DTC B228B-00: Battery Circuit or Ground Circuit Energization Malfunction [10/2022 - ]: Procedure
WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK HARNESS AND CONNECTOR (POWER SOURCE)
Pre-procedure1
- Disconnect the C51 certification ECU (smart key ECU assembly) connector.
- Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Condition Specified Condition Result C51-6 (+B) - Body ground Ignition switch off 11 to 14 V V Result
Proceed to OK NG
Post-procedure1
- None
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR IN CIRCUIT CONNECTED TO POWER SOURCE
Result:
OK
See step 2
- CHECK HARNESS AND CONNECTOR (GROUND)
- Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition Result C51-29 (E) - Body ground Always Below 1 Ω Ω Result
Proceed to OK NG
Result:
OK
END (TEMPORARY CONNECTION FAILURE IS SUSPECTED). Refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR IN CIRCUIT CONNECTED TO POWER SOURCE
- Measure the resistance according to the value(s) in the table below.