VW Golf Leaking Exhaust + Rough Running Diagnosis Help

Had similar issues with my 2013 VW Passat 1.8 TSI. Your symptoms sound exactly like what I experienced, rough idle, exhaust leak, and malfunction indicator. The root cause was a failed Lambda sensor combined with a cracked exhaust pipe near the catalytic converter. The exhaust leak was causing incorrect readings in the NOx sensors, making the engine run rich. This is a serious issue that needs prompt attention as it can damage your catalytic converter if left unchecked. The Lambda sensor failure also affects fuel efficiency and emissions control. The repair involved: Replacing the faulty Lambda sensor, Fixing the exhaust leak at the pipe connection, Clearing the engine codes, Testing the exhaust system for proper operation After the fix, the engine ran smoothly again and the exhaust smell disappeared completely. This type of repair requires proper diagnostic equipment to identify the exact location of the exhaust leak and verify sensor operation. The job took about 4 hours in total. Worth noting that ignoring these symptoms can lead to more expensive repairs down the line, especially if the catalytic converter gets damaged.

Thanks for sharing your experience. The symptoms and repair process you described match what Im going through with my Golf. My particulate filter light also started flashing recently which makes me think its all connected to the exhaust system problems. Did you remember roughly how much you paid for the full repair? Also curious if youve had any other exhaust or DEF fluid related issues since getting it fixed. Im trying to budget for the repairs and want to make sure I address everything at once to avoid multiple garage visits. Would be really helpful to know if the fix held up well or if other problems developed later. The exhaust leak smell is getting worse and Id like to get it sorted before it causes more damage.

Wanted to update you on the repair costs and results. The exhaust treatment malfunction was completely resolved after visiting a certified mechanic. The Lambda sensor replacement came to 375€ including labor and parts. Since the fix three months ago, the car runs perfectly with no exhaust issues or warning lights. The DEF fluid system has been working normally and I havent needed any additional repairs related to the exhaust system. The NOx sensors are now reading correctly and the exhaust pipe isnt showing any signs of leakage. The unpleasant smell is completely gone. Getting it fixed promptly was definitely the right call. The mechanic mentioned that leaving a faulty Lambda sensor unchecked could have led to EGR valve problems and more costly repairs. The particulate filter light you mentioned is likely connected to the same issue I had, so addressing it all at once makes sense. My advice would be to get it checked soon. The total cost was reasonable considering the comprehensive fix and the car performs like new now.

I decided to take my Golf to a specialist VW mechanic based on the helpful advice I received here. Turns out it was exactly what was described, a failed oxygen sensor combined with a cracked section near the catalytic converter that was causing the exhaust leak. The repair bill came to 410€ total, which included: New Lambda/oxygen sensor, Exhaust pipe section repair, Labor costs, System diagnostic check The mechanic completed everything in about 5 hours. The EGR valve and NOx sensors were tested and found to be working correctly. They also checked the particulate filter which needed a forced regeneration cycle. Its been 2 weeks since the repair and the car runs perfectly now. No more rough idle, warning lights or exhaust smells. The fuel economy has improved too. Really glad I got it sorted quickly before it could cause more damage. Thanks again for the advice that helped me understand the issue and get it properly fixed.