U0209

Lost Communication With Seat Control Module B

Q: Is it safe to drive with U0209?

Yes. U0209 affects only power seat adjustment and memory for that seat; it has no effect on the engine, brakes, or steering, so the car starts and drives normally. Repair it to restore the feature.

Q: Can I just clear U0209?

You can clear it, but if the module is still off the bus the code returns almost immediately. Fix the wiring, connector, power/ground, or module first, then clear and confirm the feature works.

Network communication Generic OBD-II Low

What it means

U0209 sets when a module loses data-bus communication with Seat Control Module B — the module that operates power adjustment, memory, and related comfort features for that seat. The engine and safety systems are unaffected, so you can drive normally; only that seat's powered functions go down.

Low

Can I keep driving? Yes — power seat adjustment and memory for that seat stops working, but the engine, brakes, and steering are unaffected, so you can keep driving until it's convenient to repair.

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

Power seat adjustment stops working for that seat
Seat memory positions won't recall
Heated/ventilated seat or powered lumbar (if module-controlled) may not respond
A seat-system warning message may appear

Common causes

Most likely first

Corroded, loose, or damaged connector at the module or an inline body connectorLikely
Chafed, broken, or shorted wiring in the communication (CAN) circuit to the moduleCommon
Loss of switched power or ground to the affected moduleCommon
Water intrusion into a body/door connector or the module itselfLess often
Failed module with an internal faultLess often
A wider data-bus problem pulling the network downLess often

How to diagnose & fix

Work through it in order

Scan every module and note all U-codes first — several codes together point to a bus or gateway fault rather than one module.
Inspect the connector and harness at the module for corrosion, bent pins, water, or chafing.
Confirm the module has good switched power and a clean ground with a multimeter.
Check communication-bus continuity and resistance from the module back to the network.
If wiring and power are good, the module is likely faulty — replace and program/configure it as required.
Clear the code, recheck, and confirm the affected feature works and the code stays gone.

FAQ

Quick answers

Is it safe to drive with U0209?+

Yes. U0209 affects only power seat adjustment and memory for that seat; it has no effect on the engine, brakes, or steering, so the car starts and drives normally. Repair it to restore the feature.

Can I just clear U0209?+

You can clear it, but if the module is still off the bus the code returns almost immediately. Fix the wiring, connector, power/ground, or module first, then clear and confirm the feature works.

Read & clear U0209 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