U04AD: Invalid Data Received From Hybrid/EV Battery Interface Control Module M

What it means

A control module received invalid data from hybrid/EV battery interface control module M. The code identifies a data validity fault; the specific affected function depends on the vehicle.

At a glance

• Usually lights the warning light of the system that lost communication
• The engine or gearbox may go into limp mode

How it works

Hybrid and EV battery interface control modules send battery-related information over the vehicle network to other modules. A receiving module sets U04AD when data from interface control module M fails its validity checks; the code does not identify which battery function is affected.

Common causes

Most likely first.

1. Fault in the transmitting module
2. Network wiring or connector fault
3. Module power or ground fault
4. Software or configuration mismatch

Symptoms

• Hybrid or EV battery warnings may appear
• Battery or vehicle performance may be limited

How to diagnose it

1. Record freeze-frame data and scan all modules for communication or battery codes to see whether the fault is limited to module M or part of a wider network problem.
2. Check live data and code status for messages attributed to module M, noting whether invalid data appears continuously or intermittently.
3. Inspect module M's accessible connectors and network wiring for looseness, corrosion, moisture, damage, or signs of recent repairs.
4. Check the relevant module power and ground circuits under load against the manufacturer's specification, since unstable supply can corrupt messages.
5. Test the network wiring and connections serving module M using the vehicle's wiring information and manufacturer's procedures.
6. If wiring and supplies pass, verify module M's software and configuration are correct, then assess the module for an internal fault.

Common fixes

• Reconnect and secure a loose module M connector; clean or repair corroded terminals as appropriate.
• Repair damaged network wiring or connector terminals serving module M.
• Repair a faulty power or ground connection to module M.
• Correct a software or configuration mismatch using the manufacturer's approved procedure.
• Replace or repair module M if testing confirms it is faulty and the vehicle's service procedure supports that repair.

Can I keep driving?

Because battery-related information may be unreliable and the vehicle may limit performance, avoid high-speed, long-distance, or high-load driving while warnings or reduced power are present. Stop safely if the vehicle behaves unpredictably or displays a battery safety warning, and arrange diagnosis.