Using the Davie XD
Page 38
If you've noticed an error in this article please click here to report it so we can fix it.
The XD offers a comprehensive choice of measurements with two multimeters for checking voltages, resistances or currents at any one time. The two oscilloscopes are mounted one above the other to display the actual signal and an example with which to compare it. The XD can test diodes and works in AC or DC.
Less experienced users can switch the XD to 'automatic' it will then recognise a signal's voltage and frequency, set its own scales and self-calibrate. There's signal cycle mode and a freeze-frame for examining signals in detail.
In 'direct' test the mechanic inputs the vehicle chassis number and waits for the XD to locate the truck among its build records. Pre-production units like our CF tractor will not show up, but the chassis detail can usually be located by interrogating Des Rapid° parts system.
Alternatively, the mechanic can switch to 'manual', select DIP (digital instrument panel) and wait for an ID on the chassis. You can then check the ECU for errors or functions.
In 'guided' diagnoses the mechanic initially brings up a reference curve and signal measurement. This either identifies a fault or tells you that all's well and it's time to take the next step.
To find a typical fault of say, a fuel gauge reading low, attach the XD and select 'direct' mode. Go to 'gauges', log into the panel and choose the particular gauge. If it's OK then either pick your next check or go to 'guided' mode and let the XD advise you. You can check gauges or lights remotely and independently by detaching the XD's basic panel with its LCD touch screen and taking it into the cab. Using the right interface and multiplexer links, it simply takes command. The unit can test the ECAS system, raising and lowering the chassis from the Davie screen; it systematically checks resistances, cables and all valve functions. It can check the sensor values as the suspension cycles, the ride height and the EP valve. It will also highlight any incorrect item in the system, particularly the ECU.
The Davie XD certainly seems to be robust. It will charge its spare batteries two at a time—one battery should last for 45 minutes when working remotely.