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Home / DTC / C1440 — Failure in the main / primary signal of the pressure transducer

C1440 — Failure in the main / primary signal of the pressure transducer

Detailed page for trouble code C1440.

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Code

C1440

LAND ROVER C — Chassis

Failure in the main / primary signal of the pressure transducer

Brand: LAND ROVER
Type: C — Chassis
AI status
Completed
ready
Completed 100%
Page language: EN

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

  1. Connect a compatible scan tool, read DTCs and freeze frame, clear codes and attempt to re-create fault to confirm persistence.
  2. Visually inspect sensor, connector and wiring harness for damage, corrosion, fluid ingress or poor seating; repair as needed.
  3. 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.
  4. 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.
  5. 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.
  6. If wiring and supply/ground are good but the output is incorrect, replace the pressure transducer and retest.
  7. 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.
  8. 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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C1441 C1450 C1200 C1100 U0121 U1100
413

Browse 413 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

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Code

C1440

Other C — Chassis

Pressure Transducer Main / Primary signal Faulted

Brand: Other
Type: C — Chassis
AI status
Completed
ready
Completed 100%
Page language: EN

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

  1. Connect a compatible scan tool, read DTCs and freeze frame, clear codes and attempt to re-create fault to confirm persistence.
  2. Visually inspect sensor, connector and wiring harness for damage, corrosion, fluid ingress or poor seating; repair as needed.
  3. 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.
  4. 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.
  5. 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.
  6. If wiring and supply/ground are good but the output is incorrect, replace the pressure transducer and retest.
  7. 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.
  8. 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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