TCM Power Source Circuit [11/2021 - ]: Procedure
WARNING: This page is about a different car, the 2024 Lexus IS 500, 2023 Lexus IS 500, and 2022 Lexus IS 500. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK HARNESS AND CONNECTOR (TCM - BODY GROUND)
- Turn the engine switch off.
- Disconnect the A118 TCM connectors.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A118-2 (E1) - Body ground Always Below 1 Ω Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (TCM - BODY GROUND)
Result:
OK
See step 2
- CHECK HARNESS AND CONNECTOR (NO. 2 ENGINE ROOM RELAY BLOCK AND NO. 2 JUNCTION BLOCK ASSEMBLY - TCM)
- Disconnect the 2G No. 2 engine room relay block and No. 2 junction block assembly connector.
- Disconnect the A118 TCM connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition 2G-7 - A118-5 (+B) Always Below 1 Ω 2G-7 or A118-5 (+B) - Body ground Always 10 kΩ or higher Result
Proceed to OK NG
Result:
OK
GO TO ECM POWER SOURCE CIRCUIT (ENGINE CONTROL SYSTEM / SFI SYSTEM). Refer to ECM Power Source Circuit [11/2021 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 2 ENGINE ROOM RELAY BLOCK AND NO. 2 JUNCTION BLOCK ASSEMBLY - TCM)