U3006

Code

HYUNDAI U — Network/User

Control Module Input Power “A”

Brand: HYUNDAI

Type: U — Network/User

Views: UK: 13 EN: 23 RU: 12

AI status

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Page language: EN

Causes

Blown fuse or tripped circuit breaker supplying the module power rail
Open or short in the module power (Input Power A) wiring
Poor or corroded battery, chassis or engine ground connections
Low battery voltage or weak battery (especially during cranking)
Faulty power relay supplying the module
Intermittent connector pin contact (corrosion, loose terminal, bent pin)

Symptoms

Check Engine / MIL or other warning lights illuminated
Loss or intermittent operation of systems controlled by the affected module (doors, lighting, HVAC, instrument cluster, etc.)
No communication with the module on the diagnostic tool (module not responding)
Intermittent electrical faults or flickering dashboard instruments
Vehicle may fail to start or experience hard start if module is critical to starting
Multiple related DTCs set from modules that lost communication

What to check

Use a scan tool: read U3006 code, stored freeze-frame and related codes, check module response on bus
Check vehicle battery voltage (key OFF, key ON, during cranking)
Inspect and test fuses and relays related to the suspect module power rail
Visually inspect module connector(s) for corrosion, bent pins or water intrusion
Measure voltage at the module power pin (Input Power A) with key ON and cranking
Verify good chassis and engine grounds near module and battery

Signal parameters

Battery voltage (key OFF, resting): ~12.3–12.8 V (vehicle dependent)
Battery voltage (key ON, engine off): should be within ~0–0.5 V of battery resting voltage; generally 11.5–14.5 V
Cranking voltage: typically not below ~9.5–10.5 V (manufacturer specific limits apply)
Module supply pin (Input Power A): expected ≈ battery voltage when key ON/Run (within ±0.5 V)
Module ground: continuity to battery negative near 0 Ω to a few ohms; high resistance indicates problem
CAN/communication line idle voltages: approx. 2.5 V on each bus line (differential ~0 V) and proper termination

Diagnostic algorithm

Retrieve DTCs and freeze-frame data with a capable scan tool. Note conditions when U3006 set (key state, engine running, mileage, temp).
Inspect fuses and relays for the module power feed. Replace suspect fuses/relays and retest.
Measure battery voltage at battery terminals and at module power pin (Input Power A) with key OFF, key ON, and during crank. Compare readings.
Inspect module connector for corrosion, water intrusion, damaged wires or pushed-out pins. Repair or replace connector as needed.
Check all module grounds for tightness and corrosion; clean and retighten ground straps and bolts.
Perform a wiring continuity and resistance check from the fuse/relay output to the module power pin; look for opens, shorts to ground or battery, or high resistance.
If intermittent, wiggle harness and connectors while monitoring voltage/communication to reproduce fault.
Check for aftermarket installations or recent repairs that may have altered the power circuit; correct any improper splices or loads.
If supply wiring and external systems test good, suspect internal module power regulator failure. Verify with manufacturer-specific tests or replace/module reprogram as directed by service manual.
After repairs, clear codes and road-test under the same conditions. Confirm U3006 does not return and related functions are restored.

Likely causes

Blown fuse or failed power relay on the module’s A supply
Loose, corroded, or damaged connector at the affected control module
Low battery or poor main ground reducing voltage at the module
Short to ground or high resistance in the feed wire to the module
Module internal power supply/regulator failure (less common)

Fault status

⚠️ Status

Control module reported abnormal Input Power A: supply voltage missing, low, intermittent, or out of expected range. Check power feed, fuses/relays, grounds, connector integrity, battery condition and wiring before replacing the module.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 3.0 hours

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U3006 — Control Module Input Power “A”