Carry out a road test and drive the car at a constant speed of 30 km/h.

Check the reading on the diagnostic instrument for:

· Left front wheel speed (ASX)

· Right front wheel speed (ADX)

· Left rear wheel speed (PSX)

· Right rear wheel speed (PDX)

and ensure they approximately coincide with the speed shown on the instrument panel.

The test can be considered over

Continue the road test and check whether the Diesel EDC16C39 electronic injection control unit displays the error P055 - Vehicle speed signal.

Move on to Step 6

Continue driving at a constant speed of 30 km/h.

Check the ABS TRW EBC 430NG control unit to see whether the diagnostic instrument reading for:

· Left front wheel speed (ASX)

· Right front wheel speed (ADX)

· Left rear wheel speed (PSX)

· Right rear wheel speed (PDX)

is not within range between 15 and 45 km/h. Continue to step 5.

Replace the ABS control unit

Op. 3340A12 ABS HYDRAULIC AND ELECTRONIC CONTROL UNIT - R.R.

Move on to Step 4

Check the fault disappears.

The test can be considered over

Repair the original ABS control unit and replace the engine management control unit

Op. 1060G80 DIESEL ELECTRONIC INJECTION CONTROL UNIT - .R

Replace the engine management control unit

Op. 1060G80 DIESEL ELECTRONIC INJECTION CONTROL UNIT - .R

The test can be considered over

Go back to the workshop and turn off the engine.

Turn the ignition key ON.

With the engine off, lift the vehicle and turn the left front wheel slowly by hand.

Check that the reading for the Left Front Wheel (ASX) speed in the ABS TRW EBC 430NG control unit is greater than 1 km/h.

Replace the ABS control unit

Op. 3340A12 ABS HYDRAULIC AND ELECTRONIC CONTROL UNIT - R.R.

Move on to Step 4

Replace the instrument panel and check that the fault has disappeared

Op. 5560B10 CONTROL PANEL - R+R

Repair the original instrument panel and replace the engine management control unit

Op. 1060G80 DIESEL ELECTRONIC INJECTION CONTROL UNIT - .R