VW Up's CEL + Poor MPG Points to Timing System Issues

The symptoms you describe match exactly what happened with my 2014 VW Polo TSI. The check engine light came on and fuel consumption increased dramatically over two weeks. The diagnosis revealed a faulty camshaft solenoid valve in the variable valve timing system. This caused incorrect timing adjustments, leading to low power output and excessive fuel consumption. The solenoid was not engaging properly due to electrical issues in the wiring harness. This is a serious issue that needs immediate attention, as continued driving can potentially cause engine misfire and damage to the timing chain components. My repair required: Complete diagnostic scan, Replacement of camshaft position solenoid, New wiring harness for the timing system, System recalibration The repair took about 6 hours at the shop. Postponing the fix will likely lead to worse problems and potentially leave you stranded. Would strongly recommend finding a shop that specializes in VW engines, particularly ones familiar with variable valve timing systems. Consider getting a second opinion from a certified VW technician who can properly diagnose the exact cause using manufacturer-specific diagnostic tools.

Thanks for sharing your experience with the Polo TSI variable timing issues. What you described sounds exactly like what I am experiencing with my Up. My car is also showing these symptoms and I plan to take it to a specialized VW shop next week. The low power output and high fuel consumption are quite concerning. Did you notice any oil sludge buildup when they opened up the engine to fix the VANOS solenoid? Also curious about the total cost of your repair if you dont mind sharing. Would help me budget for whats coming. Has everything been running smoothly since the repair or have you had any related issues pop up?

Happy to report that since getting the inlet VANOS mechanics fixed, my Polo has been running perfectly with no further issues. The repair centered on a defective camshaft solenoid valve which cost 250€ to replace, including labor. When they opened up the engine, there was actually no oil sludge buildup at all. The issue was purely electrical, a faulty power supply to the solenoid valve was causing the variable timing system to malfunction. This explained the low power and poor fuel economy we both experienced. The engine misfire symptoms and check engine light disappeared immediately after the repair. Fuel consumption returned to normal levels within the first tank of gas. The specialized VW shop did great work diagnosing and fixing the exact problem without any unnecessary parts replacement. Looking back, getting it fixed promptly was definitely the right call to prevent any cascade of timing-related issues. The inlet camshaft is working as designed now with proper variable timing control.

After getting some helpful advice here, I wanted to update everyone on my Up situation. Took it to a specialized VW shop as suggested and the diagnosis confirmed the variable timing problems. The mechanic found similar issues to what others mentioned, a faulty solenoid in the timing system. The repair bill came to 320€ total which included: New camshaft position solenoid, Labor for replacement, System diagnostic and timing reset The work took about 4 hours and the difference is amazing. Check engine light is gone, power is back to normal and fuel economy improved dramatically on the first tank after repair. They showed me the old solenoid which was completely shot, apparently debris had worked its way into the valve. Luckily no engine misfire damage occurred since I caught it relatively early. Really glad I asked here first and found a proper VW specialist. The car runs perfectly now and the repair cost was actually less than I feared. Thanks again for steering me in the right direction with the variable timing system diagnosis.