U0233

Lost Communication With Side Obstacle Detection Control Module B

Q: Is it safe to drive with U0233?

Mechanically yes — the engine and transmission are unaffected. But blind-spot / side obstacle monitoring won't work, so don't rely on it and get the wiring checked.

Q: Can I just clear U0233?

You can, but if the module is still off the bus the code returns within a few drive cycles. Fix the wiring or power fault first.

Communication network Generic OBD-II Low

What it means

U0233 means the network has lost communication with side obstacle detection control module 'B' — the second blind-spot / side-obstacle monitor (typically the opposite side from module A). The vehicle drives normally, but that side's blind-spot alerts stop working.

Low

Can I keep driving? Yes — the car drives normally, but blind-spot and side-obstacle alerts are disabled, so check your mirrors and get it fixed.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

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

Blind-spot / side obstacle monitoring stops working or shows a 'system unavailable' message
A warning light for the feature (or the check-engine light) comes on
Blind-spot indicators on one side stay off
The affected module doesn't respond on a full-system scan

Common causes

Most likely first

Damaged wiring or a loose/corroded connector at the module (often in a rear quarter-panel or bumper)Likely
Loss of power or ground to the moduleCommon
A CAN bus fault (open, short, or high resistance) on that circuitCommon
Water intrusion or corrosion at the module or its connectorLess often
Failed module (least common — rule out wiring and power first)Less often

How to diagnose & fix

Work through it in order

Scan all modules and note exactly which one reports the code to locate the affected segment.
Inspect the wiring and connector at the module (often in a rear quarter-panel or bumper) for damage, chafing, or corrosion.
Check power and ground to the module with the connector loaded.
Test the CAN bus circuits to the module for opens, shorts, or high resistance.
If wiring and power test good, suspect the module itself. Repair and re-test.

FAQ

Quick answers

Is it safe to drive with U0233?+

Mechanically yes — the engine and transmission are unaffected. But blind-spot / side obstacle monitoring won't work, so don't rely on it and get the wiring checked.

Can I just clear U0233?+

You can, but if the module is still off the bus the code returns within a few drive cycles. Fix the wiring or power fault first.

Read & clear U0233 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