U0147

Lost Communication With Gateway B

U0147 is a generic OBD-II network diagnostic trouble code: Lost Communication With Gateway B. It is logged by the engine control unit when the network monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
U0147
Group
Network
System
Network
Severity
Warning (MIL on)
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What U0147 means

U0147 indicates that a master gateway or another networked module cannot receive expected serial data messages from the Body Control Module designated 'D'. Vehicles with multiple BCM nodes -- common on larger trucks, full-size SUVs, and luxury platforms -- distribute body electrical functions across several modules labelled A through D or beyond. Module D typically governs a specific sub-set of body functions such as rear lighting, trailer interface, or a particular door or liftgate zone.

The diagnostic approach must first determine which physical BCM-D node the manufacturer has defined for the vehicle being diagnosed, using vehicle-specific wiring diagrams. Without that context, generic J2012 definitions alone cannot identify the affected circuit. Once the module is located, the standard network fault procedure applies: verify power and ground, inspect the harness, and test bus integrity before considering module replacement.

Because BCM-D manages body functions, active symptoms may include inoperative lights, locks, or accessory circuits governed by that module. The MIL or a body-system warning indicator will typically illuminate. Powertrain operation is generally unaffected unless BCM-D feeds inputs (such as a trailer brake controller or rear park sensors) that interact with powertrain control.

Common causes

Most-frequently reported root causes when U0147 is logged.

  • 1
    Open circuit in the CAN bus wiring to the BCM-D node.
  • 2
    Short to ground or short to voltage on the bus segment serving BCM-D.
  • 3
    Corroded or backed-out terminal at the BCM-D connector.
  • 4
    Missing or intermittent ignition or battery power supply to BCM-D.
  • 5
    BCM-D internal hardware failure.
  • 6
    Incorrect programming or missing configuration after a module replacement.
  • 7
    Wiring damage in the area served by BCM-D (e.g., rear body, cargo area, or trailer socket).

Symptoms drivers notice

MIL or body warning lamp illuminated.
Inoperative rear lighting, power locks, or accessory circuits managed by BCM-D.
Trailer interface or towing functions non-operational on equipped vehicles.
Multiple body-system DTCs may be stored if BCM-D inputs are shared across the network.

How to diagnose U0147

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all DTCs and freeze-frame; note whether additional U-codes suggest a wider bus fault.
  2. 2
    Identify the specific BCM-D location and function assignment from the vehicle service manual.
  3. 3
    Measure supply voltage and ground at the BCM-D connector with ignition on.
  4. 4
    Inspect the BCM-D harness for physical damage, particularly in areas prone to moisture or chafing.
  5. 5
    Verify CAN bus termination resistance is within specification on the network segment serving BCM-D.
  6. 6
    Use a scan tool to confirm whether BCM-D is visible on the bus; attempt to communicate with the module directly.
  7. 7
    If all circuits are confirmed good and BCM-D is absent from the bus, replace and program the module per manufacturer procedure.

Related network codes

Frequently asked questions

What functions does BCM-D typically control?

The specific functions vary by manufacturer, but BCM-D often handles rear-zone body electronics such as tail lamps, liftgate, rear HVAC controls, or trailer wiring interface. Consult the vehicle's service documentation for the exact assignment.

Can U0147 be set by a programming error after BCM-D replacement?

Yes. A replacement BCM-D that has not been programmed with the correct vehicle configuration may not communicate properly on the bus, setting U0147 even though the hardware is undamaged.

How do I know if BCM-D is on a separate CAN bus segment?

The vehicle's network topology diagram will show which bus (high-speed CAN, low-speed CAN, LIN, etc.) each BCM node uses. This determines where to check termination resistance and where to look for bus faults.

Could a trailer wiring short cause U0147?

Potentially, if a short on the trailer connector pulls down the supply or bus line feeding BCM-D. Disconnecting the trailer and clearing the code is a reasonable first step when U0147 appears after towing.

Disabling U0147 in software

RaceTune can permanently disable U0147 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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