U02C0: Lost Communication With Active Radiator Air Flow Control Module A

What it means

The vehicle bus reports loss of communication with active radiator air flow control module A. Active grille shutters and electric cooling-fan staging on this circuit cannot be commanded.

At a glance

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

How it works

Active radiator air flow control module A operates the grille shutters and may coordinate electric cooling-fan stages. The vehicle network carries commands and status between this module and other controllers. This code sets when another controller cannot communicate with module A, so the affected shutters or fan staging may not respond as commanded.

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 for communication codes and note which controllers cannot reach module A, since a wider network fault points beyond the air-flow module itself.
2. Use freeze-frame data and available live network data to see when communication stopped and whether module A is currently reporting status.
3. With the vehicle safely parked and cool, inspect the active grille shutters, module A connector, and nearby harness for damage, water, corrosion, or loose connections.
4. Check the module's power and ground circuits under the conditions specified by the manufacturer, because a lost supply can look like a network failure.
5. Test the network wiring to module A for opens, shorts, and poor connections using the manufacturer's procedure, then assess the module if its wiring and supplies are sound.

Common fixes

• Reconnect or clean a loose or corroded module A connector and repair damaged wiring.
• Repair an open or short in the network wiring to the active radiator air flow control module.
• Restore the module's power or ground connection if testing identifies a supply fault.
• Replace module A if its power, ground, and network circuits test correctly but it remains offline.

Can I keep driving?

If the shutters or fan staging are inoperative, avoid heavy loads, high-speed driving, and prolonged idling, and watch the temperature gauge for overheating. Stop safely if the engine temperature rises or a temperature warning appears, since cooling problems can cause severe engine damage.