What it means
Open circuit on the input power line A of the control module. The module is missing or losing its main supply on this rail.
At a glance
- Usually lights the warning light of the system that lost communication
- The engine or gearbox may go into limp mode
How it works
Control Module Input Power A is one of the module's designated supply circuits. U3006 indicates that this input is open or not reaching the module, which can make that module stop operating and trigger warnings or loss of its functions.
Common causes
Most likely first.
- Supply fuse blown
- Power wiring break
- 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 to identify the module reporting U3006 and check freeze-frame or event data for other power-supply faults.
- Inspect the relevant fuse and the module's Input Power A wiring and connectors for a blown fuse, loose terminal, corrosion, or damage.
- Check for battery voltage at the fuse and at the module's Input Power A terminal under the conditions specified by the manufacturer.
- Test continuity and voltage drop along the Input Power A feed, isolating the circuit as directed by the manufacturer's procedure.
- If the feed and connections pass, check the module ground and confirm whether the module itself is operating before considering replacement.
Common fixes
- Replace a blown fuse after checking the Input Power A circuit for a short or overload.
- Repair a broken or corroded Input Power A wire or connector.
- Restore the module supply by repairing a poor connection at the fuse box or power distribution point.
- Replace the affected module only if its Input Power A supply and grounds meet specification but it remains inoperative.
Can I keep driving?
Because the affected module may shut down, drive only if essential functions such as braking, steering, lighting, and engine control remain normal. Avoid driving if warning lights indicate loss of a safety-related system or if the vehicle enters limp mode.
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.