U0426

Invalid Data Received From Vehicle Immobilizer Control Module

Communication network Generic OBD-II Medium

What it means

U0426 is a network communication code: a module is receiving data from the vehicle immobilizer control module that is corrupt, missing, or out of range. The immobilizer is the anti-theft system that validates your key before allowing the engine to run. Because of that role, invalid data can prevent the vehicle from starting, so this code carries a real risk of being stranded even though it's not an engine fault.

Medium

Can I keep driving? May not start — if the immobilizer can't validate the key, the engine can be prevented from starting, leaving you stranded.

Real-world scan data

Seen in

358

scans in the past year

Found in

0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of U0426 scans

P0683in 38.8% of scans

P0110in 30.4% of scans

P0704in 29.9% 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

Engine cranks but won't start, or won't crank at all
Immobilizer, key, or security warning light on
Key not recognized intermittently
Other security or network warning lights at the same time

Common causes

Most likely first

Internal fault in the immobilizer control module sending corrupt dataLikely
Wiring or connector problems on the bus to the immobilizer moduleCommon
Low system voltage or a poor ground disrupting immobilizer communicationCommon
Failed key, key antenna/transponder ring, or a mismatched key after serviceLess often

How to diagnose & fix

Work through it in order

Scan all modules and record freeze-frame data; address lost-communication codes first.
Check battery voltage and grounds — weak power often disrupts immobilizer data.
Inspect the immobilizer module connector and bus wiring for corrosion or loose pins.
Test the key antenna/transponder ring and try a known-good key.
If wiring and power are good, suspect the immobilizer module; reprogram or replace and re-learn keys per manufacturer procedure.

FAQ

Quick answers

Is it safe to drive with U0426?+

Driving is fine while it runs, but the risk is being unable to restart if the immobilizer stops validating the key. Get it diagnosed before you're stranded somewhere inconvenient.

Can I just clear U0426?+

Clearing may let it start again briefly, but it returns while the module reports bad data. Because it's anti-theft related, key re-learning may need dealer or specialist tools.

Read & clear U0426 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