OBD2 Car ScannerWhat does C1234 mean?
C1234 stands for Speed Wheel RF Input Signal Missing. A chassis module has found a fault in a system like ABS, traction or stability control, steering or suspension.
Chassis codes cover the ABS, traction control, steering and suspension. When the car's computer sees a reading outside its normal range, it stores this code and may turn on a warning light on the dashboard.
Common causes
- Faulty or dirty wheel speed sensor
- Damaged sensor wiring
- Low brake fluid
- Faulty ABS pump or module
What to do
- Read all stored and pending codes with a scanner. Several codes together often point to one cause.
- Note the freeze frame data (speed, temperature, load) recorded when the code was set.
- Inspect the wiring and connectors of the part named in the code for damage, corrosion or looseness.
- Fix the most likely and cheapest cause first, then clear the code and drive to see if it comes back.
Read this code from your own car
Plug in a cheap ELM327 adapter and the app shows every fault code, what it means and how to fix it.
Frequently asked questions
What does C1234 mean?
C1234 means “Speed Wheel RF Input Signal Missing”. It belongs to the chassis system group: A chassis module has found a fault in a system like ABS, traction or stability control, steering or suspension.
Is it safe to drive with C1234?
Avoid driving long distances. This kind of fault can cause damage or affect safety, so get it checked as soon as possible.
How do I clear C1234?
Fix the cause, then clear the code with an OBD2 scanner or app. If the fault is still there, the code will come back.
Related codes
- C1230Speed Wheel Sensor Rear Center Input Circuit Failure
- C1231Speed Wheel Sensor Rear Center Circuit Open
- C1232Speed Wheel Sensor Rear Center Input Short Circuit To Battery
- C1233Speed Wheel LF Input Signal Missing
- C1235Speed Wheel RR Input Signal Missing
- C1236Speed Wheel LR Input Signal Missing
- C1237Speed Wheel Rear Input Signal Missing
- C1238ABS Hydraulic Pressure Differential Switch Input Circuit Failure
Code meanings can vary by manufacturer. This page is general guidance, not a repair manual. Always confirm the cause before replacing parts.