U0146

Universal

Lost Communication With Gateway A

Definition source: General OBD-II reference catalog
Definition verification: Not independently verified for display.
Time: Varies by diagnosis and vehicle | Diagnostic difficulty: Medium
Medium Severity

The vehicle has detected that one or more control modules are not communicating with Gateway A. A gateway routes messages between vehicle communication networks, so a communication loss can affect information sharing between systems. The code identifies a detected communication problem, not proof that the gateway itself has failed.

Report an error with this code

⚠️ Before You Begin (Safety First)

If warning lights or communication problems are accompanied by impaired braking, steering, or another safety-critical function, stop driving when it is safe to do so and arrange professional help. Otherwise, have the fault checked soon, especially if multiple systems are affected.

Common Symptoms

  • There may be no noticeable symptoms if the communication loss is intermittent or does not affect a system the driver is using.
  • Warning lights or communication messages may appear if information from affected modules is unavailable.
  • Some vehicle features may work incorrectly or become unavailable when the modules controlling them cannot exchange messages through the gateway.
  • Multiple communication-related fault codes may be stored if several modules lose contact or share a network problem.

Common Causes

  • A loose, damaged, or corroded connector or network wire may interrupt communication.
  • A fuse, power supply, or ground problem affecting the gateway or a connected module may prevent communication.
  • A fault elsewhere on a vehicle communication network may disrupt messages passing through the gateway.
  • Low or unstable vehicle voltage may contribute to temporary communication loss.
  • The gateway or another control module may have an internal fault, but testing is needed before identifying a failed module.

Diagnostic Steps

  1. Note any warning messages, unusual feature behavior, or recent battery or electrical work; this context can help narrow down an intermittent communication issue.
  2. With the vehicle safely parked and switched off, visually check accessible gateway-related wiring and connectors for looseness, damage, or corrosion. Do not probe connectors or disturb safety-system wiring.
  3. Check the owner's manual for fuses associated with relevant modules or communication systems, and inspect them only as directed. Replace a fuse only with the specified type and rating; if it blows again, seek diagnosis.
  4. If you have a suitable scan tool, record codes from all accessible modules before clearing anything. Several related codes can help distinguish a gateway-specific issue from a wider network or power problem.
  5. If the code returns, multiple systems are affected, or the gateway cannot be safely identified, have a qualified technician perform model-specific network and electrical tests.

When to Call a Professional

A technician can scan all available modules, compare which modules are and are not communicating, and check related network codes. They can then inspect the gateway's power, ground, connectors, and network wiring using model-specific service information before deciding whether a module needs repair or replacement.

Compare component listings

Confirm diagnosis and vehicle fitment before buying. A listing does not prove that a part needs replacement. We may earn a commission from qualifying purchases.

Search Amazon Search eBay

Commonly Asked Questions

Does U0146 prove that Gateway A needs replacement?

No. The code reports lost communication with Gateway A. Wiring, connectors, power, ground, vehicle voltage, another network fault, or a module problem can cause a similar communication loss.

Can the vehicle still be driven with this code?

It depends on which functions are affected. If braking, steering, or another safety-critical function is impaired, stop driving when safe and arrange professional help. If there are no symptoms, arrange diagnosis soon because the affected systems can vary by vehicle.

Why are there several communication codes at once?

Multiple codes can occur when several modules lose messages because of a shared network, power, or ground issue. A full-module scan helps establish which modules are affected and which codes may be secondary.

Should I clear the code and see whether it returns?

Record codes from all accessible modules first. Clearing them without recording the surrounding information can remove useful diagnostic clues; a technician can advise whether clearing is appropriate after the data is saved.

Browse Available Code Guides

Previous and next available guides in database record order, across makes. Adjacent entries may share a code number and do not necessarily describe related faults.