C1234: Right Front Wheel Speed Sensor Input Signal Missing
2 vehicles · 2 makes · $250-$700 repair
Most Reported On
C1234 is an OBD-II diagnostic trouble code meaning “Right Front Wheel Speed Sensor Input Signal Missing.” This code indicates the ABS control module is not receiving a valid speed signal from the right front wheel speed sensor. These sensors report individual wheel speeds, and the data is required for anti-lock braking, traction control, and stability control to function. When the signal is missing, the module disables those safety systems as a fail-safe and illuminates the ABS and related warning lights. Normal hydraulic braking still works, but ABS and stability assistance are lost. This code is most commonly reported on 2021-2024 Kia K5, and 2002-2010 Ford Explorer, with repair costs ranging from $250 to $700.
Common Causes
Typical Repair Cost
Based on 2 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose C1234, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
FAQ
What does C1234 mean?
C1234 stands for "Right Front Wheel Speed Sensor Input Signal Missing." This code indicates the ABS control module is not receiving a valid speed signal from the right front wheel speed sensor. These sensors report individual wheel speeds, and the data is required for anti-lock braking, traction control, and stability control to function. When the signal is missing, the module disables those safety systems as a fail-safe and illuminates the ABS and related warning lights. Normal hydraulic braking still works, but ABS and stability assistance are lost.
What are the most common causes of C1234?
The most common causes of C1234 are: Faulty right front wheel speed sensor, Damaged sensor wiring or connector, Cracked or damaged tone/reluctor ring, Debris or metal contamination on the sensor tip, Corrosion at the connector, Wheel bearing with integrated sensor failure, ABS module fault (less common). The specific cause varies by vehicle.
How much does it cost to fix C1234?
Repair costs for C1234 range from $250 to $700, depending on the vehicle and root cause.
Which vehicles are affected by C1234?
Au7o has documented C1234 across 2 vehicle models from 2 manufacturers: Ford, Kia.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.