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Home / DTC / U04A3 — Invalid Data Received From Hybrid/EV Battery Interface Control Module C

U04A3 — Invalid Data Received From Hybrid/EV Battery Interface Control Module C

Detailed page for trouble code U04A3.

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U04A3

Generic U — Network/User

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

Brand: Generic
Type: U — Network/User
Views: UK: 13 EN: 19 RU: 17
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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

  1. Retrieve and record U04A3 plus any related codes from all modules; note freeze-frame and occurrence history.
  2. Clear codes and attempt to reproduce the fault while monitoring live data from Battery Interface Module C and gateway modules.
  3. Perform a visual inspection of the module C connector, wiring harness and mating connectors; repair any physical damage.
  4. Verify 12V and pack supply voltage to the module and confirm good ground connections (measure under load if intermittent).
  5. Check CAN bus physical layer: measure CAN_H/CAN_L idle voltages, perform a short-to-power/ground check and confirm proper termination resistance.
  6. 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.
  7. 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.
  8. 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).
  9. 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

Similar codes

U04A0 U04A1 U04A2 U04A4 U0401 U0100
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