C1148

Code

LAND ROVER C — Chassis

Failure in the front wheel speed sensor input circuit

Brand: LAND ROVER

Type: C — Chassis

Views: UK: 24 EN: 65 RU: 31

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Page language: EN

Causes

Damaged or failed front wheel speed sensor (passive or active type)
Open, shorted or chafed wiring between sensor and ABS module
Corroded, bent or water-intruded connector or pin
Damaged or missing tone/reluctor ring on hub or bearing
Loose or missing sensor mounting / incorrect air gap
Faulty ABS/traction control module or internal input circuit

Symptoms

ABS warning lamp illuminated
Traction control / stability control warning lights
Loss or reduction of ABS/traction control functionality
Possible ABS system warnings during braking (pulsing or no pulse)
Associated fault codes stored for wheel speed sensor input
Occasional inconsistent wheel speed reading on scan tool

What to check

Scan tool: read C1148 and any related ABS/traction codes; view freeze frame and live wheel speed data
Visual inspection of both front wheel speed sensors, tone rings, harness and connectors for damage, corrosion or contamination
Wiggle/connectivity test: backprobe sensor connector while monitoring live data or signal to detect intermittent faults
Measure sensor resistance (for passive sensor) and compare to specification
Check reference supply and ground at sensor connector (typically a 5V reference or battery/ground depending on sensor type)
Check for shorts to power or ground and continuity between sensor connector and ABS module connector

Signal parameters

Passive (magnetic) sensor: DC resistance typically in hundreds to low thousands of ohms (e.g., ~800–1500 Ω) and AC voltage that rises with wheel speed
Active (hall/effect) sensor: reference supply typically ~5 V, signal toggles or varies roughly 0.5–4.5 V depending on design
Signal frequency (both types): increases with wheel speed — expected to be low at walking speed and increase smoothly as wheel rotates
Open-circuit reading: infinite resistance (or OL) for passive sensors indicates open; short-to-ground or short-to-Vb will show low resistance or near 0 Ω
Intermittent signal or dropouts when connector is wiggled indicates wiring/connector fault

Diagnostic algorithm

Retrieve full code list and freeze frame with a professional scan tool. Identify which front sensor (left/right) is referenced and note any related codes.
Perform a visual inspection of the sensor, tone ring and harness routing. Look for broken tone-ring teeth, heavy rust, debris, rubbing harness or damaged insulation.
Backprobe the sensor connector. With ignition ON (engine off) check for expected reference voltage and ground. Record values.
Measure sensor resistance (passive) or check signal with a multimeter/oscilloscope while rotating the wheel. Compare to manufacturer spec. For active sensors, observe signal waveform with oscilloscope while spinning the wheel.
Wiggle test the harness and connector while observing live data or signal. If the signal drops or code returns, repair/replace wiring or connector.
Check continuity from sensor connector to ABS module pin to verify no opens or shorts. Repair any damaged wiring or pins.
If connector and wiring are good, swap the suspect front sensor with the opposite front sensor (if identical) and see if the code follows the sensor — this helps confirm a bad sensor.
Replace the sensor if out of spec, and correct any tone ring or mounting issues (clean, realign, replace damaged tone ring or bearing).
After repairs clear codes and perform a road test to confirm correct wheel speed signals and that the C1148 code does not return.
If the fault remains after sensor and wiring replacement, consult wiring diagrams and consider testing or replacing the ABS module as a last step.

Likely causes

Wiring or connector corrosion/damage (most common)
Failed wheel speed sensor
Damaged tone/reluctor ring or debris interfering with sensor
Module fault (less common) — usually after wiring and sensor checks

Fault status

⚠️ Status

Front wheel speed sensor input circuit fault — inspect front wheel sensor, harness and ABS module.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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