ECM Power Source Circuit: Procedure
- INSPECT FUSES (IG2 MAIN, EFI MAIN AND IGN)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Remove the IG2 MAIN fuse, EFI MAIN fuse and IGN fuse from the engine room relay block.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition IG2 MAIN fuse Always Below 1 Ω EFI MAIN 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
OK: Go to next step
- INSPECT RELAY (IG2, EFI)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Remove the integration relay from the engine room relay block.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition 1C-1 - 1B-8 Battery voltage not applied 10 kΩ or higher Battery voltage applied to terminals 1B-6 and 1B-7 Below 1 Ω 1C-1 - 1B-4 Battery voltage not applied 10 kΩ or higher Battery voltage applied to terminals 1B-2 and 1B-3 Below 1 Ω
NG → REPLACE RELAY
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)
- Disconnect the C53 ECM connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition C53-81 (E1) - Body ground Always Below 1 Ω
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (RELAY BLOCK - ECM, MAIN BODY ECU, BATTERY)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Disconnect the A38 ECM connector.
- Disconnect the E2 main body ECU connector.
- Disconnect the cable from the battery positive (+) terminal.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A38-28 (IGSW) - 1B-8 Always Below 1 Ω 1B-7 - Body ground Always Below 1 Ω Positive (+) battery cable - 1C-1 Always Below 1 Ω E2-11 (IG2D) - 1B-6 Always Below 1 Ω A38-28 (IGSW) or 1B-8 - Body ground Always 10 kΩ or higher Positive (+) battery cable or 1C-1 - Body ground Always 10 kΩ or higher E2-11 (IG2D) or 1B-6 - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- INSPECT ECM (IGSW VOLTAGE)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Disconnect the A38 and C53 ECM connectors.
- Turn the engine switch on (IG).
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Switch Condition Specified Condition A38-28 (IGSW) - C53-81 (E1) Engine switch on (IG) 11 to 14 V
NG → See step 6
OK → See step 7
- CHECK SMART ACCESS SYSTEM WITH PUSH-BUTTON START (POWER SOURCE MODE DOES NOT CHANGE)
- Check the smart access system with push-button start. Refer to Power Source Mode does not Change .
NG → REPAIR SMART ACCESS SYSTEM WITH PUSH-BUTTON START
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM, BATTERY AND BODY GROUND)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- Disconnect the A38 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
Tester Connection Condition Specified Condition A38-3 (+B) - 1B-4 Always Below 1 Ω A38-2 (+B2) - 1B-4 Always Below 1 Ω A38-34 (MREL) - 1B-2 Always Below 1 Ω 1C-1 - Positive (+) battery cable Always Below 1 Ω 1B-3 - Body ground Always Below 1 Ω A38-3 (+B) or 1B-4 - Body ground Always 10 kΩ or higher A38-2 (+B2) or 1B-4 - Body ground Always 10 kΩ or higher A38-34 (MREL) or 1B-2 - Body ground Always 10 kΩ or higher 1C-1 or Positive (+) battery cable - Body ground Always 10 kΩ or higher
NG → REPAIR OR REPLACE HARNESS OR CONNECTOR
OK → See step 8
- REPLACE ECM. Refer to REMOVAL