What does it mean?
U3006 is a Network (CAN bus, module communications) fault code. It indicates: Control Module Input Power "A" . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- The system controlled by that module is completely dead
- Warning lamps for that system on the cluster
- Scan tool cannot communicate with the module
- Repeated fuse failures on that circuit
- The vehicle may not start if the module sits in the starting path
- The code sets again at every key-on
Likely causes
- Blown fuse feeding the module's "A" power input
- Open circuit or a broken conductor between the fuse box and the module
- Corroded, burnt or pushed-back terminal at the module connector or in the fuse box
- Failed relay supplying that circuit
- Worn ignition switch contacts on a switched power feed
- Wiring damage after accessory fitment, bodywork or rodent activity
- Internal module fault loading the feed until the circuit opens
How to fix it
- Identify which fuse and relay feed the module's "A" power input from the wiring information
- Check the fuse visually and with a test lamp while the circuit is live
- Measure voltage at the module connector pin with the key on, then repeat as a voltage drop test under load
- Check continuity from the fuse box to the module with the circuit disconnected
- Swap or bench-test the relay that supplies the circuit
- Inspect the connector for burnt, spread or pushed-back terminals and repair them properly
- Replace the module only after a steady, correct supply is confirmed at its connector