U0147 — Lost Communication With Gateway "B"

OBD2 code U0147 flags a problem with the vehicle network (CAN bus) communication (lost communication with gateway "B"). Short, gentle driving to a shop is usually possible. Common culprits: corroded connectors, especially in wet areas, a faulty module pulling the bus down, water ingress in harness junctions.

vehicle network

Is it safe to drive?

Drive with caution Depends on what is affected. A single dead convenience module is fine to drive with; loss of communication with engine, braking or steering modules is not. If multiple critical systems drop out, do not drive.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm U0147 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many U0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the vehicle network (CAN bus) communication for damage, corrosion, chafing or poor contact.
Subsystem check Measure resistance between CAN-High and CAN-Low at the OBD port with power off — about 60 Ω is healthy.
Subsystem check Scan all modules: the one that does not respond is either the culprit or downstream of the break.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U0147 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for U0147 (parts and labor, USD, independent shop rates): Repair CAN wiring or connectors: $100–$400; Replace the faulty control module: $300–$1,500; Remove interfering aftermarket device: $0–$150. Overall, fixing U0147 usually costs between $0 and $1,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What are the symptoms of U0147?

Drivers most often notice: multiple warning lights on at once, modules intermittently not communicating with the scanner, intermittent loss of functions (gauges, windows, steering assist), no-start or intermittent starting in some cases.

Will U0147 clear itself?

Sometimes U0147 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

How do I diagnose U0147 myself?

Start with a scan: confirm U0147, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the vehicle network (CAN bus) communication, and verify the suspect component against live data before buying parts.

What is the most common cause of U0147?

The most common causes are: corroded connectors, especially in wet areas, a faulty module pulling the bus down, water ingress in harness junctions.

Is it safe to drive with U0147?

Depends on what is affected. A single dead convenience module is fine to drive with; loss of communication with engine, braking or steering modules is not. If multiple critical systems drop out, do not drive.

What does U0147 mean?

U0147 (Lost Communication With Gateway "B") is stored when self-diagnostics detect abnormal readings or behaviour of the vehicle network (CAN bus) communication. It belongs to the vehicle network category.

To set U0147, the control module compares live readings of the vehicle network (CAN bus) communication against calibrated limits, usually over several drive cycles. Alongside the code it stores a freeze frame — a snapshot of rpm, load, coolant temperature and vehicle speed at the moment of failure. Reading that snapshot first saves diagnostic time.

Common symptoms of U0147

multiple warning lights on at once
modules intermittently not communicating with the scanner
intermittent loss of functions (gauges, windows, steering assist)
no-start or intermittent starting in some cases
random, hard-to-reproduce electrical glitches

What causes U0147?

water ingress in harness junctions
aftermarket equipment interfering with the bus
corroded connectors, especially in wet areas
poor grounds or low battery voltage
a faulty module pulling the bus down

How to diagnose U0147

Connect an OBD2 scanner, confirm U0147 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many U0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Visually inspect the wiring harness and connectors related to the vehicle network (CAN bus) communication for damage, corrosion, chafing or poor contact.
Measure resistance between CAN-High and CAN-Low at the OBD port with power off — about 60 Ω is healthy.
Scan all modules: the one that does not respond is either the culprit or downstream of the break.
Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm U0147 does not return.

How to fix U0147

Start with the cheapest and most common causes before replacing expensive parts:

Repair CAN wiring or connectors — $100–$400
Replace the faulty control module — $300–$1,500
Remove interfering aftermarket device — $0–$150

How much does it cost to fix U0147?

Repair cost depends on which component actually failed. Typical scenarios for U0147 (parts and labor, USD, independent shop rates):

Repair CAN wiring or connectors: $100–$400
Replace the faulty control module: $300–$1,500
Remove interfering aftermarket device: $0–$150

Overall, fixing U0147 usually costs between $0 and $1,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.