Speak to anyone in the diagnostics industry and you'll get much the same view. Yes, the tools are there as an aid for skilled technicians but, no, they're going to struggle to understand faults, root causes and appropriate repairs without diagnostics. Why? Simply because modern trucks, trailers, buses, coaches and vans are technically sophisticated and heavily dependent on networked computer systems that defy mechanical examination.
As Mark Palin, Volvo Trucks' national technical manager, puts it: "Often today, you just can't establish truck issues using measurements and experience alone. With the scale of vehicle electronics, technicians have to rely more on their diagnostics to extract truck information, understand root causes and decide appropriate remedial action."
Delphi sales manager Paul Sinderberry agrees. "Iit's very difficult to run a fleet of trucks or buses without diagnostics. Even resetting brake pads requires recalibration. Then, for Euro 6 vehicles running SCR [selective catalytic reduction] after-treatment, there are prescribed diagnostic tests, for example, to resolve NOx errors." And Antony Alexander, of Knorr-Bremse, adds: "To work on [EBS systems] ... diagnostic software is a must. Without it, repairs can be a costly and time consuming business."
Indeed, for Volvo, its guided diagnostics – which Palin likens to fault tree analysis software, based on symptoms, rather than only fault codes – is a prerequisite for dealerships wanting to make warranty claims. "The software ensures a correct diagnosis in the right timeframe."
But, assuming you accept the latter point, whose system should you select? If you're part of a dealer network, you won't have a lot of choice: the vehicle OEM calls the shots. But, if you run a mixed fleet or you're an independent workshop, you might choose one of the all-makes aftermarket systems – such as Delphi's or Texa's. Or you might elect to go for OEM diagnostics for your mainstream work. It's all about the trade-off between pricing, up-to-date functionality and ease of use. And although received wisdom has it that the OEM approach is more expensive, it depends.
"We don't make great money out of equipment leasing and our Tech Tool software subscriptions," insists Volvo quality manager Richard Hagger. "Also, obviously we can't control what's programmed into third party tools, so if you want technical assistance, we're going to need the detailed information we get from our software." Palin adds that, while third party systems may be good, OEM diagnostics are "far more comprehensive and updated via the Internet all the time". Additionally, Volvo's software gives dealers and independents the ability to search for parts and service information on built-in catalogues.
While conceding the software updates point, Sinderberry says users can expect comprehensive functionality, certainly from Delphi. "Our software covers vans, light commercials, trucks, trailers, buses and coaches. Yes, it's an uphill battle to keep up with the OEMs, but we now have Euro 6 coverage, with online updates and the mandatory OBD [on-board diagnostics] programme. Also, one licence covers everything and technician training is FOC."
What's more, its system goes way beyond Dephi's injection systems heartland to include engine ECUs, transmission controls, braking systems, suspension, dashboard instrumentation, etc. Additionally, it looks after smaller ECUs, such as tachograph, lighting control modules, tyre pressure monitoring systems, climate control, immobilisers, etc. Delphi's DS series also handles intermittent faults, with in-flight road test data recording enabling, for example, analysis of fuel rail pressure problems.
Sinderberry says it's also easy to use. "You just select the vehicle manufacturer, the model and the year. Then choose whether you want to look at the engine, for example, or scan the whole vehicle for faults." Further, he adds that help files automatically appear for the more advanced operations.
What about the future? "Soon diagnostics will carry out remote programming. So, if an operator wants to change road speed settings or PTO settings, for example, that could be done without a trip to the workshop," suggests Palin.
But, initially no doubt, only when you use OEM diagnostics.