Hi I’ve got focus 1.8tdci 2008 , Engine malfunction on , engine don’t start , I’ve checked earth connection , replace fuse box under the glove box still the same.really don’t know maybe ECU is the issue?

Error code on dash D900, E510

3 hours ago, Slawek said:

Error code on dash D900, E510

D900 means DTC U1900, which is a general communication error, very common and not very informative on its own.

The dash display Code E510 means DTC U2510,

U2510 - Invalid security data received from powertrain ECU (PCM).

This means there is a serious communication failure between the ECU and the IC (Instrument Cluster), and will prevent the car from starting.

CAN bus problems now seem to be very common on the 2008 Focus, and are often bad connections in connectors C112 or C113. These are under the trim by the passenger door.

Not a great picture, but C112 is near the bottom, at an angle, and C113 is the nearest to the front, under the screen, and is a bit hard to get at. But C113 has been the culprit in a couple of cases at least.

It is not likely to be the ECU itself that is the problem here. The IC is frequently suspected, but for years other than 2006 (like mine!), I think it is less likely to be the IC, and more likely to be connectors.

A rather long & winding thread with a happy ending, at least with the fault located if not cured, is: