Fault Code Lookup › Network codes › U3018
U3018 Network · manufacturer code
U3018 fault code: what 3 owners reported
U3018 is a manufacturer-specific network code (network: communication between the car's control modules), so its exact definition belongs to the carmaker and is not in the generic OBD-II list. What it meant in practice is below, from 3 complaints owners filed with NHTSA. Updated November 9, 2026.
- 3owner reports
- 3car models
- 0mention a crash
- 0mention a fire
- 2021–2024model years
Which cars get code U3018?
Every model whose owners mentioned U3018 in a complaint, most reports first. Each year opens that car's full problem report. Popular models collect more reports because more of them are on the road.
Where does U3018 show up?
By brand
- GMC2
- Chevrolet1
Component the owner filed it under
Is there a recall for U3018?
The others concern the component owners file this code under (Engine) on the same cars; they may or may not relate to the code. Recall repairs are free; check your VIN at nhtsa.gov/recalls.
Engine And Engine Cooling: Engine: Hard Parts Internal/Mechanical General Motors LLC (GM) is recalling certain 2021-2024 Cadillac Escalade and Escalade ESV, Chevrolet Silverado 1500, Suburban, and Tahoe, GMC Sierra 1500, Yukon, and Yukon XL vehicles equipped with a 6.2L V8 gas engine. The connecting rod and/or crankshaft engine components may have manufacturing…
2024 GMC Yukon, 2021 GMC Yukon, 2021 Chevrolet Tahoe, 2024 GMC Yukon XL. Full risk and remedy on each car's report.
What happened when owners saw U3018?
3 of the 3 reports, spread across the models above, as the owners wrote them. NHTSA removes names and VINs; long reports are trimmed. CarHooq has not verified individual claims.
As I was driving, the vehicle's air conditioning suddenly began blowing warm/hot air. Moments later, the check engine light and all electronic service stability lights illuminated on the dashboard. Simultaneously, the vehicle suffered a complete loss of electronic brake assist, resulting in an extremely hard brake pedal and a severe reduction in braking power. The vehicle also displayed a "No Drive Mode Available" message. Third-party diagnostic scanning revealed network power codes U3018, U3505, P00FF, and P0700, indicating a total loss of power to the Body Control Module (BCM). This is the second life-threatening incident with this vehicle I have experienced following a previous highway…
…A dealer diagnostic scan recorded numerous "Lost Communication" codes across nearly all control modules, plus control-module input-power codes showing low voltage and power-circuit correlation faults (e.g., U3505, U3018, U3007) and an active loss-of-communication code for the power steering module — consistent with an intermittent loss of electrical power or ground affecting engine control. The engine passed the recall's connecting-rod/crankshaft (PicoScope) inspection, so this is not the recalled bearing failure mode. The vehicle is currently at the dealership and is undrivable. The dealer has ordered a new engine and apparently also a new radiator for reasons unknown. No crash or injury…
This is a Post-Remedy Failure of Recall 25V-274 (GMC 6.2L L87 Engine). Following a full engine replacement performed by the dealer under this safety recall, the vehicle has suffered a catastrophic electrical compromise. The vehicle is currently throwing codes P2534 (Low Ignition Voltage) and U3018 (BCM Communication). Safety Hazards: The vehicle experiences sudden loss of power, engine stalling at highway speeds, and total failure of the exterior turn signals (hyper-flash). The AC system has been disabled by the Body Control Module due to low voltage, creating a hazard in high temperatures. This vehicle fits the exact profile of NHTSA Recall Query RQ26-001 and Engineering Analysis EA25-007…
U3018: questions drivers ask
What does code U3018 mean?
U3018 is a manufacturer-specific network code (network: communication between the car's control modules), so its exact definition depends on the carmaker and is not in the generic OBD-II list. 3 owners reported it to NHTSA, most often for the GMC Yukon (2), Chevrolet Tahoe (1), GMC Yukon XL (1); their reports describe what happened.
Which cars get code U3018 most often?
In NHTSA owner complaints, U3018 is mentioned most for the GMC Yukon (2), Chevrolet Tahoe (1), GMC Yukon XL (1), across 3 models and model years 2021 to 2024. Popular models collect more reports because more of them are on the road.
Is there a recall for code U3018?
No NHTSA recall text names U3018 directly. 1 recall on the cars that report this code concerns the same component owners name most (Engine); they may or may not relate to the code. Check your VIN at nhtsa.gov/recalls.
What should I do if my car shows U3018?
Write down when the code appeared and what the car did (warning lights, loss of power, noises, speed, weather). Check your VIN for open recalls at nhtsa.gov/recalls, ask a dealer or independent workshop to read the stored freeze-frame data before anyone clears the code, and keep the repair order. If the car loses power in traffic, stop driving it. CarHooq does not diagnose: these are owner reports and official recall notices, not repair advice.
How this page was made
CarHooq read the text of every owner complaint filed with NHTSA for 19 US and European brands (model years 2012 onwards) and picked out the diagnostic trouble codes owners wrote down. This page lists every mention of U3018. Manufacturer codes have no public standard definition, so CarHooq shows only what owners reported. Nothing here is a diagnosis. More answers: the fault code FAQ. Data: NHTSA Office of Defects Investigation (public domain), retrieved November 9, 2026. How CarHooq reports are made.
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