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The Proviso™ 88P

The Proviso™ 88P is an electronic lift axle control system for trailers, designed to automatically lift and lower the axle at the correct times to avoid safety and overweight issues. The 88P senses the weight, direction, and speed of the trailer and controls the lift axle’s position. The 88P is intended for self-steering lift axles.

The 88P also provides controls for an in-cab switch and light, an axle position sensor, a speed based steering lock, and a max load indicator. The 88P can be used to broadcast the the lift axle information, using a 3rd party device.


  • Automatically lifts and lowers based on weight
  • In-Cab control switch and position light
  • Reverse lift
  • Max load indicator
  • Speed based steering lock
  • Approved for use in the Western Provinces

How it works

Load Control

The load control feature uses pressure measurements made by the built in pressure transducer. When connected to the fixed axle’s suspension, the pressure measurements can be used as a rough estimate of weight. The 88P allows the installer to select the pressures at which the axle should lift and lower. Selection of these pressures is important to ensure the lift axle lowers in time to avoid overweight issues and lifts in time to avoid unwanted wear to the lift axle.

Reverse Lift

The reverse lift feature uses the Wheel Monitor Reverse Sensor to determine the trailers direction. When the trailer has reversed approximately 8 inches, the reverse lift feature activates. The Reverse lift feature remains active until the trailer moves forward 100 feet without stopping.

In-Cab Switch

The In-cab switch allows the operator to lift the axle at any time. When the switch is off, the 88P will control the axle position. The switch is only permitted in specific applications, such as logging trailers.

Max Load Indicator

The max load indicator uses the same pressure measurements as the load control. Once the pressure reading is close to the max load pressure, the indicator will flash. It will become solid on, once the pressure exceeds the max pressure setting. The setting is also set by the installer and important for accurate operation.

Steering Lock

The steering lock control is used to power a solenoid that inserts a locking pin. The 88P activates the lock in reverse and above 60km/h. The lock is deactivated with traveling forward below 60km/h.


General Information

Installation Manuals

88P Kits

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