What does it mean?
C1271 is a Chassis (ABS, traction control, steering) fault code. It indicates: RF Speed Output . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- ABS, traction and stability lamps on and those systems disabled
- Speedometer erratic or dropping to zero on vehicles that take the signal from this circuit
- ABS activating at very low speed or the pedal pulsing when it should not
- Cruise control unavailable
- Transmission shift quality or four wheel drive behaviour may change on vehicles that share this signal
Likely causes
- Faulty right front wheel speed sensor or a damaged sensing tip
- Rust, debris or missing teeth on the right front reluctor (tone) ring
- Excessive wheel bearing play changing the air gap as the wheel turns
- Chafed, cut or corroded sensor harness at the strut, wheel liner or brake hose bracket
- Corroded connector behind the wheel arch where water collects
- Fault in the wheel speed output circuit between the ABS module and the module that uses the signal
- Failed output driver inside the ABS control module
How to fix it
- Drive the vehicle while watching all four wheel speeds in live data; the affected corner drops out or reads zero
- Inspect the right front sensor, harness and connector for cuts, rodent damage and corrosion
- Remove the sensor, clean the mounting bore and the tip, and check the tone ring for rust, cracks and missing teeth
- Check the wheel bearing for play, since a loose bearing produces an intermittent signal
- Measure sensor resistance or output as appropriate for the sensor type and test the circuit for open and short
- Verify continuity of the output circuit between the ABS module and the module reporting the missing signal
- Replace the sensor, tone ring or hub assembly according to what the tests show, then clear the codes and road test