RS4 Timing Chain Issues Causing Power Loss & CEL

My S4 had very similar symptoms at 125000km last year. As someone with basic maintenance experience, this issue initially seemed daunting. The engine light came on during highway driving, accompanied by sluggish acceleration and noticeably higher fuel consumption. The scan showed crankshaft position sensor errors and camshaft timing reference issues. After taking it to a specialist workshop, they diagnosed a faulty crankshaft sensor. The sensor was no longer providing accurate timing data, causing the engine management system to run inefficiently. Total repair cost was 340 Euro including parts and labor. The fix completely resolved the misfire symptoms and restored normal performance. Fuel economy returned to normal levels too. What year is your RS4 and which engine variant? This would help compare if your situation matches what I experienced. Also, have you noticed any unusual sounds from the timing chain area? These details would help determine if your issue is sensor-related or potentially more serious timing component wear. The workshop mentioned these sensors commonly fail around this mileage, but its worth confirming the exact cause for your specific engine variant.

Just had my timing chain tensioner and guides replaced at 192256km due to similar symptoms. The workshop found the cam sensor was giving false readings due to excess chain slack. Fixing the timing components resolved all issues including the engine light and restored proper performance. Labor and parts totaled 2850 Euro. The crank sensor tested fine, confirming it was purely a mechanical timing chain issue. Worth noting the reference value discrepancies completely disappeared after the repair.

Thanks for the update on your RS4 timing chain repair. That matches my experience with the S4 pretty closely. After my initial crank sensor replacement, I ended up having similar timing chain work done at 195000km when the symptoms returned. The slack chain was causing erratic cam sensor readings just like yours. In my case, the total repair included new chain tensioners, guides, and sprockets which ran about 2700 Euro. The timing chain stretch was causing inconsistent readings between the crankshaft and camshaft sensors, leading to those reference value errors we both saw. The workshop mentioned its common for timing components to wear around 190000-200000km on these engines. While my initial sensor replacement provided temporary improvement, addressing the mechanical timing chain wear was the permanent fix needed. Its good to know your repair resolved all the symptoms. The high repair cost is pretty standard when dealing with timing chain components, but its essential maintenance to prevent more serious engine damage.

Thanks for the feedback on the timing chain repairs everyone. After getting my RS4 fixed, I can confirm the initial symptoms pointed to timing chain wear rather than just sensor issues. The engine light, poor performance and high fuel consumption were all related to the stretched chain causing misfire conditions and engine synchronization problems. The 2850 Euro repair bill was significant but necessary to prevent engine damage. Having both the tensioner and guides replaced resolved all timing-related issues. The car now runs perfectly with no more reference errors between the crankshaft and camshaft sensors. For others seeing similar symptoms around 190000km, get the timing components checked even if sensors appear to be the culprit. The slack in the chain system can cause misleading sensor readings and error codes. Its worth the diagnostic time to properly identify worn timing components versus electronic issues. Proper engine timing is now restored and the car performs like new. The repair cost was justified given the critical nature of the timing system and the risk of major engine damage if left unfixed.