SO WHAT'S YOUR PROBLEM?
Page 104
Page 105
If you've noticed an error in this article please click here to report it so we can fix it.
It seems that almost everything you touch on new trucks is, or is about to be, controlled by electronics— from ABS brakes to speed limiters and gearboxes. Soon, emission legislation will force full electronic engine control. So what do you do when they go wrong? Do you roll your sleeves up and get out the instruction manual? Or is it a case of "I know a man who can"?
While electronics have answered some engineering problems for the truck manufacturers, they have created a whole host of them for the aftermarket. These hi-tech trucks need hi-tech repairs but, if you listen to the pundits, the gap between vehicle technology and the repair skills in the workforce is widening at an alarming rate. But, just as electronics have solved braking, emission and gear selection problems, they can and will ease the burden of the repairing workshop.
Diagnosis is the magical word. It's not fixing the vehicle but finding out where the fault lies. Replacing one component after another until the fault disappears is both time-consuming and costly. But by pinpointing which component is faulty and just replacing it, both cost and downtime is kept to a minimum.
Admittedly, the old system of everything being mechanically or pneumatically operated would prevent the creation of such problems but that option is no longer open. The electronics used on trucks will continue to increase for some time. Trucks will soon have as much electronics on board as many cars — most will be dictated by legislation.
In many ways the road haulage industry has been its own worst enemy by not spending one penny more than it has to on a truck or its maintenance. But in this case it may have worked to its advantage. On the car side the green welly, Volvo, I do own the road and fluffy dice brigades have had over a decade to adjust to the increased level of electronicsBut, reliabilit-y, repair costs and
downtime are not the problem they are on the CV side.
Now that legislation is forcing the use of electronics on CVs the reliability and faultfinding procedures and systems are reasonably well developed. Many diagnostic systems are as yet still for the cars, but the computers that drive them are easily reprogrammed for use on trucks when the need arises. Many truck manufacturers have, or are working on, diagnostic computers to cope with the electronics used in their products. While Scania is finalising its system, Iveco Ford's Modus is due to hit the dealers any day now Modus is an expert system which will take a technician step-by-step through the fault-finding process on air brakes, engines and speed limiters. After entering the vehicle details on the computer manually or by using a VIN (vehicle identification number) the computer will ask what area, brakes, engine and so on, is to be investigated. Having entered that via a touch-screen system, the menu gives several descriptions of possible symptoms, such as front brakes inefficient, to choose from.
APPROPRIATE If the appropriate symptoms indicate problems with the brakes, the computer will instruct the technician to connect one of the seven reels to a test point and which connector to use. With these connections made, dials come up on the screen to display the readings. The computer then asks if the readings are above a certain figure — yes or no; the technician touches the screen to indicate the answer. Soil goes on until the fault is traced and a job card is printed detailing the repair.
A portable engine testing module can be connected via a plug by the fuse board and used during a road test. The system reads two sensors, one around the flywheel and one on the camshaft Readings can be interpreted by the technician or downloaded into the main computer when the full expert diagnostic capability is available.
Systems produced or backed by the manufacturers have the advantage that they are programmed with absolute performance figures. So having done your engine test run the computer will display the results with a good, pass or fail interpretation. If, for instance, the power output of one cylinder is low, the number will be displayed and further investigations can be made. These take the form of inserting a microphone alternately in the oil filler tube, inlet and exhaust manifolds and (Tanking the engine to detect blowby or leaking valves.
Very shortly ABS/ASR diagnostics will be included on Modus as will the standard times for the repairs. When electronic diesel control comes, as it must before 1996, updating will be made through the compact disc read-only memory (CD ROM) system. This is already used for the parts catalogue.
All MAN main dealers have a portable diagnostics system for ABS/ASR and speed limiter systems. It is an expert system and will be updated to cover EDC in the future.
Renault is following the IFT route and is not far behind with its Diagnostica system made by the French diagnostics company Souriau. All Renaults above 3.5 tonnes fitted with any form of electronic control unit (ECU) are being wired to accept Diagnostica. And not only wired, the manifolds are tapped for microphone insertion.
Currently Diagnostica capabilities
include the speed limiter, Airtronic, ABS/ASR,and ACS (automatic clutch system). After plugging in the system, a smart card is inserted to select what area is to be investigated. Again, it is an expert system and is already in all Renault main dealers.
While these systems are the business for the manufacturers' own vehicles they offer no flexibility for other makes — despite the commonality of many ABS. air suspension and speed limiters. This is an area where independent diagnostics and component manufacturers are looking with interest. For instance, Wabcas diagnostic controller will trace faults on its ABS and electronically controlled air suspension system whether fitted to a Renault, Iveco Ford, ERF or any other vehicle.
The Lucas Laser 2000 can be used on its EPIC diesel pumps, as used in the Transit, and its unit diesel injector which is to be used on 12 litre Volvo engines. By changing a small programme cartridge almost any electronic system using an ECU can be interrogated, says Lucas.
The fully independent diagnostics manufacturers are lookIng to offer products that will work on any make of vehicle, much we have seen on the car side. In fact a couf of car systems have distinct CV possibilitit Souriau has just launched its Optima 24'. ABS tester which will operate on Bose Bendix and Teves car based systems. It plugged in between the 35 pin ECU and t' car's wiring loom and uses a smart card match the system under test. Each syste uses the 35 pins for different connections Souriau use a converter board to make t correct connections There are many clever functions on tF device, including the ability to put the vel cle on a rolling road to measure the outp from each wheel sensor individually a; display them all on one screen. The syste can also be used to feed in a speed sigr and then, while the brake pedal is depre.sst it sends a signal which equates to one wiu locking. If the ABS is working correctly should release the brake on that wheel — colleague checks by trying to turn it. In tl way all the valves on the system can checked.
Independently produced diagnostic s3 tems are probably best for non.franchis workshops working on many mak' Movement is expected in this soon with F Cry-pton about to launch a product in die: diagnostics while Souriau is expected announce that its 4080 is to be market through a CV aftermarket specialist.
DETERIORATION At the moment the independently produc diagnostic equipment acts only as a co parator with the new vehicle. It monitors t gradual deterioration and highlights a dramatic change in readings. This situati comes about because the vehicle manuf; turers will not release data to allow prof field checking of their products. In additi some manufacturers refuse to sell their de cared diagnostic equipment to anyone a side their franchised network.
In the USA this situation is under atta from the Freedom of Information Act a environmental legislation. In common w the UK the majority of CVs in the US are s viced outside the franchised network and cannot be checked for compliance with t manufacturer's emission readings. counter this it appears that the legislate may well insist that the data needed check compliance is released to anyone w legitimately requires it.
When similar noises were made in thel they were met with howls of protest fn those with vested interests (most notably 1 car manufacturers).
There are no secrets in ECUs and el tronics wizards can get at all the inforn tion in them — given the financial incenti With that in mind it is only a matter of til before there are as many CV-based diagm, tic systems on the market as there are cars. And the manufacturers' dedicated s tems become as stranded on their sin: marque island as non-franchised worlcshc would be without any diagnostic capabil