U0406
Invalid Data Received From Fuel Injector Control Module
Communication network (fuel injection)
Generic OBD-II
High
What it means
U0406 sets when a control module reads data from the fuel injector control module that is missing, out of range, or implausible. Because this module governs how fuel is delivered to the cylinders, bad data can make the engine run poorly, drop into limp mode, and in some cases stall or refuse to start.
High
Can I keep driving? Risky — the engine can run rough, drop into limp mode, or even stall or fail to start, so drive as little as possible until it's diagnosed.
Common symptoms
What you'll notice
- Check-engine light on, often with a reduced-power or fuel-system warning
- Rough running, hesitation, or a misfire-like stumble
- Hard starting or, in some cases, a no-start
- Engine drops into limp (reduced-power) mode
- Related communication codes stored in other modules
Common causes
Most likely first
- Faulty fuel injector control module or its power/ground supplyLikely
- Corroded, loose, or damaged connectors and data-bus (CAN) wiringCommon
- Low or unstable battery and charging-system voltageCommon
- Software incompatibility after a module was replaced or updatedLess often
- An underlying fault in the injector circuits the module reports onLess often
How to diagnose & fix
Work through it in order
- Scan every module and record all stored codes and freeze-frame data before clearing anything.
- Check battery and charging voltage — weak or noisy voltage is a common cause of bus data errors.
- Inspect the connectors and wiring to the fuel injector control module and along the data bus for corrosion or damage.
- If a module was recently replaced or flashed, confirm it has the correct, compatible software.
- Follow the manufacturer's pinpoint tests for the module; replace it only after power, grounds, and wiring check out.
FAQ
Quick answers
Is it safe to drive with U0406?+
Not really — this code can come with real drivability problems like rough running, limp mode, or even a no-start, so get it diagnosed before driving far.
Can I just clear U0406?+
You can clear it, but if the fuel injector module or its data link is still faulty the code returns within a few drive cycles.
Related codes
Often seen with U0406
Read & clear U0406 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX