VW Passat Hybrid CEL + High Fuel Use Points to VVT Issue

Had similar symptoms with a 2020 VW Arteon Hybrid. The check engine light and high fuel consumption pointed directly to VANOS solenoid problems affecting the variable timing system. After scanning, it turned out one camshaft solenoid valve was failing, causing improper timing and poor engine performance. The engine misfire symptoms got worse over time, especially during cold starts. The root cause was oil sludge buildup in the solenoid, restricting proper operation of the variable timing mechanism. This is a serious issue that needs immediate attention. Continuing to drive with faulty timing control can lead to timing chain damage and potential engine failure. The repair involves replacing the solenoid assembly and performing a thorough oil system cleaning to prevent future sludge accumulation. The job requires specialized diagnostic equipment to properly calibrate the new solenoid with the engine management system. Would strongly recommend finding a shop that specializes in VW hybrids and has experience with variable timing systems. Before replacing parts, have them perform a proper diagnostic to confirm the solenoid is actually failing. Sometimes similar symptoms can be caused by electrical issues in the timing control circuit.

Thanks for the detailed response about VANOS solenoid problems. Your description matches exactly what I experienced with my Passat. The engine misfire and rough idle were quite concerning. Can you recall roughly how much the repair cost you? Also, have you noticed any similar check engine light issues since the fix? Just want to make sure this is a long-term solution and not just a temporary Band-Aid for the variable timing system. Planning to take it to a VW specialist this week, but trying to budget accordingly since these timing-related repairs can get expensive.

Just got the repairs done last week actually. The inlet camshaft solenoid was indeed the problem, causing the variable timing system to malfunction. Total cost came to 250€ to replace the faulty solenoid valve and fix the power supply issue. Since the repair, the check engine light has stayed off and fuel consumption returned to normal. The engine runs much smoother now, especially during cold starts. No more timing-related issues or misfires. Getting it fixed by a proper VW specialist was definitely worth it. They did a full diagnostic scan first to pinpoint the exact problem with the variable timing controls, rather than just blindly replacing parts. They also checked the timing chain and other components while they were in there, all looked good with no signs of oil sludge buildup. From my experience, once the faulty solenoid is replaced and properly calibrated, these issues typically dont come back. Regular oil changes using the correct oil spec will help prevent future variable timing problems.

Thanks for the advice. Finally got my Passat fixed last week and wanted to share my experience. Found a certified VW shop that actually knew what they were doing. The diagnostic confirmed the variable timing problems due to a failing inlet camshaft solenoid. The repair cost came to 280€, slightly more than expected but included a full system cleaning. The low power issues disappeared immediately after the fix and my fuel consumption is back to normal. The mechanic showed me the old solenoid, it was completely gunked up with oil deposits. They recommended switching to a better quality oil and keeping up with regular changes to prevent the check engine light from returning. Really glad I dealt with this promptly instead of risking more engine damage. The car runs like new again and no warning lights since the repair. Thanks again for steering me in the right direction with this VANOS timing issue.