2002 Volkswagen Beetle P0507 P0335 P0441 Fault Codes - Low Mileage, Post-Service Issues
I own a 2002 Volkswagen Beetle with a 1.6L engine. After a recent service (described as a 'full' service performed by a National Auto chain rather than a VW dealer), the car began showing warning lights for fault codes P0507 (Throttle Body), P0335 (Crankshaft Position Sensor), and P0441 (Evaporative Emission System). The vehicle had previously run well, with only 18,000 miles on the odometer. Following a service that improved acceleration, these codes appeared. The garage claims they can fix each issue by replacing parts sequentially, estimating a total cost of £1000. However, after clearing the codes, they reappeared immediately. I'm concerned about whether this is due to faulty components or damage caused during the service—especially since the mechanic mentioned difficulty changing spark plugs due to their location. Any insights into possible causes or troubleshooting steps for these specific fault codes in a 2002 Beetle?
What exactly was included in the service prior to the fault codes appearing? Was it a full fluid change, filter replacement, or something else?