What it means
A receiving module detected implausible data from the radiator anti-tamper device. Tamper-detection state values fail plausibility checks and are rejected.
How it works
The Radiator Anti-Tamper Device reports its tamper-detection state to other vehicle modules. U0587 is set when a receiving module rejects that state data as implausible; it does not by itself confirm tampering or a radiator fault.
Common causes
Most likely first.
- Module internal fault or sensor input drift
- Software version mismatch after replacement
- 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
- Scan all modules and save freeze-frame and communication codes to identify which module rejected the anti-tamper data and whether the fault is current.
- Check live data for the Radiator Anti-Tamper Device state and compare it with any related radiator or security warnings.
- Inspect the device, its mounting, connectors, and harness for damage, displacement, corrosion, or signs of disturbed wiring.
- Check the device's power, ground, and network circuits against the wiring diagram and manufacturer's specification.
- If wiring passes, check for module software or configuration issues and test gateway routing and device messages using the manufacturer's procedure.
Common fixes
- Secure a displaced anti-tamper device and reconnect its connector correctly.
- Repair damaged or corroded wiring and connectors at the device.
- Correct the module software or configuration if an update or replacement introduced a mismatch.
- Replace the Radiator Anti-Tamper Device if it continues to report implausible states after circuit checks.
- Repair the gateway only if network testing confirms it is misrouting the device's data.
Can I keep driving?
The code may affect tamper monitoring rather than engine operation, but heed any coolant-temperature warning. Stop if the engine overheats and have the anti-tamper fault checked if it persists.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.