U05C1: Invalid Data Received From Active Radiator Air Flow Control Module A

What it means

A receiving module detected implausible data from active radiator air flow control module A. Active grille shutter or fan staging values fail plausibility checks and are rejected.

At a glance

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

How it works

Active radiator air flow control module A manages the active grille shutter or other airflow hardware assigned to it and may report shutter position or fan staging. A receiving module sets U05C1 when those reports fail its plausibility checks and are rejected.

Common causes

Most likely first.

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

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 the engine and network modules for freeze-frame data, related cooling-system codes, and the identity of the module that stored U05C1.
2. Check for an engine warning, overheating, or an active grille shutter that is visibly stuck, obstructed, or damaged.
3. With the vehicle off and cool, inspect module A’s connectors and wiring, plus accessible shutter linkages, for damage, corrosion, debris, or a disconnected harness.
4. Use a scan tool to compare commanded and reported shutter position or fan staging, if available, and observe whether the hardware responds.
5. Check module power, ground, and network communication to the manufacturer’s specification; if the module or gateway was replaced, verify compatible software and configuration.

Common fixes

• Remove debris or repair a damaged or binding active grille shutter mechanism.
• Repair loose, corroded, or damaged wiring or connectors at airflow control module A.
• Restore specified power, ground, or network connections.
• Correct software or configuration incompatibility after module replacement.
• Diagnose or replace module A if its reported airflow data remains implausible after mechanical and circuit checks.

Can I keep driving?

Avoid driving if the engine is overheating, and stop safely if the temperature warning appears. If temperatures remain normal, keep trips short and monitor the gauge because incorrect shutter or fan control can lead to overheating or reduced cooling performance.