DTC P0615-19: Starter Relay Circuit Current Above Threshold [11/2021 - 03/2023]: Procedure
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2025 Lexus NX 350, 2025 Lexus NX 250, 2024 Lexus NX 350, 2024 Lexus NX 250, and 2023 Lexus NX 350. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - BBC FUSE)
- Disconnect the engine stop and start ECU connector.
- Remove the BBC NO. 1 and BBC NO. 2 fuses from the No. 1 engine room relay block and No. 1 junction block assembly.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A28-1 (BIN2) - BBC NO. 2 fuse terminal 2 Always Below 1 Ω A28-3 (BIN1) - BBC NO. 1 fuse terminal 2 Always Below 1 Ω A28-1 (BIN2) - Body ground Always 10 kΩ or higher A28-3 (BIN1) - Body ground Always 10 kΩ or higher BBC NO. 1 fuse terminal 2 - Body ground Always 10 kΩ or higher BBC NO. 2 fuse terminal 2 - Body ground Always 10 kΩ or higher Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 2
- CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - ST NO. 1 RELAY)
- Disconnect the engine stop and start ECU connectors.
- Remove the ST NO. 1 relay from the No. 1 engine room relay block and No. 1 junction block assembly.
- Remove the BBC NO. 1 and BBC NO. 2 fuses from the No. 1 engine room relay block and No. 1 junction block assembly.
- Disconnect the certification ECU (smart key ECU assembly) connector.
- Disconnect the ECM connector.
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A29-21 (STA) - ST NO. 1 relay terminal 2 Always Below 1 Ω A29-21 (STA) - Body ground Always 10 kΩ or higher ST NO. 1 relay terminal 2 - Body ground Always 10 kΩ or higher A28-1 (BIN2) - A29-21 (STA) Always 10 kΩ or higher A28-3 (BIN1) - A29-21 (STA) Always 10 kΩ or higher Result
Proceed to OK NG
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
Result:
OK
See step 3
- CHECK ENGINE STOP AND START ECU
- Disconnect the engine stop and start ECU connector.
*a Component without harness connected
(Engine Stop and Start ECU)- - - Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition A29-21 (STA) - A29-6 (DGND) Always 10 kΩ or higher Result
Proceed to OK NG
Result:
NG
REPLACE ENGINE STOP AND START ECU. Refer to REMOVAL [11/2021 - ]
Result:
OK
See step 4
- Disconnect the engine stop and start ECU connector.
- INSPECT RELAY (ST NO. 1 RELAY)
- Inspect the ST NO. 1 relay.
for T24A-FTS: Refer to ON-VEHICLE INSPECTION [11/2021 - ]
for A25A-FKS: Refer to ON-VEHICLE INSPECTION [11/2021 - ]
Result
Proceed to OK NG
Result:
OK
USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - ]
Result:
NG
REPLACE RELAY (ST NO. 1 RELAY)
- Inspect the ST NO. 1 relay.