A2
| Design and function |
| The EPHS steering system (Electrically Powered Hydraulic Steering) varies the degree of power assistance according to the road speed and the rate of change in the steering angle. |
Note!| The steering hydraulics pump -V119- consists of a gear pump → Item and an electric motor → Item. |
| A gear pump integrated in the motor/pump unit is used in this steering system in place of the power steering pump (vane pump) in previous power-assisted steering systems. |
| This gear pump → Item is not driven directly from the engine, but by an electric motor → Item integrated in the motor/pump assembly. |
| The electric motor → Item only runs with the ignition switched on and when the engine is running. |
| Signals for road speed → Item, engine speed → Item and rate of change in steering angle → Item are transmitted to the control unit → Item. This control unit regulates the speed of the electric motor → Item as well as the gear pump → Item and thus the delivery rate or flow rate of the hydraulic fluid. |
| 1 - | Power steering box |
| 2 - | Power steering sensor -G250- |
| q | Only installed up to chassis number 8Z1 N019 007 and from 8Z1 N019 032 to 8Z1 N019 035. |
| q | A power steering sensor is no longer fitted as of chassis number 8Z1 N019 036. This function has been taken over by steering angle sender -G85- |
| 3 - | Steering column |
| 4 - | Control unit with display in dash panel insert -J285- |
| 5 - | Speedometer sender -G22- |
| 6 - | Engine control unit |
| 7 - | servotronic warning lamp -K92- |
| q | In dash panel insert, connected via CAN BUS |
| 8 - | Signal for servotronic warning lamp -K92- |
| q | Transmitted via CAN BUS |
| 9 - | Engine speed signal |
| q | Transmitted via CAN BUS |
| 10 - | Road speed signal |
| q | Transmitted via CAN BUS |
| 11 - | Banjo bolt with non-return valve |
| 12 - | Expansion hose |
| 13 - | Signal for rate of change of steering angle |
| 14 - | Return line |
| 15 - | Motor/pump unit, consisting of: |
| a - | Screw cap |
| b - | Hydraulic fluid reservoir |
| c - | Pressure limiting valve |
| d - | Gear pump |
| e - | Power steering control unit -J500- |
| f - | Electric motor |
| 16 - | Power steering terminal +30 |
| 17 - | Power steering terminal +15 |
| 18 - | Earth - |