Diagnostic tools are increasingly being used to identify and rectify
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faults found in trucks. CM analyses how these tools can help technicians in their day-to-day wor‘and how much you should be paying for equipment.
Words: Sharon Ciancy The proliferation of electronic control systems on trucks and trailers has certainly complicated servicing. A truck may have a number of Electronic Control Units (ECUs) activating various mechanical systems, such as clutch control, brakes and fuel injection systems to name but three.
As a result, workshops have had to 'up' their skills, and their mechanical expertise. Technicians now need to be able to diagnose if a fault is electronic or mechanical.
Some checks can only he done with a diagnostic tool — a fault-code reader and sensor operation, for example.
Even if the fault is mechanical, once it is fixed. access to the ECU is often essential in order to clear a fault code or reconfigure it so it recognises a new part has been fitted.
Diagnostic tools can be a great time-saver by allowing technicians to pinpoint electronic and electrical faults more quickly. Truck-specific multi-make and multi-system diagnostic software is now widely available, but the adage about getting what you pay for certainly applies here.
Multi-make, multi-system diagnostic tools are not cheap. They typically cost upwards of £1,500, while sensor-function tools tend to cost under £300.
"A lot depends on what type of servicing activity the workshop is doing." says Jeff Lowe of Dr Air Brake, the trailer diagnostics specialist. '-If you just need to confirm that trailer systems are performing correctly, you don't need an all-singing all-dancing diagnostics tool."
Air brake and clutch specialist Drakelield reckons that 80% of all EBS/ABS brake problems are sensor-related, so rather than interrogating the ECU, the company's SensorMaster connects to the sensor socket on each wheel. You are going straight to the heart of most problems," says Barry Craven, diagnostic engineer. 'It does a complete test cycle of six of the most common causes of EBS/ABS faults in 15 seconds."
The type of device the diagnostic software is running on also determines price. A laptop or tablet PC rugged enough to cope with life in the workshop will set you back about £1,500, and that's without factoring in the cost of software licences. Not all diagnostics tools, however, require a large screen. Some tasks can be done with a smaller handheld computer.
Remember to include the cost of regular software updates. With most software licences, you pay an annual subscription that grants you access to updates throughout the year that can be obtained and installed over the internet.Technical assistance is often included in the fee.
Ease-of-use The latest generation of diagnostics kits use a separate data capture unit that plugs into the FMS diagnostic port in the cab and communicates with the vehicle's ECUs The data is sent via Bluetooth to a handheld terminal. As a result, the technician can move around the vehicle without having to worry about trailing cables.
Multi-make, multi-system diagnostics kits have menu-driven software that will take a technician through a step-by-step process that includes selecting vehicle make, model and the system to be diagnosed.
Manufacturers regularly release software updates, adding more vehicle makes, models and systems. Remember to check that the makes and models in your fleet are covered.
Fixing the fault It's also worth remembering that there are differences to the amount of help diagnostic tools can provide a vehicle technician. Some are designed simply to pinpoint a problem. Others offer ECU recalibration tools, wiring diagrams as well as tips on fault rectification.
"The ECU has to re-learn, for example, the maximum and minimum travel positions of the clutch via the clutch travel sensors." points out diagnostic instrument-maker 'Iexa. "Without a diagnostic tool to do this, you face a trip to a franchised dealer or repair specialist, with added costs and downtime." Trailer diagnostic kits
Trailer diagnostics is relatively simple compared with trucks. Most faults are related to braking systems (including electrics, air supply and ABS operation) and light functions CANbus wiring has made tracing electrical faults simpler. while an ECU unit for the brakes incorporates a diagnostic facility.
'With fewer checks to carry out, it's tempting not to invest in trailer diagnostics," says John Hope of trailer diagnosis equipment specialist Hope Technical Developments (HTD)."Often, though, all that is needed is confirmation that the basic systems are operating correctly or that a fault is present.
"Only those trailers needing further diagnostic checks, fault rectification or a pre-annual test service need to come into the workshop."
HTD is one of several companies addressing this need for in-situ' trailer checks through the use of its portable Compact Scrutineer tool. Hope explains: "It will usually last a full day on one charge. No diagnostic skills are required because the function check is automatic, so your top technician doesn't have to be doing basic checks" A Wabco's Trailer Check Fault location Reported trailer faults can actually be a truck problem, says Drakefield's Barry Craven. -You need to confirm that the fault is actually on the trailer, and not an electrical problem on the tractor unit."
Drakelield ISO Check
cable does just that by conlirming the ISO connectors between tractor and trailer are actually working.
The cable has a conventional ISO connector at one and a specially designed connection at the other that incorporates some clever electronics and a ring of red and green LED lights.
The electronics automatically test the pin connections and correct voltage levels in the ISO socket, including pin 5, which triggers the ABS warning light in the cab if it does not have a five-volt supply.
Don't forget the power
All trailer diagnostic tools require an independent power source. An unavoidable issue with trailer diagnostics, though, is that all the air and power connections are at the front of the trailer, and all the working components are found at the rear. This can present a problem for sonic checks (on automatic slack adjusters, for example) where the technician needs to observe the functioning of the component.
As a result. this often ties up two workshop people, hut remote control set-ups on systems like the Scrutineer, Dr Airbrakes Trailer Check arid Drakefield's Trailermaster solve this.
Dr Air Brake's remote control can also double-up as an ABS fault diag,nostic tool, Code-Talk. It can communicate with Wabco. Haldex and Knorr-Bremse ABS control systems and display a fault description, not just a code that the technician must then look up. The Trailer Check will clear historic fault codes.
This is ideal for a workshop, because you can check that the rectification is effective and that the fault code is not reported again. • A Hope's Compact Scrutineer features remote-control operation