Code
C1409
Generic
C — Chassis
Brake Pressure Sensor Circuit — Range/Performance
Views:
UK: 5
EN: 3
RU: 2
AI status
Completed
Completed
100%
Causes
- Faulty brake pressure sensor (internal failure or contamination)
- Open, short, or corroded wiring or connector at the sensor
- Loose, damaged or corroded ground or reference supply
- Damaged ABS/hydraulic control unit (HCU) input circuit
- Hydraulic leak or internal brake system issue affecting sensor reading
- Low brake fluid level or air in brake lines
Symptoms
- ABS and/or traction control (ESC) warning lamp illuminated
- Brake warning lamp in combination with ABS lamp on some vehicles
- ABS or traction control may be disabled (reduced stability control functions)
- Unexpected ABS activation or reduced ABS performance
- Change in brake pedal feel or unusual behavior under braking (rare)
- Stored ABS/ESC system diagnostic trouble codes
What to check
- Scan ABS/ESC module for C1409 and any related codes; record freeze-frame and live data
- Visually inspect sensor connector and wiring for corrosion, damage, pin push-out, or chafing
- Check brake fluid level and top up if low; inspect for external leaks
- Wiggle test wiring while monitoring live sensor signal to detect intermittent electrical faults
- Check for proper reference voltage (usually ~5 V) and ground at the sensor connector
- Measure sensor output voltage while applying brake pressure and compare to expected range
Signal parameters
- Typical sensor output: analog voltage proportional to pressure (commonly 0–5 V or ~0.5–4.5 V) — refer to vehicle service data for exact values
- Reference supply: usually 5 V regulated from ABS/ECU module
- Ground: solid chassis/return ground — low resistance expected
- Signal behavior: voltage should rise smoothly with increasing brake pressure; no sudden drops, jumps, or open-circuit
- Impedance/resistance: manufacturer-specific; measure per service manual when sensor disconnected
Diagnostic algorithm
- Retrieve and record ABS module codes and live data; note when the fault sets and any freeze-frame conditions.
- Visually inspect the pressure sensor connector, wiring harness, and HCU for contamination, corrosion, or physical damage.
- With ignition on (engine off), backprobe the sensor connector and verify reference voltage and ground are present and stable.
- Monitor the sensor output voltage while slowly applying and releasing the brake pedal. Signal should change smoothly and be within manufacturer limits.
- Perform a wiggle test on wiring/connectors while watching live data to reveal intermittent opens/shorts.
- If wiring and power/ground are good but signal is out of range or erratic, replace the brake pressure sensor (or HCU assembly if sensor is integral).
- If replacing sensor does not clear the fault, suspect internal ABS module input failure; verify with manufacturer service procedures and consider module bench testing or replacement.
- After repairs, clear codes, perform required calibrations/bleeds, and road test to confirm the code does not return and ABS/ESC functions are normal.
Likely causes
- Corroded/loose connector or damaged wiring between sensor and ABS module
- Failed pressure sensor element inside the HCU
- Intermittent ground or 5 V reference supply
- Contamination or mechanical damage to the hydraulic sensor port
- Faulty ABS module input stage (less common)
Fault status
Status
Brake Pressure Sensor Circuit — Range/Performance. ABS/ESC control module has detected an out-of-range or implausible brake pressure sensor signal. ABS/traction control functions may be limited and warning lamps may be illuminated.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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Code
C1409
LAND ROVER
C — Chassis
Steering Angle Sensor — Implausible Signal
Views:
UK: 15
EN: 13
RU: 13
AI status
Completed
Completed
100%
Causes
- Faulty brake pressure sensor (internal failure or contamination)
- Open, short, or corroded wiring or connector at the sensor
- Loose, damaged or corroded ground or reference supply
- Damaged ABS/hydraulic control unit (HCU) input circuit
- Hydraulic leak or internal brake system issue affecting sensor reading
- Low brake fluid level or air in brake lines
Symptoms
- ABS and/or traction control (ESC) warning lamp illuminated
- Brake warning lamp in combination with ABS lamp on some vehicles
- ABS or traction control may be disabled (reduced stability control functions)
- Unexpected ABS activation or reduced ABS performance
- Change in brake pedal feel or unusual behavior under braking (rare)
- Stored ABS/ESC system diagnostic trouble codes
What to check
- Scan ABS/ESC module for C1409 and any related codes; record freeze-frame and live data
- Visually inspect sensor connector and wiring for corrosion, damage, pin push-out, or chafing
- Check brake fluid level and top up if low; inspect for external leaks
- Wiggle test wiring while monitoring live sensor signal to detect intermittent electrical faults
- Check for proper reference voltage (usually ~5 V) and ground at the sensor connector
- Measure sensor output voltage while applying brake pressure and compare to expected range
Signal parameters
- Typical sensor output: analog voltage proportional to pressure (commonly 0–5 V or ~0.5–4.5 V) — refer to vehicle service data for exact values
- Reference supply: usually 5 V regulated from ABS/ECU module
- Ground: solid chassis/return ground — low resistance expected
- Signal behavior: voltage should rise smoothly with increasing brake pressure; no sudden drops, jumps, or open-circuit
- Impedance/resistance: manufacturer-specific; measure per service manual when sensor disconnected
Diagnostic algorithm
- Retrieve and record ABS module codes and live data; note when the fault sets and any freeze-frame conditions.
- Visually inspect the pressure sensor connector, wiring harness, and HCU for contamination, corrosion, or physical damage.
- With ignition on (engine off), backprobe the sensor connector and verify reference voltage and ground are present and stable.
- Monitor the sensor output voltage while slowly applying and releasing the brake pedal. Signal should change smoothly and be within manufacturer limits.
- Perform a wiggle test on wiring/connectors while watching live data to reveal intermittent opens/shorts.
- If wiring and power/ground are good but signal is out of range or erratic, replace the brake pressure sensor (or HCU assembly if sensor is integral).
- If replacing sensor does not clear the fault, suspect internal ABS module input failure; verify with manufacturer service procedures and consider module bench testing or replacement.
- After repairs, clear codes, perform required calibrations/bleeds, and road test to confirm the code does not return and ABS/ESC functions are normal.
Likely causes
- Corroded/loose connector or damaged wiring between sensor and ABS module
- Failed pressure sensor element inside the HCU
- Intermittent ground or 5 V reference supply
- Contamination or mechanical damage to the hydraulic sensor port
- Faulty ABS module input stage (less common)
Fault status
Status
Brake Pressure Sensor Circuit — Range/Performance. ABS/ESC control module has detected an out-of-range or implausible brake pressure sensor signal. ABS/traction control functions may be limited and warning lamps may be illuminated.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 UAH
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
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