U0288: Lost Communication With DC/AC Converter Control Module A

What it means

The vehicle bus reports loss of communication with DC/AC inverter module A. Drive-motor torque commands or AC-outlet supply that route through this inverter are unavailable, putting the EV/hybrid drivetrain into a degraded mode.

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

DC/AC converter control module A manages its assigned inverter functions, which may support drive-motor power conversion or an AC outlet depending on the vehicle. The hybrid or EV control system expects messages from module A over the vehicle network; this code sets when those messages are lost and related functions may be disabled.

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 hybrid or EV modules for communication, isolation, and low-voltage supply codes, and preserve freeze-frame data.
2. Check whether converter control module A responds to the scan tool and which inverter functions or status data are unavailable.
3. Visually inspect module A's low-voltage connector and harness for looseness, corrosion, damage, or signs of water entry; do not disturb high-voltage components.
4. Check the module's low-voltage power and ground using the manufacturer's procedure.
5. Have the network wiring to module A tested for opens, shorts, or poor connections using the vehicle's specified shutdown and safety procedure.
6. If low-voltage supplies and network wiring are correct, use the manufacturer's high-voltage system diagnosis to confirm whether module A has failed.

Common fixes

• Secure a loose low-voltage connector at converter control module A.
• Repair damaged low-voltage wiring or network connections to module A.
• Restore the module's low-voltage power or ground supply.
• Replace module A only after its network and low-voltage circuits test correctly and the manufacturer's diagnosis confirms failure.

Can I keep driving?

If the vehicle shows reduced power, a hybrid or EV system warning, or enters limp mode, stop driving when safe and arrange service; loss of inverter functions can reduce propulsion or disable related power outlets. Do not touch high-voltage components.