U0406

Invalid Data Received From Fuel Injector Control Module

Q: 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.

Q: 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.

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.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Appears alongside · share of U0406 scans

P0406in 100.0% of scans

P0487in 93.6% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

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.

Read & clear U0406 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX