P18A6

Code

LAND ROVER P — Powertrain

Motion Position Sensor B - Signal Circuit

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 16 EN: 23 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open, short or intermittent wiring in the sensor B signal circuit
Corroded, loose or damaged sensor connector
Failed Motion Position Sensor B (internal fault)
Contaminated or seized sensor linkage or mounting
Poor ground or missing reference supply from control module
Control module (ECM/BCM/ASC) fault (less common)

Symptoms

Malfunction Indicator Lamp (MIL) or suspension warning lamp illuminated
Suspension/ride-height warnings or reduced suspension function
Uneven ride height or vehicle sagging on one corner
Adaptive damping or stability functions limited or disabled
Diagnostic trouble code present and may reappear after clearing

What to check

Retrieve DTC(s) and freeze-frame data with a capable scan tool; record live sensor values
Visually inspect sensor B, mounting, and harness for damage, contamination, or water ingress
Inspect and reseat connector; check for corrosion, bent pins or moisture
Backprobe connector and verify sensor reference voltage (typically ~5 V) and ground
Measure signal voltage while moving the suspension/lever by hand and observe live data for smooth change
Perform wiggle test on harness while monitoring signal for intermittent behavior

Signal parameters

Reference supply: approximately 5 V (verify with vehicle-specific data)
Ground: near 0 V (good chassis/module ground)
Signal output: typically a variable voltage representing position — commonly ~0.5 V at one extreme to ~4.5 V at the other (confirm with manufacturer data)
Expected behavior: smooth, continuous change in signal voltage as suspension/lever moves; no sudden jumps to 0 V or battery voltage
Resistance (if sensor is potentiometer type): varies with travel — compare to manufacturer specification if available

Diagnostic algorithm

Connect a diagnostic scanner and read stored/active codes and live data. Note freeze frame information.
Visually inspect the Motion Position Sensor B, linkage and harness. Look for contamination, impact damage, or water ingress.
Disconnect the sensor connector, inspect pins for corrosion or damage. Reconnect and ensure secure fit.
With ignition on (engine off unless specified), backprobe the connector: verify reference voltage (~5 V) and ground integrity.
Monitor the signal pin with a multimeter or scope while an assistant moves the suspension or sensor linkage through its range; expect a smooth variable voltage. If signal is fixed, jumping to rails, or absent, suspect wiring or sensor.
Perform continuity and resistance checks between the sensor connector and the control module to identify opens/shorts to power, ground or signal.
If wiring and supply/ground check good, replace Motion Position Sensor B and retest.
If replacement does not cure the issue, inspect/repair wiring further and consider module input circuits — check for related power/ground DTCs before replacing the control module.
After repair, clear codes and perform a road test or suspension cycle to confirm proper operation and that the code does not return.

Likely causes

Damaged connector or corroded pins at Motion Position Sensor B
Broken or chafed signal wire between sensor B and control module
Failed sensor B (electrical or mechanical)
Intermittent open/short caused by harness rubbing/chafing
Missing 5 V reference or ground at the sensor

Fault status

⚠️ Status

Control module detected an implausible or missing signal from Motion Position Sensor B signal circuit; diagnostic trouble code P18A6 stored.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 2.5 hours

Similar codes

Repair manuals

Manual library for LAND ROVER

320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

Your experience will help others

+100 karma for a short comment :)

Was this AI description helpful?

Your feedback helps improve AI descriptions.

👍 Like 0 👎 Dislike 0

Send to email

P18A6 — Motion Position Sensor B - Signal Circuit