P1720

Code

LAND ROVER P — Powertrain

Information about output speed loss and wheel speed

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 14 EN: 28 RU: 15

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Faulty output speed sensor (transmission output or driveshaft speed sensor)
Damaged or corroded connector or wiring (open, short to ground or battery, high resistance)
Damaged or missing reluctor/tone ring or wheel speed target
Faulty wheel speed sensor (ABS sensors) or intermittent wheel speed inputs
Poor power/ground to the sensor or control module
Faulty ABS, TCU (transmission control unit) or PCM software/hardware

Symptoms

Check Engine, ABS and/or traction control warning lights illuminated
Speedometer or odometer inaccurate or not working
Cruise control disabled or inoperative
Transmission shift issues: harsh shifts, wrong gear, or limp-in mode
Traction control/ESP unavailable or erratic activation
Diagnostic trouble codes relating to speed sensors or ABS may also be present

What to check

Read all stored and pending codes and freeze-frame data with a capable scanner
Confirm if code is historical or current and whether it is intermittent
Check live data: compare transmission output speed, input speed and individual wheel speeds at various vehicle speeds
Visually inspect output sensor, wheel speed sensors, reluctor/tone rings and harnesses for damage or contamination
Inspect connectors for corrosion, bent pins or water ingress; unplug/replug to inspect contacts
Measure sensor supply voltage and ground at the connector with key on/engine off where applicable

Signal parameters

Hall/logic type sensors: 0–5 V square wave output; typically ~0–5 V switching referenced to sensor ground
Variable reluctor (VR) sensors: AC voltage that increases with speed; low-speed amplitude often 0.1–1.5 VAC, rising with RPM
Expected frequency/pulse rate proportional to vehicle speed (consult vehicle-specific manual for pulses per mile/km)
Sensor supply (if powered type): typically regulated 5 V reference and ground from control module
Note: exact voltages, resistances and pulse rates vary by model/year — confirm with Land Rover service data

Diagnostic algorithm

Connect a manufacturer-capable scan tool, record codes, freeze-frame and live speed sensor data. Note any related codes.
Visually inspect output speed sensor, wheel speed sensors, tone rings and wiring for damage, contamination or missing teeth.
With ignition on, backprobe the sensor connector: check power (if applicable), ground and signal using DVOM or oscilloscope. Compare to expected parameters.
If VR sensor, use an oscilloscope to observe AC waveform while rotating output shaft/wheel. If Hall sensor, observe square wave and 0–5 V levels.
Check continuity and resistance of the sensor circuit back to the ABS/TCU/PCM. Repair any opens, shorts or high-resistance connections.
Perform a wiggle test on wiring and connector while monitoring live data to find intermittent faults.
If wiring and connectors are good, swap with a known-good sensor (if available) or install a new sensor and retest.
Inspect and repair/replace damaged reluctor/tone ring or wheel hub as required (replace bearing or hub assembly if ring is integral and damaged).
Verify module grounds and power feeds; repair any poor grounds or low supply voltages.
Clear codes and test drive to confirm proper speed signals and absence of code. If code returns, capture data and consider module bench testing or reprogramming per Land Rover guidance.

Likely causes

Output speed sensor failure or internal short/open in sensor
Connector corrosion or pin damage at the sensor harness
Broken or damaged reluctor/tone ring at the output or wheel hub
Intermittent wiring caused by harness chafing or connector movement
Module ground or supply fault (ABS/TCU/PCM)
Faulty ABS/TCU interpreting wheel speed signals

Fault status

⚠️ Status

Output/wheel speed signal lost, invalid or out-of-range. The vehicle control modules are not receiving a usable speed input from the output/wheel speed sensors or associated circuit.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 3.0 hours