the IG2 NO. 1 relay from the engine room relay block and junction block assembly.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

2 (IG2 NO. 1 relay) - Body ground

Always

Below 1 Ω

Result

Proceed to

OK (w/ Smart Key System)

A

OK (w/o Smart Key System)

B

NG

C
B

GO TO STEP 11

C

REPAIR OR REPLACE HARNESS OR CONNECTOR
A

10.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - IG2 NO. 1 RELAY)

(a) Disconnect the certification ECU (smart key ECU assembly) connector.

(b) Remove the IG2 NO. 1 relay from the engine room relay block and junction block assembly.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

K62-17 (IG1D) - 1 (IG2 NO. 1 relay)

Always

Below 1 Ω

K62-17 (IG1D) or 1 (IG2 NO. 1 relay) - Body ground and other terminals

Always

10 kΩ or higher
OK

GO TO SMART KEY SYSTEM 2018 - 2022 MY Camry [03/2017 - 08/2022]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function): HOW TO PROCEED WITH TROUBLESHOOTING 2023 - 2024 MY Camry [08/2022 -        ]; THEFT DETERRENT / KEYLESS ENTRY: SMART KEY SYSTEM (for Start Function): HOW TO PROCEED WITH TROUBLESHOOTING

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

11.

INSPECT IGNITION SWITCH ASSEMBLY

(a) Inspect the ignition switch assembly.

Click here 2018 - 2024 MY Camry [03/2017 -        ]; A25A-FKS (STARTING): IGNITION SWITCH: INSPECTION

NG

REPLACE IGNITION SWITCH ASSEMBLY

OK

12.

CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - IG2 NO. 1 RELAY)

(a) Disconnect the ignition switch assembly connector.

(b) Remove the IG2 NO. 1 relay from the engine room relay block and junction block assembly.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

K30-8 (IG1) - 1 (IG2 NO. 1 relay)

Always

Below 1 Ω

K30-8 (IG1) or 1 (IG2 NO. 1 relay) - Body ground and other terminals

Always

10 kΩ or higher
OK

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

REPAIR OR REPLACE HARNESS OR CONNECTOR