Ignition Circuit [08/2020 - ]: Procedure
WARNING: This page is about a different car, the 2024 Lexus ES 250, 2023 Lexus ES 250, 2022 Lexus ES 250, and 2021 Lexus ES 250. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK TERMINAL VOLTAGE (POWER SOURCE OF IGNITION COIL ASSEMBLY)
*a Front view of wire harness connector
(to Ignition Coil Assembly)- Disconnect the ignition coil assembly connectors.
- Turn the engine switch on (IG).
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition C45-1 (+B) - C45-3 (GND) Engine switch on (IG) 11 to 14 V C46-1 (+B) - C46-3 (GND) Engine switch on (IG) 11 to 14 V C47-1 (+B) - C47-3 (GND) Engine switch on (IG) 11 to 14 V C48-1 (+B) - C48-3 (GND) Engine switch on (IG) 11 to 14 V Result
Proceed to OK NG
Result:
NG
See step 3
Result:
OK
See step 2
- CHECK HARNESS AND CONNECTOR (IGNITION COIL ASSEMBLY - ECM)
- Disconnect the ignition coil assembly connectors.
- Disconnect the ECM connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition C45-2 (IGT1) - C77-49 (IGT1) Always Below 1 Ω C46-2 (IGT2) - C77-48 (IGT2) Always Below 1 Ω C47-2 (IGT3) - C77-47 (IGT3) Always Below 1 Ω C48-2 (IGT4) - C77-46 (IGT4) Always Below 1 Ω C45-2 (IGT1) or C77-49 (IGT1) - Body ground and other terminals Always 10 kΩ or higher C46-2 (IGT2) or C77-48 (IGT2) - Body ground and other terminals Always 10 kΩ or higher C47-2 (IGT3) or C77-47 (IGT3) - Body ground and other terminals Always 10 kΩ or higher C48-2 (IGT4) or C77-46 (IGT4) - Body ground and other terminals Always 10 kΩ or higher Result
Proceed to OK NG
Result:
OK
REPLACE ECM. Refer to REMOVAL [08/2020 - 08/2021] , or refer to REMOVAL [08/2021 - 09/2022] , or refer to REMOVAL [09/2022 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
- CHECK HARNESS AND CONNECTOR (IGNITION COIL ASSEMBLY - BODY GROUND)
- Disconnect the ignition coil assembly connectors.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition C45-3 (GND) - Body ground Always Below 1 Ω C46-3 (GND) - Body ground Always Below 1 Ω C47-3 (GND) - Body ground Always Below 1 Ω C48-3 (GND) - Body ground Always Below 1 Ω Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 4
- CHECK HARNESS AND CONNECTOR (IG2 NO. 1 RELAY - IGNITION COIL ASSEMBLY)
- Disconnect the IG2 NO. 1 relay from No. 1 engine room relay block and No. 1 junction block assembly.
- Disconnect the ignition coil assembly connectors.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition 3 (IG2 NO. 1 relay) - C45-1 (+B) Always Below 1 Ω 3 (IG2 NO. 1 relay) - C46-1 (+B) Always Below 1 Ω 3 (IG2 NO. 1 relay) - C47-1 (+B) Always Below 1 Ω 3 (IG2 NO. 1 relay) - C48-1 (+B) Always Below 1 Ω 3 (IG2 NO. 1 relay) or C45-1 (+B) - Body ground and other terminals Always 10 kΩ or higher 3 (IG2 NO. 1 relay) or C46-1 (+B) - Body ground and other terminals Always 10 kΩ or higher 3 (IG2 NO. 1 relay) or C47-1 (+B) - Body ground and other terminals Always 10 kΩ or higher 3 (IG2 NO. 1 relay) or C48-1 (+B) - Body ground and other terminals Always 10 kΩ or higher Result
Proceed to OK NG
Result:
OK
GO TO ECM POWER SOURCE CIRCUIT. Refer to ECM Power Source Circuit [08/2020 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR