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U3006 — Control Module Input Power Circuitopen

Manufacturer-specificNetwork / communication

Code U3006 indicates that a specific control module has lost its input power supply. The 'open circuit' means there is a break in the electrical path, preventing the module from receiving the voltage necessary to operate.

Symptoms

What causes it — most likely first

1. Blown Fuse

The most common cause is a blown fuse in the power distribution block that supplies the module.

2. Corroded Connectors

Moisture or contaminants in the module connector can cause high resistance or a complete break in the circuit.

3. Damaged Wiring

Wires may be frayed, pinched, or severed due to mechanical wear or rodent damage.

4. Faulty Power Relay

A failed relay may prevent power from being routed to the control module.

5. Internal Module Failure

The control module itself may have an internal short or open circuit that disrupts power input.

6. PCM/ECM Power Circuit Failure

A failure within the main engine computer's power distribution logic, though this is rare compared to wiring faults.

How it's diagnosed

  1. Identify the specific control module associated with the U3006 code using a scan tool.
  2. Inspect the relevant fuses for continuity or visible breaks.
  3. Perform a voltage test at the module's input pin using a digital multimeter to verify if power is reaching the component.
  4. Visually inspect the wiring harness for signs of chafing, burning, or breaks.
  5. Check the ground circuit for the module to ensure the circuit is properly completed.
  6. Test the operation of the power relay associated with the module's circuit.

Code facts & related codes

SystemNetwork / communication
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Does a U3006 code mean I need to replace the PCM?

Usually no. This code typically indicates a power delivery problem, such as a blown fuse or broken wire, rather than a failure of the PCM itself.

Can low battery voltage trigger this code?

While low voltage can cause communication issues, U3006 specifically denotes an 'open' circuit, meaning the electrical path is physically interrupted.

Is it safe to drive with this code?

It depends on which module is affected. If it is a critical system like the airbags or braking, the vehicle may be unsafe; if it is a convenience module, the vehicle may remain drivable but with lost features.