Topic

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.

I've revisited this 'How to' as, although the steering wasn't self steering left anymore, it still turned left more easily than right. So I decided to try adjusting the EPAS sensor by the slightly more technical method as described on the www.mgf.ultimatemg.com website.

The method is the same as the previous method, up to and including point 11.

Before loosening the two bolts on the sensor(point 12), Follow the cable from the sensor, it is connected into the wiring loom at a plug attached to the steering column behind the sensor position. You can pull the connector off the column and then disconnect it.

If you look at the plug from the sensor, you will see 4 pins connected to the 4 coloured wires. (Red) 5+v; (Black) -v; (Yellow) sensor output; and (Green) sensor output.

Basically you need to run a 4 to 6 volt battery through the red and black wires. Then you connect a voltmeter across the green and yellow pins. Initially on 0-2 volts scale. Then on 0-200 millivolt scale.

What you are looking for is a 0 volts reading across the sensor pins.
With the steering in the straight ahead position, I got an initial reading of 0.070volts, and as I say the steering was OK, but was definitely easier to turn left.
Keith Starbuck (author of the article on the website) recommends less than 10 millivolts.(0.010volts)

I then loosened the sensor bolts and moved the sensor until I got as near 0.000volts as I could.
I managed to get it down to 0.002volts.
So I re-tightened the bolts and checked again. Still 0.002 volts.
I then refilled the slots with silicone sealant.
I reconnected the plug and cable-tied it to the steering column in the same position.

I then followed the rest of the above 'How-to', from point 19.

On the test drive the steering felt much better balanced, with no bias either way. Result!
Total time - about 1 hour. Not a difficult job.

Edit - I found that the job was easier when I undid the two bolts that hold the frame (that the fusebox attaches to) and moved that aside, as well as the fusebox.

Having done three of these on the service day, there are two additional points to mention:-

1/. There is an older type sensor with 6 wires instead of 4. I could not adjust this sensor using a multimeter.
I adjusted it with the first method.

2/. The job is easier if you remove the main plastic fascia cover. It is held in by 2 screws. Loosen these 2 screws and pull the cover off.
Replace after the adjustment is complete.

HI I have this problem with my mgf, it wants to steer to the left at slow speed, should i turn the sensor clockwise or anticlockwise. please can you help me thank you. Chris.

chrisd300 wrote: wrote:

HI I have this problem with my mgf, it wants to steer to the left at slow speed, should i turn the sensor clockwise or anticlockwise. please can you help me thank you. Chris.

You really need to use a multimeter to get it right. The adjustments are so small that you could spend a lot of time fiddling back and forth.
I can't recall offhand which way you adjust it, as it's been a while since I did one.

Thanks for this guide, was a great help in fixing the self-steering!

Glad it helped!

Did this the other day, using the multi meter method. Pretty straightforward after reading David's guide ( along with advice pointing to the multimeter instructions, so thanks to those chaps too). We no longer turn left at every opportunity.

The cover over my sensor assembly was held on with two bolts, which also had pozi slots in the top. They were pretty soft, and on quite tight, so my advice is to be careful you get your screw driver at the correct angle because it was easy to trash the slots. Well, it was on mine, whilst hanging upside down under the dash!

When connecting the meter, I found the spade terminals a bit big, so I cut them in half and tightened them slightly with pliers.

Excellent instructions, thank you; I don't know how you have the patience to photograph every step! Mind you, I'm glad you do.

This information really helped me today. Used the multimeter method and was done in an hour. Trial and error would seem to me to be a very time consuming method. Thanks again.