B15A8 on Lexus
Telematics Transceiver Malfunction
B15A8 on Lexus vehicles indicates telematics transceiver malfunction. Au7o has documented this code across 1 Lexus model — most commonly on UX. Set by the Data Communication Module (DCM, the telematics transceiver) when its power-on self-check finds an internal error in the EEPROM (which stores the data needed to operate the Safety Connect system) or in the PLL IC (which oscillates the cellular radio frequency). It is an internal-module fault, not a wiring-continuity fault, though a poor connection at the DCM connector can also set it. Toyota has documented that this DTC can be stored during manufacturing and shipping without indicating any real vehicle defect.
Common Causes of B15A8
- •Internal EEPROM or PLL IC failure inside the DCM / telematics transceiver
- •Poor electrical connection or corrosion at the DCM connector
- •DCM firmware fault (including the DCM firmware that keeps the module awake and drains the 12V battery)
- •Code stored during vehicle manufacture or shipping with no actual fault present
B15A8 on Lexus by Model
Lexus UX(1 issue)
- Safety Connect SOS Button and DCM Telematics Fail - Red SOS LED Stays On, DTC B15A8042019-2022
The UX's Data Communication Module (DCM) drives Safety Connect - the emergency SOS call button in the overhead console, automatic collision notification, and stolen vehicle locator. Lexus issued a sequence of bulletins on this module: L-SB-0032-20 (August 2020, revised September 2021) covering an inoperative SOS button and an inoperative Bluetooth microphone on vehicles with the Continental-supplied DCM, and L-SB-0036-21 (October 2021, superseding L-SB-0036-20) covering a red SOS LED that stays illuminated after the bulb check with DTC B15A804 stored. Related bulletins cover telematics going dead after a DCM replacement (L-TT-0293-20) and Lexus Enform Remote app inoperability (L-TT-0279-20). The practical consequence is that the car's crash-notification safety feature is silently dead - the red LED is often the only clue - and the hands-free microphone frequently fails at the same time because both run through the DCM. Because the same module is shared across both powertrains, this affects UX 200 and UX 250h alike.
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View B15A8 across all makes →Frequently Asked Questions
What does B15A8 mean on Lexus?▼
B15A8 stands for "Telematics Transceiver Malfunction." Set by the Data Communication Module (DCM, the telematics transceiver) when its power-on self-check finds an internal error in the EEPROM (which stores the data needed to operate the Safety Connect system) or in the PLL IC (which oscillates the cellular radio frequency). It is an internal-module fault, not a wiring-continuity fault, though a poor connection at the DCM connector can also set it. Toyota has documented that this DTC can be stored during manufacturing and shipping without indicating any real vehicle defect. On Lexus specifically, this code is documented across 1 model.
What causes B15A8 on Lexus vehicles?▼
Common causes on Lexus: Internal EEPROM or PLL IC failure inside the DCM / telematics transceiver, Poor electrical connection or corrosion at the DCM connector, DCM firmware fault (including the DCM firmware that keeps the module awake and drains the 12V battery), Code stored during vehicle manufacture or shipping with no actual fault present. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix B15A8 on a Lexus?▼
Repair costs vary widely depending on the root cause and specific Lexus model.
Which Lexus models have B15A8 documented?▼
Au7o has documented B15A8 on 1 Lexus model: UX.