Virtually all SUVs come with some sort of 4WD system, but when the going gets tough, they don't always get going. That does not apply to the Volkswagen Touareg, however, which will plow its way through the ugliest and most inhospitable conditions you can throw at it. Lots of SUVs claim they can get through the rough stuff; in the case of the Touareg, it's not an idle boast. This is thanks in large measure to VW's 4XMotion all-wheel-drive. Briefly put, this is a permanent all-wheel-drive system that distributes torque between the front and rear driving wheels, depending upon conditions and vehicle load. Not particularly unusual these days, but the Touareg also features a locking centre differential, and, if you ordered it, a locking rear differential as well. Combine this with the traction control system and optional air suspension package, which provides six different ride heights, and you had a mountain goat of an SUV.
The V-6 model was up slightly in displacement over 2006, and was the more popular of the two. It developed 280 horsepower, while the V-8 had 340 hp. Both preferred premium grade fuel and were mated to a six-speed Tiptronic automatic transmission only. Interestingly, they had similar fuel consumption numbers on the highway: 11.0 litres/100 km versus 11.5. Buyers looking for a serious off-road performer, however, would do well to consider the V-8 over the V-6. The latter powerplant was a little on the anemic side, especially with a full load of passengers and luggage. Among other things, the Touareg featured a hill descent and hill ascent setting that automatically engaged low gear when you climbed and kept the vehicle in low when you were descending - in low range. Brakes not required on the way down, in other words. These two features were standard equipment on all models and meant for off-road duty only.
The Touareg has always been a luxury-ute, and standard equipment included dual zone climate control, heated front seats, tire-pressure monitoring system, 17-inch wheels and tires, four-wheel disc brakes with ABS, 60/40-folding rear seat, rear passenger ventilation and one-touch-up/down power windows. Five adults could fit reasonably comfortably, and you could also order "cricket" leather upholstery, an upgraded sound system, the aforementioned air suspension, parking assist, and a heated steering wheel. There was also an optional navi package, heated rear seats, rear window sunshades and 12-way power front seats with upgraded airbags. Just one safety recall to report, and it concerns all Touaregs built from 2007 to 2009. Apparently, the roof-mounted spoiler can work itself loose, possibly fall off the car, and result in all kinds of mayhem. On the other hand, the US National Highway Traffic Safety Administration has at least 34 technical service bulletins on file for this generation of Touareg, and they run the gamut. From transmission "delays" while accelerating, to non-functioning ignition coils, to doors that won't lock, to a wonky fuel delivery system, to the inevitable electrical glitches.
Upload/Download and Extended services are not part of the Automotive Diagnostic Command Set. Diagnostic services have a common message format. Each service defines a Request Message, Positive Response Message, and Negative Response Message. The Request Message has the ServiceId as first byte, plus additional service-defined parameters. The Positive Response Message has an echo of the ServiceId with bit 6 set as first byte, plus the service-defined response parameters. The Negative Response Message is usually a three-byte message: it has the Negative Response ServiceId as first byte, an echo of the original ServiceId as second byte, and a ResponseCode as third byte. The only exception to this format is the negative response to an EscapeCode service; here, the third byte is an echo of the user-defined service code, and the fourth byte is the ResponseCode. The KWP2000 standard partly defines the ResponseCodes, but there is room left for manufacturer-specific extensions. For some of the ResponseCodes, KWP2000 defines an error handling procedure. Because both positive and negative responses have an echo of the requested service, you can always assign the responses to their corresponding request.
KWP2000 expects a diagnostic session to be started with StartDiagnosticSession and terminated with StopDiagnosticSession. However, StartDiagnosticSession has a DiagnosticMode parameter that determines the diagnostic session type. Depending on this type, the ECU may or may not support other diagnostic services, or operate in a restricted mode where not all ECU functions are available. The DiagnosticMode parameter values are manufacturer specific and not defined in the standard. For a diagnostic session to remain active, it must execute the TesterPresent service periodically if no other service is executed. If the TesterPresent service is missing for a certain period of time, the diagnostic session is terminated, and the ECU returns to normal operation mode. A GetSeed/Unlock mechanism may protect some diagnostic services. This defines several levels of security, but the manufacturer assigns these levels to certain services. Use the Read/WriteMemoryByAddress services to upload/download data to certain memory addresses on an ECU. The address is a three-byte quantity in KWP2000 and a five-byte quantity (four-byte address and one-byte extension) in the calibration protocols.
