The U0587 code indicates that a control module (typically the PCM) has received invalid or implausible data from the radiator anti-tamper device. This device is designed to detect unauthorized access or tampering with the cooling system, often for emissions or security compliance. The code sets when the data signal from the device is missing, corrupted, or outside expected parameters.
The device itself may have failed internally, causing it to send invalid or no data to the receiving module.
Damaged, corroded, or loose wiring/connectors between the device and the control module can disrupt data transmission.
A short, open, or interference on the vehicle's communication network can corrupt the data signal from the anti-tamper device.
Outdated or corrupted software in the anti-tamper device or the receiving module may cause invalid data interpretation.
In rare cases, the module that interprets the data may have an internal fault, but this is the least likely cause and should only be considered after all other possibilities are ruled out.
It is a sensor or module that detects unauthorized access or tampering with the radiator or cooling system, often used to prevent emissions system modifications or theft of cooling system components.
In most cases, the vehicle will drive normally, but the code may indicate a security or emissions system issue. It is advisable to have it diagnosed promptly to avoid potential limp mode or other restrictions.
Clearing the code may temporarily turn off the warning light, but if the underlying fault is not repaired, the code will return. The code is a symptom, not the cause.
No. While many drivers are told to replace the PCM for U-codes, the radiator anti-tamper device or its wiring is almost always the root cause. Replacing the PCM without proper diagnosis is rarely effective and should be a last resort.