Blown fuse or tripped circuit breaker supplying the module's D power circuit; Corroded, loose, or damaged power wire terminal at the module connector; Open circuit in the power wire between the fuse box and the module, often due to chafing or rodent damage; Faulty power relay that feeds the D circuit; Poor ground connection at the module or chassis, causing the module to sense low voltage on its power input; Internal fault in the module causing it to draw excessive current and blow the fuse; Water intrusion into the module connector or fuse box causing corrosion and high resistance

DTC codes / U30xx · Network wiring and bus faults / U3014

U3014Control Module Input Power D Circuit/Open

Q: What does code U3014 mean?

Control Module Input Power D Circuit/Open. U3014 is a generic network communication code indicating that a control module has detected an open circuit or loss of power on the dedicated input power circuit designated as 'D' for that module. The module itself is not necessarily faulty; the code means the module's power feed is missing or intermittent, so the module cannot operate reliably and may drop off the network.

U3014 is a generic network communication code indicating that a control module has detected an open circuit or loss of power on the dedicated input power circuit designated as 'D' for that module. The module itself is not necessarily faulty; the code means the module's power feed is missing or intermittent, so the module cannot operate reliably and may drop off the network.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaNetwork wiring and bus faults

Symptoms you may notice

Illumination of the check engine light or a module-specific warning lamp
One or more electrical systems controlled by the affected module may stop working or behave erratically
Intermittent no-start or stalling if the module involved is the engine control module (ECM) or body control module (BCM)
Communication loss with scan tools or other modules on the network
Often no symptoms besides the warning light if the module has a redundant power feed

Common causes, most likely first

Blown fuse or tripped circuit breaker supplying the module's D power circuit
Corroded, loose, or damaged power wire terminal at the module connector
Open circuit in the power wire between the fuse box and the module, often due to chafing or rodent damage
Faulty power relay that feeds the D circuit
Poor ground connection at the module or chassis, causing the module to sense low voltage on its power input
Internal fault in the module causing it to draw excessive current and blow the fuse
Water intrusion into the module connector or fuse box causing corrosion and high resistance

How to diagnose and fix it

Verify the code with a scan tool and record all stored and pending codes before clearing anything
Locate the fuse and relay for the affected module's D power circuit using the vehicle's service information and inspect them for continuity
Disconnect the module connector and check for battery voltage on the D power circuit terminal with the key on
Perform a voltage drop test on the power wire and ground circuit to identify excessive resistance under load
Inspect the wiring harness for chafing, corrosion, or rodent damage along the route from the fuse box to the module
If power and ground are good, substitute a known-good module or perform a bench test to rule out an internal module fault
Repair the open circuit, replace the faulty fuse, relay, or module, then clear codes and verify the module communicates and the code does not return

What the D circuit really tells you

U3014 often appears after battery replacement or jump-starting because voltage spikes can blow the module's power fuse, leading people to replace the module unnecessarily.
A module can set this code even when it still powers up on a secondary feed, so the vehicle may run fine and the only clue is the stored code.
Corrosion inside a connector pin is a common cause that a simple fuse check misses; always inspect the terminal tension and look for green or white deposits.
The D circuit designation is module-specific, so the same code on different vehicles may point to completely different fuses and wire colors; never assume a universal location.
A weak battery or failing alternator can cause modules to log U3014 intermittently because the module sees low voltage during cranking and interprets it as an open circuit.

Can I keep driving with U3014?

If the vehicle starts and runs normally, you can drive it to a repair shop, but avoid long trips and heavy electrical loads until the fault is fixed. If the engine stalls, will not start, or multiple warning lights are on, stop driving and have the vehicle towed to prevent safety-system failures.

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.