U0119 — Lost Communication With Fuel Cell Control Module

OBD2 code U0119 flags a problem with the vehicle network (CAN bus) communication (lost communication with fuel cell control module). Short, gentle driving to a shop is usually possible. Common culprits: corroded connectors, especially in wet areas, water ingress in harness junctions, damaged CAN bus wiring or short to power/ground.

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 U0119 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 U0119 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for U0119 (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 U0119 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

Is it safe to drive with U0119?

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 is the most common cause of U0119?

The most common causes are: corroded connectors, especially in wet areas, water ingress in harness junctions, damaged CAN bus wiring or short to power/ground.

What are the symptoms of U0119?

Drivers most often notice: modules intermittently not communicating with the scanner, no-start or intermittent starting in some cases, multiple warning lights on at once, random, hard-to-reproduce electrical glitches.

What does OBD2 code U0119 mean?

How do I diagnose U0119 myself?

Start with a scan: confirm U0119, 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 U0119 mean?

U0119 is logged by the onboard diagnostics when the vehicle network (CAN bus) communication does not behave as expected. The official definition is “Lost Communication With Fuel Cell Control Module”. This is a vehicle network category code.

This code does not appear from a single bad reading: the module must see the fault condition repeat under defined operating conditions before it turns on the warning light. The freeze frame captured with U0119 — engine load, rpm, temperature, speed — tells you exactly when the problem occurs, so reproduce those conditions when testing.

Common symptoms of U0119

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

What causes U0119?

water ingress in harness junctions
poor grounds or low battery voltage
corroded connectors, especially in wet areas
a faulty module pulling the bus down
damaged CAN bus wiring or short to power/ground

How to diagnose U0119

Connect an OBD2 scanner, confirm U0119 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 U0119 does not return.

How to fix U0119

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 U0119?

Repair cost depends on which component actually failed. Typical scenarios for U0119 (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 U0119 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.