The EPAS fault.
Does your steering pull to the left? Does it seem to be worse at slow speeds? Is it easier to turn left than to turn right? Or rarely, the opposite might be true.
If the answer is yes to all of these questions then it could be the Epas fault.
What's that then?
Epas is simply the
Electrically
Power
Assisted
Steering.
Basically, the steering is assisted by an electric motor. There is a sensor on the steering column that detects when you turn the wheel and triggers the motor to assist.
Unfortunately, it is quite common that over time, the sensor becomes misaligned. This usually results in the sensor telling the motor to help turn left even when you want to steer straight ahead.
To test whether this is the problem:-
1 Safely jack up front of car.
2 Centralize the steering wheel.
3 With car in NEUTRAL, switch on engine. Watch steering wheel, if it turns to the left ( or right) all by itself you need to adjust the EPAS sensor.
To adjust the sensor:-
4 Turn off engine, re-centralize wheel.
5 Disconnect battery.
6 Open compartment under steering wheel.
7 Undo two bolts holding fuse box, and move it aside. Wrap the fusebox in a plastic bag to guard against shorts later.
8 Behind there, on the steering column you'll now be able to see the sensor covered by a metal shield, remove shield.
9 The sensor is held to the steering column by two bolts in adjustment slots.
10 The slots are filled with a glue/filler, to prevent the sensor from moving.
11 Dig out the filler material from the slots in the sensor.
12
Loosen the two bolts holding the sensor. (Do not remove them!)
13 Rotate the sensor a small amount. Hand tighten the two bolts.
14 Making sure that the fuse box is safe, reconnect the battery.
15 Start the car and observe the steering wheel. If it moves less or moves more slowly, you have turned the sensor in the correct direction.
16 As necessary, repeat steps 4 to 13 until the steering wheel doesn't move from the centralized position..
17 When you're happy repeat steps 4 and 5.
18 Tighten bolts properly, use silicon sealant or glue to fill the slots up again.
19 Refit the shield and then the fuse box.
20 Reconnect the battery, and check the steering wheel still doesn't move.
21 Close up the compartment under the steering wheel.
22 Let the front of the car down.
23 Test drive.
24 Have a coffee and pat yourself on the back!
For further information and photos, have a look at this site:-
http://www.mgf.ultimatemg.com/group2/common_problems/epas_reset/index.htm
The site explains a more technical method of centralizing the sensor as well as the method above.