I have a Focus 1997cc TDCi and have a problem that a garage has failed to solve.

My car shows the 'Engine systems fault' message and also the red warning light comes on.  The car then cannot be driven at more than about 10 mph or appears to go perfectly normally but won't rev above 2500 rpm.

I'm virtually sure that there is nothing seriously wrong with the engine but there is a faulty connection somewhere triggering the fault message and I also think that the faulty connection could be caused by water.  I think this because after a long spell of dry weather the car worked perfectly with no fault messages.  It then rained and the next time I used the car the fault message appeared.

If anyone has come across this sort of fault and knows how to solve it by saying, for example, where the rain could be getting in and causing a bad connection, I really would be extremely grateful as I'm getting desperate since no-one appears to know how to cure the problem.

1 hour ago, John C B said:

My car shows the 'Engine systems fault' message and also the red warning light comes on.  The car then cannot be driven at more than about 10 mph or appears to go perfectly normally but won't rev above 2500 rpm.

Unfortunately this describes most engine problems. You need to read the fault codes and come back.

As Luke says, you need the DTC codes to give a clue to the problem. Yes it could just be something as simple as the wire to the crank position sensor has corroded, but it also could be a hundred other things. Get the fault codes and it will help

Thank you very much for your replies, I really do appreciate it.  I will now try to get the fault codes.

I called out the RAC and the fault codes were P2135 and P193B which are to do with the throttle position sensors.

The RAC man then noted that it looked as though the throttle was new and indeed it had been replaced when I last took the car to be repaired.  He then checked some of the wiring harnesses and could not find any obvious faults.

I was very impressed with what the RAC man did and, considering the circumstances, don't think he could have done any more to find the fault.

As mentioned before the fault consists of Engine Systems Fault being displayed and the red warning light showing.  Recently the engine seems to run perfectly up to about 2500 rpm but will not rev higher than this.  Also, recently, the display has sometimes gone blank and the red warning light showing yet the car still appears to run perfectly up to 2500 rpm.

I fully appreciate that although the above troubles may be due to a simple fault such as a loose connection or faulty sensor, rather than a serious fault with the engine, actually pinpointing the fault could be extremely difficult, not to mention expensive.

If anyone has come across such a fault as described above and could suggest how it could be corrected then, as mentioned before, I truly would be so grateful.