Lost Communication With Restraints System Sensor B
U0171 is an OBD-II trouble code that indicates lost communication with restraints system sensor b. This page explains what the code means, what issues may trigger it, common symptoms and where to look next.
U0171 code meaning is one of the most common OBD-II searches when a warning light appears on the dashboard.
Drivers searching for U0171 usually want to know what the code means, whether the car is safe to drive and what part may need testing first.
Likely causes
- • Faulty sensor
- • Damaged sensor wiring
- • Loose or corroded connector
- • Wiring or connector issue
- • Component failure in the affected system
- • Intermittent signal or control fault
Symptoms
- • Check engine light illuminated
- • Intermittent warning light
- • Inconsistent engine performance
Severity
Low to Medium
Can you keep driving?
Whether you can keep driving depends on how the vehicle is behaving. If there is rough running, loss of power, overheating or stalling, diagnose it as soon as possible.
Common fix areas
- • Verify live data and sensor voltage
- • Inspect sensor connector and wiring
- • Scan all fault codes and freeze-frame data
- • Inspect wiring, connectors and grounds
- • Confirm repair with a retest after clearing codes
Manufacturer notes
FAQs
What does U0171 mean?
U0171 means lost communication with restraints system sensor b.
What can cause U0171?
Common causes include component failure, wiring faults, incorrect sensor readings, leaks, pressure issues or related upstream faults in the same system.
Can I keep driving with U0171?
That depends on how the car is behaving. If there is rough running, overheating, loss of power or stalling, it should be diagnosed quickly.
Does U0171 always mean I need a new part?
No. A fault code points you to a system or condition, but proper diagnosis is still needed before replacing parts.