Andy Mudie, DAFaid and aftersales system manager at DAF Trucks, recounts that 20 or more years ago most calls to the manufacturer’s breakdown assistance service related to actual physical component failures and it was often apparent what these were before the van had even stopped by the casualty vehicle. “You might well see a pool of coolant, or a trail of oil on the road surface,” he remembers.
Sudden catastrophic failures are increasingly rare, but drivers are more inclined than ever to summon help when dashboard warning lights are illuminated. And, the changing nature of the transport business, with more trucks being operated by large logistics concerns, can complicate the situation further.
“In many cases, the big fleet driver will not call the DAFaid helpline direct, but will call the operator’s own call centre, which then calls DAFaid. The problem is, at this point, that the information we get will be second or third hand, and deeper questioning about the fault is not always possible.”
And this is important. “There is a big difference in what the appropriate action to take might be. If a yellow warning lamp is illuminated, then it is perfectly OK to drive the truck under its own power to a suitable workshop for attention. A red light, however, means stop as soon as it is safe to do so,” Mudie says.
That can mean the difference between alerting the nearest workshop to expect the truck or sending out a DAFaid van to attend at the roadside, and even preparing to tow the casualty truck in.
Direct contact with the driver can also speed the diagnostic process, even though the number of drivers who are competent mechanically is falling by the day.
“A lot of these faults are sequential,” Mudie explains. “One component or sensor will fail initially, but then other systems will report faults as they cease getting inputs from the original failed component.
“For instance, a failed speed sensor will generate warning lights in the braking, cruise-control and all other systems that need information on the vehicle’s road speed, so you get a cascade of warning lamps.
“Being told that the dash is in Christmas tree mode isn’t as helpful to the technician as it is to be told which light came on first, and how long ago that was,” he recounts.
GENERATIONAL CHANGES
The technician also needs to know where the truck is. Traditionally, drivers had good knowledge of the road network and local landmarks, but these days the DAFaid call centre often has to ascertain the casualty’s location using Google Maps and What Three Words.
The nearest three DAF workshops are then contacted and the one that can deal with the problem soonest is allocated the task. On non-warranty work, the operator’s own DAF dealer will invoice the operator for the work, so it has to be established which dealer the operator holds an account with.
Mudie recounts a generation gap between technicians who trained originally on older vehicles and those who entered the industry in the electronic era: “The older guy will take a walk around the vehicle and look, while the younger technician will plug the diagnostic tool in straight away.”
He suggests the best approach is to plug the tool in, then do a walk-around while it boots up. The tool will generate error codes that show which warning lights came on and when, and what the causes might be and suggests possible fixes. “It tells the technician what the ECU saw and what caused it.”
ACTION FAULTS
At Volvo Trucks, while most of the processes are similar to DAF’s, particularly the actions required after an amber or red lamp appears, the driver of the casualty vehicle can streamline the process and summon help by pressing a Volvo Action Service button in the cab.
“Pressing it a second time transmits the recorded DTCs (diagnostic trouble codes) to Volvo Action Service for use by the callout technician,” reports Brent Norton, national technical manager at Volvo Trucks UK & Ireland.
Norton adds only the most experienced and highly trained technicians are selected for breakdown duties, and they can contact their dealer for further advice, if necessary, once on scene.
Some of the faults that generate yellow lamps will cure themselves, but this does not mean that they can be ignored, Mudie warns.
“A lot of yellow lamp error codes can clear after two ignition switch cycles,” he reports. “This is particularly true of the exhaust emissions warning light. The truck may well be sensing an obstructed PM filter but can cure itself through an in-service regen.”
But he warns that repeated warnings should not be ignored. “All these faults are recorded and will be visible to the technician the next time the system is interrogated as ‘inactive’ faults,” Mudie says.
“A persistent emissions control fault will result first of all in an engine ‘detorque’ which will be noticeable to the driver as a fall in performance as well as restoring the emissions compliance of the truck, and then eventually a speed restriction and a red warning lamp.”
ON THE ROADSIDE
Mudie warns that if things have got this serious, the chances of a roadside ‘fix’ are slim. “We do have operators who ask if we can just ‘put the light out’, clear the fault to allow them to get the vehicle home, and in some circumstances this might be acceptable.”
Operators of DAF-engine coaches are more likely to do this than truck operators are, he reports, as coach companies are far more likely to run their own workshops.
DAF technicians have training on coaches, but one key difference is how diagnostic information is accessed. “On trucks, the tech will enter the VIN or chassis number, so the diagnostic tool knows what vehicle it is looking at. On coaches, the VIN is meaningless to the system, so the engine number is entered instead.”
And a DAF technician’s expertise does not end at trucks and coaches, at least not in some areas, Mudie recounts. “Our dealer in Norfolk, Chassis-Cab, gets call-outs to go and deal with farm machines…particularly beet harvesters which often have DAF engines.
“Alongside its DAFaid vans, it runs DAFaid Land Rovers, so the technician can get out to work on harvesters in the middle of muddy fields.”
MEN OF PARTS
While DAFaid technicians will often pick up specific parts to deal with a service call, their vans also carry an inventory of spares.
Just what is carried depends on what’s in the DAF customer parc in the local area: for instance, if there’s a large fleet using the lighter Cummins-engine DAF models, then more commonly used parts for these will be carried than on a van based near a major national transport corridor where heavier long-distance trucks predominate.
Thankfully, truck fires are mercifully rare these days, and pretty much all have a common cause: smoking. “Most fires can be traced to lit cigarette butts thrown from a vehicle: not necessarily the truck itself,” Mudie asserts. “If a lit butt is drawn into the air-intake, then the flow of air through the paper filter will ignite it.
“We’ve even had lighters left on top of the dash on a sunny day that have ignited in the heat and set fire to the cab interior.”
