Knock Sensor + Poor Performance: Your Tahoe Warning Signs

Had similar symptoms with my 2020 Chevy Suburban Diesel last winter. The check engine light and rough idle turned out to be exactly what you suspect, a knock sensor malfunction. The main issue wasn't the sensor itself but the wiring harness connection. Moisture had corroded the connector pins, causing intermittent signal problems. The warning light would come on because the engine computer wasn't getting proper input from the sensor, leading to poor fuel efficiency and rough running. The repair involved: Testing sensor circuit continuity, Cleaning connector pins, Replacing damaged wiring section, Recalibrating engine management system It wasn't a serious mechanical problem, but definitely needed fixing to prevent engine damage. Total repair time was about 3 hours. Key questions to ask your mechanic: Will they check wiring before replacing the sensor? Is there a warranty on parts and labor? Do they have diagnostic equipment specific to Duramax diesels? Important: Make sure they check all grounds and connections before swapping parts. Often the sensor itself is fine, it's the electrical connection causing issues.

Thanks for sharing your experience. Had the same issue on my Tahoe, the knock sensor problem was giving me headaches with poor performance and that annoying check engine light. My mechanic also found corroded wiring causing the trouble. How much did you end up paying for the fix? I'm curious if prices have changed since your repair. Also, have you had any other sensor or ignition timing issues pop up since then? My mechanic mentioned these problems sometimes come in pairs, so I'm trying to anticipate what might be next.

Got great news, just wanted to update on the knock sensor repair I mentioned earlier. Turns out it was a straightforward fix, much cheaper than expected at just 95 € for fixing a faulty cable connection. The check engine light disappeared right after the repair, and the poor performance issues cleared up completely. No other sensor problems or engine issues since the fix, the Suburban's running smooth as silk. My fuel efficiency is back to normal too, which is a huge relief given today's fuel prices. The initial warning signs you mentioned about ignition timing issues haven't shown up at all. The key was finding a mechanic who actually tested the wiring before jumping to replace the entire sensor unit. A lot of shops might have pushed for a complete sensor replacement, which would've cost way more. Quick tip: If you're still worried about future problems, have them run a full diagnostic scan. Better to catch any potential issues early while they're checking the electrical system. Most knock sensor problems are actually connection-related rather than sensor failures.

Thanks everyone for the input. Finally got my Tahoe fixed last week and wanted to share how it went. Found a good diesel specialist who took the time to properly diagnose the car problems instead of just throwing parts at it. The mechanic found corroded wiring near the knock sensor connection, just like others mentioned. Total repair came to €275, mostly labor for cleaning connections and replacing a section of damaged wiring. The auto repair only took about 2 hours. Really glad I asked here first, saved me from paying for a complete sensor replacement that wasn't needed. The malfunction indicator light is now off, fuel economy is back to normal, and that annoying engine knock is gone. Mechanic did a full system scan while they were at it and everything else checked out fine. No other sensor issues or problems showing up in the diagnostics. Car's running perfectly now, wish I'd dealt with this sooner instead of letting the poor performance go on for weeks. If anyone else runs into similar symptoms, definitely get the wiring connections checked before replacing sensors. A good diagnostic scan can save a lot of hassle and unnecessary repairs.