Code
C1250
LAND ROVER
C — Chassis
Rear inlet valve Right rear inlet valve comparison of wheel speed
Views:
UK: 5
EN: 17
RU: 10
AI status
Completed
Completed
100%
Causes
- Faulty or intermittent right rear wheel speed sensor (missing/poor signal)
- Damaged tone ring/reluctor on right rear wheel/hub
- Open, shorted, corroded or disconnected wiring/connector to the RR sensor or ABS valve
- Sticking/faulty right rear inlet valve (hydraulic modulator solenoid)
- Faulty ABS/ESC control module or internal software/firmware error
- Wheel bearing failure or mechanical issue causing erroneous speed pulses
Symptoms
- ABS and/or ESC/traction control warning lamp illuminated
- Reduced braking stability or unexpected ABS activation
- Traction control/ABS intervention when not required
- Possible brake drag or uneven braking if hydraulic valve is sticking
- Stored C1250 fault and possibly related ABS/wheel speed codes
What to check
- Scan for active/pending DTCs and record freeze-frame data and module status
- Visually inspect right rear wheel speed sensor, tone ring and axle hub for damage or contamination
- Inspect sensor connector and harness for corrosion, breaks, water ingress or pin damage
- Check ABS module power and ground circuits (fuses, relays, chassis ground)
- Use diagnostic scan tool to view live wheel speed data and compare RR wheel to other wheels at the same speed
- Spin the right rear wheel and measure sensor AC voltage or signal waveform and resistance
Signal parameters
- Wheel speed sensor resistance (Ohms) — compare to manufacturer spec
- AC voltage amplitude or pulse amplitude while spinning wheel (mV/V or Vpp)
- Signal frequency (Hz) relative to wheel rotational speed (should be linear with RPM)
- 5V reference or sensor supply voltage present at connector (if active sensor)
- CAN or wheel speed message values on ABS module during vehicle drive (bytes/Hz comparison)
- Response/feedback when commanding inlet valve (open/close) from diagnostic tool
Diagnostic algorithm
- Read and record all ABS/ESC and wheel speed-related DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Clear codes and perform a road test while monitoring live wheel speed data. Confirm C1250 reappears and under what conditions.
- Visually inspect RR sensor, tone ring and harness. Repair any damaged wiring or connectors before further testing.
- With wheel raised, spin the RR wheel and measure the sensor output (AC voltage or waveform). Compare to a known-good wheel or spec.
- If sensor signal is missing or erratic, replace the RR wheel speed sensor and retest. If signal is good, move on.
- Check power and ground to the ABS module and RR valve solenoid circuit for continuity and correct voltages. Repair as needed.
- Use the scan tool to perform an actuator test on the rear right inlet valve. Observe electrical current, valve click and the effect on wheel speed/pressure if available.
- If valve does not respond electrically but wiring and supply are correct, consider hydraulic unit fault — inspect for internal blockage or sticking solenoid.
- If ABS module shows internal errors or actuator circuits fail bench tests, follow manufacturer procedures for module repair or replacement.
- After any repair, clear codes and perform a thorough road test to confirm the fault does not return. Re-scan and verify system operation.
Likely causes
- Right rear wheel speed sensor circuit fault (sensor failure, wiring or connector corrosion)
- Physical damage to tone ring (cracks, missing teeth, heavy rust) producing erratic pulses
- Faulty right rear inlet valve solenoid in the ABS hydraulic unit
- Intermittent connector or grounding problem at the ABS module
- ABS module internal fault (less common than sensor/wiring)
Fault status
Status
ABS/ESC fault — Right rear inlet valve / wheel speed comparison out of expected range. Controller detected inconsistent wheel speed signal or incorrect valve response for right rear wheel.
Repair difficulty: Medium
Diagnostic time: 1.0 - 3.0 hours
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