Q. I recently changed the electric power steering pump on a Ford Focus II. The one I fitted was a TRW JER113, which I was assured was the same as the original. Since fitting it, although the power steering now works perfectly, there is a warning light continuously illuminated on the dash. According to the handbook it’s the warning light for a power steering fault. Have I done something wrong or does it mean there is another fault which I have not diagnosed correctly? Anything you can advise me on?
A. Firstly, your factor was correct in stating that our JER113 (pictured) is the same as the OE, for a very good reason. TRW manufactured the OE pump, so they are one and the same. Now to your issue with the warning light – a number of things can be causing this. Firstly, depending on the nature of the original fault, it could be that a fault code has been stored and logged in the memory.
Simply replacing the pump will not clear this. You will need to get a Ford compatible diagnostic tool, or better still a Ford OE diagnostic tool, and read and clear any fault codes stored in the memory. The most likely reason for the light being on, but the pump still working, is that you have not activated the new pump in the CAN-BUS system. With many CAN-BUS systems, when any component that is connected to the system is replaced, the new one has to be coded or programmed to the CAN-BUS controller so that it knows the component is there. Some systems will do this automatically but many need to be programmed.
The Ford is a case in point. In order to do this you will either need a Ford diagnostic tool or a compatible one that covers this function. Once you have performed this operation, I advise that you then read and clear any fault codes which may have been stored. The other area that could affect this is if your car has a steering angle sensor. You didn’t mention whether the car has one or not, but if it has ESC (Electronic Stability Control), then the chances are it has one. Assuming it has, you may need to re-calibrate the angle sensor.
When any work is undertaken on the steering and/or suspension geometry, the angle sensor must be recalibrated, otherwise the ESC may fail to work correctly and then you will also get a warning light on the dash, relating either to steering or ESC. Calibration usually involves the use of a diagnostic tool and some manual operations (such as turning the steering wheel and driving the car).
Most diagnostic tools will spell out the specific instructions which must be followed. TRW’s easycheck tool (above) features a ‘Steering Angle Sensor’ programme, covering many popular cars. If all the above fails, then you most likely have a wiring fault somewhere in the system and you will have to resort to good old fashioned fault finding and tracing.