LEMON Manuals: Even more car manuals for everyone
Home >> Lexus >> 2024 >> RX 500h >> Repair and Diagnosis >> External Pages >> Different car >> Section 106 (Hybrid Control System - Diagnostic Codes (7 Of 7) & Circuit Tests) >> HYBRID CONTROL SYSTEM (for THS-HEV Model) >> DTC U029A-87: Lost Communication with Hybrid/EV Battery Sensor Module Missing Message [10/2022 - ] >> Description

DTC U029A-87: Lost Communication with Hybrid/EV Battery Sensor Module Missing Message [10/2022 - ]: Description

WARNING: This page is about a different car, the 2025 Lexus RX 350h, 2024 Lexus RX 350h, and 2023 Lexus RX 350h. However, it is still accessible from the selected car via links, so may be relevant.

The battery voltage sensor detects the HV battery conditions (voltage, current and temperature) and the battery cooling fan frequency, and sends the detected signals to the hybrid vehicle control ECU via serial communication. (The hybrid vehicle control ECU does not send signals to the battery voltage sensor.)

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Warning Indicate DTC Output from Priority Note
U029A-87 Lost Communication with Hybrid/EV Battery Sensor Module Missing Message Serial communication error between the hybrid vehicle control ECU and battery voltage sensor: The hybrid vehicle control ECU cannot receive signals from the battery voltage sensor correctly.
(1 trip detection logic)
  • Hybrid vehicle control ECU
  • Battery voltage sensor
  • Wire harness or connector
Comes on Master Warning:
Comes on
Hybrid Control B SAE Code:
U029A