U04A8: Invalid Data Received From Hybrid/EV Battery Interface Control Module H

A receiving module detected implausible data from hybrid/EV battery interface module H. Cell-voltage, current or temperature values fail plausibility checks against other inputs and are rejected.

High severity. Can I keep driving?If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

Symptoms

Multiple warning lights may illuminate
Affected modules may go into limp mode or shut down
Specific functions inoperative depending on module
Diagnostic tools may show communication faults

Most likely causes

Module internal fault or sensor input drift
Software version mismatch after replacement
Gateway module routing CAN messages incorrectly

What to check, in order

Start with the simplest. You can tick off each step.

Read the codes with a hybrid-compatible scanner and write down the freeze frame data
Make sure the battery cooling air intake is clean
Check the 12 V auxiliary battery, which can also trigger warnings
Leave any high-voltage measurements to a specialized repair shop

Good to know

Repair difficulty: hard
It can trigger limp mode.

What each character of U04A8 means

U: Communication network
0: Generic code: same on every make
4: Subsystem depends on the code range
A8: Specific fault in that system

Frequently asked questions

Can I keep driving with code U04A8?

If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

What causes code U04A8?

The most common causes are: module internal fault or sensor input drift; software version mismatch after replacement; gateway module routing CAN messages incorrectly.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.