U061E: Lost Communication With Battery Isolation/Voltage Stabilization Control Module

What it means

The vehicle bus reports loss of communication with the battery isolation / voltage stabilization module (typical in start/stop systems). Cranking voltage stabilization and second-battery switching cannot be commanded.

At a glance

• Usually lights the warning light of the system that lost communication

How it works

The battery isolation and voltage stabilization control module manages functions such as second-battery switching and support for cranking voltage on some start/stop vehicles. U061E sets when expected network messages from that module are missing, so other modules cannot reliably command those functions.

Common causes

Most likely first.

1. Bus wiring open or shorted
2. Module without power or ground
3. Module failed

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

How to diagnose it

1. Scan all modules and save freeze-frame data to determine whether the lost message occurred with other network faults or a low-voltage event.
2. Check battery condition and system voltage, and inspect the module's fuses and power connections using the manufacturer's wiring information.
3. Inspect the module connector, ground, and nearby network wiring for corrosion, loose terminals, or physical damage.
4. Verify the module's power and ground under the manufacturer's specified test conditions.
5. Test the relevant network circuit for opens and shorts according to the vehicle wiring diagram.
6. If supply and network tests pass, confirm the module is not communicating before considering replacement.

Common fixes

• Clean and secure corroded or loose battery and module connections.
• Replace a failed fuse or repair the module's power or ground wiring.
• Repair damaged network wiring or connector terminals.
• Replace the control module if its power, ground, and network circuit are sound but it remains offline.

Can I keep driving?

If the vehicle starts and drives normally, a short cautious trip may be possible, but start/stop and voltage support functions may not work as intended. Avoid repeated start-stop cycles if starting becomes unreliable, and get the fault checked before depending on the vehicle.