Diesel Exhaust Temp Sensor Issues Causing Power Loss?

Had the same headache with my 2020 Tahoe diesel a few months back. The temperature sensor was triggering weird readings, causing the engine to run rich. Got stuck with similar symptoms, check engine light, poor fuel economy, and the engine felt sluggish. Found out there was actually a leak in the exhaust system near the temperature sensor, which was messing with the readings. Shop fixed the leak and replaced the heat sensor, total repair came to 265 for parts and labor. Car's been running perfectly since. What diagnostic codes are you getting? That would help narrow things down. Also, have you noticed any unusual sounds from the exhaust component or visible damage underneath? These temperature fluctuations can sometimes point to different issues depending on where exactly the problem is in the exhaust system. Feel free to share more details about your specific situation, might be able to suggest some more targeted troubleshooting steps.

Thanks for sharing that, making me feel better about my situation. Getting P2033 and P246B codes from my scan tool. The engine management light started flashing about a week ago at 5844 KM. No weird sounds from the exhaust that I can tell, but definitely noticing the power loss and terrible fuel consumption. Checked under the vehicle yesterday and everything looks intact with no visible leaks or damage to the exhaust component. The temperature fluctuation shows up pretty clearly in my OBD readings, jumps all over the place when idling. Think I'll have the shop take a look at that heat sensor first since the symptoms match up pretty closely with what you experienced.

Yeah, those codes definitely point toward emission control issues, similar to what I dealt with. When my temperature readings were jumping around like yours, it turned into a pretty straightforward fix. The heat sensor replacement solved my erratic temperature fluctuation problems completely. My Tahoe's engine management system was getting confused by those bad sensor readings, which explains why we're both seeing that power loss. Had mine fixed around 6000 KM mark, so pretty similar timing to yours. The fact your exhaust system looks intact is actually good news, means you probably won't need the extra repairs I did. Quick heads up though, if you're getting the same issue I had, don't wait too long to fix it. The wonky readings from the sensor can mess with your engine's performance more over time. When they swapped my sensor, fuel consumption went back to normal within a couple of tanks, and the power came right back. The diagnostic readings you're getting match what my scan tool showed before the repair. Those unstable idle temperatures are pretty much identical to what I saw. Since you're not hearing any exhaust leaks, you might get away cheaper than I did, just the sensor swap should do it.

Thanks everyone for the input. Just wanted to update after getting the repair done, turns out you were spot on about the exhaust sensor. Had the shop replace the heat sensor yesterday and the difference is night and day. Power's back to normal, check engine light's gone, and fuel consumption is already looking much better. Total cost came to 220 for the sensor replacement, which wasn't as bad as I feared. The diagnostic codes cleared right up after the fix. Temperature readings are steady now when idling, no more wild fluctuations showing up on the scan tool. Really glad I didn't wait longer to get it fixed. The exhaust component was all good like I thought, just needed that faulty sensor sorted out. Thanks again for helping me pinpoint the problem, saved me from a lot more troubleshooting!