P18A5

Code

LAND ROVER P — Powertrain

Motion Position Sensor A - Signal Circuit

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 18 EN: 52 RU: 19

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Page language: EN

Causes

Open, short to ground or short to battery in sensor signal wire
Damaged or corroded sensor connector or pins
Faulty motion position sensor (internal failure)
Poor sensor reference voltage or ground
Water ingress or mechanical damage to sensor or harness
Faulty body/control module or poor module connector connection

Symptoms

Suspension/ride control warning lamp or message on dash
Reduced or degraded suspension functionality (stiff or fixed damping)
Incorrect or erratic position readings in live data
Stored fault code and possible limp-home behavior of suspension system
Noise or binding felt from suspension component during movement

What to check

Read freeze frame and full diagnostic data with a capable scan tool; note conditions when fault set
Visual inspection of sensor, connector and harness for damage, corrosion, chafing or water entry
Backprobe sensor connector and check for reference voltage, ground and signal presence
Wiggle test harness and connectors while monitoring live signal for intermittent behavior
Check for related codes that indicate supply, ground or module problems
Check mechanical movement of the sensor/linked component for binding or restricted travel

Signal parameters

Reference supply typically 5 V (verify factory data for exact value)
Signal typically a varying analog voltage (approx. 0.5–4.5 V) or PWM depending on sensor type
Signal should change smoothly with sensor movement and not drop to zero or rail out
No more than a few hundred millivolts of voltage drop on ground circuit under test load
No excessive noise or intermittent spikes on the signal when component is moved

Diagnostic algorithm

Connect a diagnostic scan tool, read recorded data and confirm P18A5 is current or historic; record live sensor values while cycling the suspension or moving the sensor linkage.
Visually inspect the sensor, mounting and harness for damage, corrosion, water ingress or mechanical interference. Repair obvious damage.
With ignition ON (engine off unless manufacturer instructs otherwise) backprobe the sensor connector: verify reference voltage, ground continuity and signal output. Compare to manufacturer specifications.
If reference or ground missing or out of range, trace harness to find open/short/corrosion and repair. Check continuity between sensor ground and body ground.
If supplies are correct but signal is dead, intermittent or out of range, gently move harness and connector (wiggle test) while watching live data to look for intermittent faults.
If signal appears noisy or marginal use an oscilloscope to inspect waveform while moving the sensor linkage—look for clean, continuous waveform without dropouts or spikes.
If wiring and connector check good but signal remains faulty, replace the motion position sensor with an OEM-specified part.
After repair or sensor replacement clear codes, road test and recheck live data to ensure proper operation and that the code does not return.
If problem persists and wiring and sensor are verified good, consider inspecting or replacing the control module connector or performing module diagnostics per manufacturer procedures (may require dealer tooling).

Likely causes

Wiring harness damage at suspension / chassis rub points or near wheel/turret
Corroded or loose connector at the sensor
Failed Hall-effect/position sensor element
Intermittent ground or reference supply from vehicle electrical system

Fault status

⚠️ Status

P18A5 — Motion Position Sensor A: Signal Circuit. The control module has detected an invalid or missing signal from the Motion Position Sensor A. Possible causes include wiring open/short, connector corrosion, faulty sensor, or poor reference/ground. Perform wiring and sensor checks before replacing modules.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours

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P18A5 — Motion Position Sensor A - Signal Circuit