POWER-ASSISTED STEERING
Fault finding – System operation
36B
36B-7V5 MR-372-J84-36B000$132_fra.mif
EPAS
Vdiag no.: 05, 09,
0DPOWER-ASSISTED STEERING
Fault finding – System operation
GENERAL OPERATION
On this vehicle, the steering system is power-assisted by an electric motor attached to the steering column.
The action of the driver is relayed by a torque sensor, which measures the force applied to the steering wheel,
and a steering column angle sensor (steering wheel angle sensor only on Vdiag 05 and 09). Assistance is given
by an electric motor which applies more or less torque to the steering column, in one direction or the other.
A computer controls this assistance according to several vehicle environment parameters, including the vehicle
speed.
EPAS ALSO OFFERS THE FOLLOWING:
Active recall:
This function is used to bring the steering wheel back to the straight-ahead position when driving at low speeds but
not when the vehicle is stationary. This function is normal on hydraulic power-assisted steering vehicles or vehicles
without assistance.
This function cannot be deactivated by the diagnostic tool.
For Vdiag 05 and 09 (columns with steering wheel angle sensor): this feature is inactive when the steering wheel
angle is not available (ET020 Programming steering wheel angle sensor for STATUS 1, STATUS 2, STATUS 3).
For Vdiag 0D (columns without steering wheel angle sensor): this feature is always inactive.
Lock torque limit:
This function limits the assistance torque when the steering wheel is held at full lock with considerable effort, when
the vehicle is stationary or travelling at a speed less than 3 mph (5 km/h). The purpose of this function is to limit
overheating of the electric power assisted steering motor.
Note:
When the computer detects a fault, the level of assistance can be modified depending on how serious the fault is.
An incorrect or absent vehicle speed signal results in assistance equal to that provided at 60 mph (100 km/h)
without active recall. The EPAS sends a steering wheel angle signal to the ESP computer (if fitted).
MR-372-J84-36B000$132_fra.mif
