U0047 — Vehicle Communication Bus C Performance
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 U0047 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 U0047 does not return.
Approximate repair cost
Repair cost depends on which component actually failed. Typical scenarios for U0047 (parts and labor, USD, independent shop rates): Remove interfering aftermarket device: $0–$150; Replace the faulty control module: $300–$1,500; Repair CAN wiring or connectors: $100–$400. Overall, fixing U0047 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 is the most common cause of U0047?
The most common causes are: water ingress in harness junctions, damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas.
How much does it cost to fix U0047?
Remove interfering aftermarket device — $0–$150; Replace the faulty control module — $300–$1,500; Repair CAN wiring or connectors — $100–$400. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.
What are the symptoms of U0047?
Drivers most often notice: multiple warning lights on at once, random, hard-to-reproduce electrical glitches, intermittent loss of functions (gauges, windows, steering assist), no-start or intermittent starting in some cases.
How do I diagnose U0047 myself?
Start with a scan: confirm U0047, 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 does OBD2 code U0047 mean?
Vehicle Communication Bus C Performance (U0047): a vehicle network fault affecting the vehicle network (CAN bus) communication. Short, gentle driving to a shop is usually possible. Most often caused by water ingress in harness junctions, damaged CAN bus wiring or short to power/ground, corroded connectors, especially in wet areas.
What does U0047 mean?
The engine control module sets U0047 when it detects a fault in the vehicle network (CAN bus) communication. In practical terms: vehicle communication bus c performance. The code belongs to the vehicle network group of OBD2 codes.
The module monitors this system continuously while driving. When readings fall outside the expected range for a defined number of drive cycles, it stores U0047 and switches on the warning light. Freeze frame data saved with the code shows the exact conditions — rpm, load, temperature, speed — at the moment the fault was detected, which is the best starting point for diagnosis.
What causes U0047?
- corroded connectors, especially in wet areas
- a faulty module pulling the bus down
- damaged CAN bus wiring or short to power/ground
- poor grounds or low battery voltage
Common symptoms of U0047
- multiple warning lights on at once
- random, hard-to-reproduce electrical glitches
- intermittent loss of functions (gauges, windows, steering assist)
- no-start or intermittent starting in some cases
- modules intermittently not communicating with the scanner
How to diagnose U0047
- Connect an OBD2 scanner, confirm U0047 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 U0047 does not return.
How to fix U0047
Start with the cheapest and most common causes before replacing expensive parts:
- Remove interfering aftermarket device — $0–$150
- Replace the faulty control module — $300–$1,500
- Repair CAN wiring or connectors — $100–$400
How much does it cost to fix U0047?
Repair cost depends on which component actually failed. Typical scenarios for U0047 (parts and labor, USD, independent shop rates):
- Remove interfering aftermarket device: $0–$150
- Replace the faulty control module: $300–$1,500
- Repair CAN wiring or connectors: $100–$400
Overall, fixing U0047 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.
Can you drive with U0047?
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.