Broken, chafed, or corroded wiring in the disable circuit between the control module and the component; Loose or damaged electrical connector at the control module or at the disabled component; Failed control module output driver for the disable circuit; Open relay coil or faulty relay contacts in the disable circuit path; Corrosion or water intrusion in a connector or splice pack along the disable circuit; Aftermarket accessory improperly tapped into the disable circuit, creating an open or high resistance; Internal open circuit in the component being disabled, such as a solenoid or actuator

DTC codes / U30xx · Network wiring and bus faults / U3025

U3025Control Module A Disable Circuit/Open

Q: What does code U3025 mean?

Control Module A Disable Circuit/Open. U3025 indicates that a control module responsible for enabling or disabling a subsystem has detected an open circuit or a fault in the disable circuit itself. The module monitors the voltage or current on the disable line and sets this code when the expected signal is missing or out of range, preventing the subsystem from being turned off when required.

U3025 indicates that a control module responsible for enabling or disabling a subsystem has detected an open circuit or a fault in the disable circuit itself. The module monitors the voltage or current on the disable line and sets this code when the expected signal is missing or out of range, preventing the subsystem from being turned off when required.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaNetwork wiring and bus faults

Symptoms you may notice

Illumination of the malfunction indicator lamp (MIL) on the dashboard
Often no symptoms besides the warning light, as the disable function may not affect normal operation
The associated subsystem may remain active when it should be disabled, such as a pump or motor that continues to run
Intermittent operation of the affected system if the open circuit is temperature or vibration sensitive
Other modules may log communication or performance codes if the disable circuit is shared with a network
Possible battery drain if the disable circuit failure keeps a component energized after shutdown

Common causes, most likely first

Broken, chafed, or corroded wiring in the disable circuit between the control module and the component
Loose or damaged electrical connector at the control module or at the disabled component
Failed control module output driver for the disable circuit
Open relay coil or faulty relay contacts in the disable circuit path
Corrosion or water intrusion in a connector or splice pack along the disable circuit
Aftermarket accessory improperly tapped into the disable circuit, creating an open or high resistance
Internal open circuit in the component being disabled, such as a solenoid or actuator

How to diagnose and fix it

Connect a scan tool and record all stored codes, then clear codes and verify whether U3025 returns immediately or after a drive cycle
Obtain the factory wiring diagram for the disable circuit and identify all connectors, splices, and relays between the control module and the component
Perform a visual inspection of the disable circuit wiring for chafing, corrosion, loose pins, and signs of rodent damage
Use a digital multimeter to check continuity and resistance on the disable circuit with the module disconnected, looking for an open or excessive resistance
Backprobe the control module connector and monitor the disable circuit voltage while commanding the component on and off with the scan tool
Test the disable relay by swapping it with a known-good identical relay or by measuring coil resistance and contact continuity
If wiring and relays test good, substitute a known-good control module or perform a module relearn procedure as required by the manufacturer

What the disable circuit really does

Many technicians replace the control module first, but an open circuit in the disable wire or a corroded connector is far more common than a failed module driver.
The disable circuit often carries only a low-current signal, so a high-resistance connection that looks fine visually can still set U3025 intermittently.
A relay that has failed open in the disable path will mimic a module fault, so always test the relay before condemning the module.
Aftermarket alarms, remote starters, or kill switches tapped into the disable circuit are a frequent cause of U3025 that owners forget to mention.
On some vehicles the disable circuit is shared with a network segment, so a single open can set communication codes in other modules alongside U3025.

Can I keep driving with U3025?

The vehicle is generally safe to drive because the disable function usually affects a non-critical subsystem, but avoid relying on the affected system being disabled and address the fault promptly to prevent battery drain or unintended operation. If the code is accompanied by drivability symptoms or multiple communication codes, have it diagnosed before extended driving.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.