Code
C1440
LAND ROVER
C — Chassis
Failure in the main / primary signal of the pressure transducer
Views:
UK: 5
EN: 15
RU: 11
AI status
Completed
Completed
100%
Causes
- Damaged or corroded sensor connector or wiring (open, short to ground or battery, intermittent)
- Failed pressure transducer (internal electronics or diaphragm)
- Loss of sensor reference supply (5V) or ground
- Faulty ABS/ESC control module or internal input circuit
- CAN / network communication errors affecting sensor data
- Water ingress, contamination or mechanical damage to the sensor or harness
Symptoms
- ABS and/or ESC warning lamps illuminated
- Reduced/no ABS function; traction control may be disabled
- Brake/ABS warning message on dash
- Possible degraded braking feel or warning of system fault
- Fault may be intermittent or present continuously
- Related driveability or stability systems inhibited
What to check
- Read freeze-frame and live data with a diagnostic scanner; note conditions when fault set
- Visually inspect sensor connector and harness for corrosion, damage, and secure fit
- Check associated fuses and battery supply to the ABS module
- Backprobe sensor connector and confirm reference voltage (typically ~5 V) and good ground
- Measure sensor output signal with multimeter or scope while applying pressure (pedal or hydraulic pressure) and while cranking/engine running
- Perform wiggle test on wiring and connectors while monitoring signal for intermittent faults
Signal parameters
- Sensor supply (reference): typically ~5 V (verify OEM spec)
- Sensor output (main/primary): commonly 0.5–4.5 V proportional to pressure; at rest often near low end (~0.5–1.0 V)
- Open-circuit: infinite resistance / no output; short to battery: output near battery voltage (~12 V)
- Good ground: near 0 V; high resistance ground or intermittent ground will cause unstable/erratic output
- Signal should be smooth and change proportionally with applied brake/hydraulic pressure; no repetitive spikes or dropouts
Diagnostic algorithm
- Connect a compatible scan tool, read DTCs and freeze frame, clear codes and attempt to re-create fault to confirm persistence.
- Visually inspect sensor, connector and wiring harness for damage, corrosion, fluid ingress or poor seating; repair as needed.
- With ignition ON, backprobe the sensor connector: confirm 5 V reference (or OEM spec), ground continuity and that the signal wire is not shorted to power or ground.
- Monitor the sensor output with a DVOM and/or oscilloscope while operating the brake system (apply pedal or run hydraulic pump). Verify output changes smoothly and is within expected voltage range.
- If signal is open, shorted, stuck or erratic, isolate wiring by disconnecting harness at sensor and re-check for shorts to ground/power; repair wiring or connector.
- If wiring and supply/ground are good but the output is incorrect, replace the pressure transducer and retest.
- If a new sensor does not clear the fault and wiring is verified good, inspect/replace ABS/ESC control module or reflash/update software per manufacturer guidance.
- After repairs clear codes, perform a road test and recheck for DTC reappearance and correct operation of ABS/ESC systems.
Likely causes
- Connector corrosion or wiring chafe causing intermittent/shorted signal
- Failed pressure transducer (most common if wiring checks good)
- Lost 5 V reference or ground at the sensor
- ABS module input circuit fault or software anomaly
- Contamination (fluid/water) inside sensor or connector
Fault status
Status
C1440 — Main/primary signal fault from the brake pressure transducer. The ABS/ESC control module detects invalid, missing, or out-of-range voltage/signal from the pressure sensor.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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