U04A3

Code

Generic U — Network/User

Invalid Data Received From Hybrid/EV Battery Interface Control Module C

Brand: Generic

Type: U — Network/User

Views: UK: 25 EN: 32 RU: 28

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

CAN/LIN communication errors on the battery network
Loose, corroded or damaged connectors/wiring to Battery Interface Module C
Battery Interface Module C internal fault or firmware corruption
Low or intermittent battery pack or 12V supply to the module
Missing or mismatched software/calibration between modules
High electrical noise, poor grounding, or bus termination problems

Symptoms

Malfunction Indicator Lamp (MIL)/Warning light related to hybrid/EV system
Reduced driveability or limited EV/hybrid operating modes
Battery pack or hybrid system warning messages displayed on cluster
Inability to charge, regenerate, or accept charge properly
Stored communication and data integrity trouble codes
Symptoms may be intermittent or present only under certain conditions (temperature, vibration)

What to check

Scan all modules and note freeze frame, stored and pending codes; record module identifiers and software levels
Visually inspect connectors, pins and wiring at Battery Interface Module C and associated junctions for corrosion, damage or loose pins
Verify battery pack and 12V supply voltages and ground integrity under static and loaded conditions
Check CAN bus physical layer: measure CAN_H and CAN_L idle voltages and look for shorts to battery/ground
Check CAN network termination resistances and continuity between nodes
Use a scan tool to monitor live data from Battery Interface Module C and compare to other battery modules for consistency

Signal parameters

CAN bus idle voltages: approximately CAN_H ~2.5 V, CAN_L ~2.5 V (recessive); dominant state alters approx. +1 V / −1 V
Differential CAN voltage when active: typically about 2.0 V (dominant)
Expected message frequency and IDs for Battery Interface Module C (verify with manufacturer documentation)
Error counters or bus-off events visible in module diagnostics
Battery Interface Module C module voltage: nominal pack and 12V supply ranges per vehicle spec

Diagnostic algorithm

Retrieve and record U04A3 plus any related codes from all modules; note freeze-frame and occurrence history.
Clear codes and attempt to reproduce the fault while monitoring live data from Battery Interface Module C and gateway modules.
Perform a visual inspection of the module C connector, wiring harness and mating connectors; repair any physical damage.
Verify 12V and pack supply voltage to the module and confirm good ground connections (measure under load if intermittent).
Check CAN bus physical layer: measure CAN_H/CAN_L idle voltages, perform a short-to-power/ground check and confirm proper termination resistance.
Use a diagnostic tool or oscilloscope to capture CAN frames from the bus to confirm valid messages, IDs, timing and error frames; compare to a known-good snapshot if available.
If bus and wiring are good, attempt a software/firmware update or reflash of the Battery Interface Module C if a calibrations mismatch or known fix exists.
If fault persists after wiring, power and software checks, consider module replacement or swap with a known-good unit (follow safety and immobilization procedures for high-voltage systems).
After repair or replacement, clear codes and perform a full system relearn or initialization procedures as required by the vehicle manufacturer, then verify normal operation.

Likely causes

Corroded/loose connector or damaged CAN wiring to Battery Interface Module C
Faulty or intermittent power/ground to the module
Communication bus errors due to missing termination or excessive noise
Module firmware/software incompatibility or known module fault

Fault status

⚠️ Status

Invalid data received from Hybrid/EV Battery Interface Control Module C — indicates communication or data integrity fault between module C and the vehicle network.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5 - 4.0 hours