Aftermarket November 2022

BY Frank Massey T his month’s topic has been one of the most rewarding for quite some time, not just on a technical level, but also due to the process and discipline that underlined a smooth progression to a successful ending. It all came about quite by chance, during a random visit to the ADS workshop. Dave Gore, our diagnostic tech called me over to discuss an unusual and thus-far difficult diagnostic challenge. The vehicle in question was a VW Touran V6 3 LTR 2015 model, engine code CVWA. The first unusual aspect of the vehicle was the fitment of a SCR additive system, which theoretically did not enter service until 2016. How very odd. The owner, who we believe was not the original owner, found us online and had the vehicle transported from way down south. The problem first appeared when the vehicle had failed to start while in a car park without any previous issues or warnings that a fault existed. The vehicle would crank and run briefly and it had been to at least two other garages for repair without success or significant progress. Several trim panels had been removed from the dash as well as rear quarter panels. Prior to my involvement, David had conducted some preliminary tests to determine the nature and scale of the problem. This is how I understood the situation; CAN communication errors in the gateway module, most if not all with a common thread, no 20 AFTERMARKET NOVEMBER 2022 TECHNICAL www.aftermarketonline.net LEFT CARRYING THE CAN Process and discipline were the watchwords when Frank recently took on a Volkswagen Touran V6 with a CAN error communication with engine PCM. Comms with transmission and gateway both reported no engine PCM comms. Please refer to Fig.1, which shows gateway errors. Due to a total inability to communicate with the engine PCM, a decision was taken to replace and code a S/H engine PCM, with no change in fault conditions. This was premature in my opinion but that is where we were at this point. David also discovered a vehicle tracker, which he removed. Before I begin with the technical aspects of the journey, it is particularly important for you to understand Even with limited experience or confidence in your diagnostic abilities, your success rate will increase dramatically if you adopt this method ” Right Fig. 1 Fig. 2