Escalade Turbo Issues Point to Faulty Boost Sensor

I had a very similar issue with my 2020 Cadillac XT6 diesel about 6 months ago. As someone with some basic car maintenance experience, I initially thought it might be a major turbocharger problem, but it turned out to be much simpler. The symptoms you describe, especially the whistling sound and power loss, match what I experienced. The boost sensor was giving incorrect readings due to a loose connection, causing the engine management system to adjust the turbo boost incorrectly. My workshop found that the boost sensor wiring connector had partially worked loose, creating intermittent signal issues. The fix was straightforward, they repaired the cable connection and properly secured the plug, costing 95€ in total. After the repair, the turbo boost returned to normal, and all symptoms disappeared. To help diagnose your specific case, could you share: Any error codes from the engine management system? Does the whistling noise change with engine RPM? Have you noticed if the symptoms are worse in wet weather? Has there been any recent work done near the intake manifold? These details would help determine if your issue matches what I experienced with the boost sensor connection.

Recently completed service at 137765 KM. After checking the error codes with my OBD scanner, I can confirm P0299 and P0234 codes related to the boost sensor and turbocharger operation. The whistling noise definitely increases with RPM, especially noticeable between 2000-3000 RPM. The sound appears to be coming from the air intake area near the turbo system. Thanks for mentioning the boost sensor wiring, I checked and found a small boost leak where the pressure sensor connects to the intake. The connector seems loose and might explain the erratic readings. This discovery definitely aligns with your experience, though I will need a professional to verify if theres additional turbocharger damage.

Thanks for the update and error codes. The P0299 and P0234 codes definitely confirm our suspicions about the boost pressure issues. When I had my Cadillac fixed, the mechanic mentioned these exact codes, which helped pinpoint the turbo boost control system problems. The leak you found at the boost sensor connection is likely the primary culprit, just like in my case. The air intake system needs to maintain specific pressure readings for proper turbo operation. Even a small leak can throw off the sensor readings and cause the engine management system to miscalculate the required turbo boost. Given that your symptoms match my experience so closely, including the RPM-dependent whistling noise, I suggest having the workshop: 1. Check the entire intake manifold for additional leaks 2. Test the boost sensor electrical connections 3. Verify turbo boost pressure readings across different RPM ranges My repair only required fixing the connection and replacing a damaged gasket, total cost was 95€. However, since youve got more mileage on your vehicle, it might be worth having them inspect the turbocharger components while theyre at it. Keep us posted on what the workshop finds. Based on my experience, this should be a straightforward fix without major turbocharger repairs needed.

Thanks everyone for the helpful input. I scheduled an appointment with my local diesel specialist for next week. Ill bring up the boost sensor connection and intake system inspection based on your suggestions. Makes sense that the turbocharger issues could stem from faulty pressure readings due to that loose connection I found. The matching error codes and similar symptoms give me hope this wont require major repairs. Ill keep an eye on the check engine light and try to minimize heavy acceleration until the repair. Will definitely report back with what the mechanic finds, especially if it turns out to be a simple fix like the boost sensor wiring. Really appreciate the detailed diagnostic suggestions, they will help ensure the workshop checks all the right components in the air intake and turbo system. Fingers crossed its just the connection issue and nothing more serious with the turbocharger itself.