I have a 2018 Toyota Highlander with 72k miles. The check-engine light is off but when I scan the computer, it shows a P1605 - Rough Idling error. Anyone know what that is and how to fix it? Not a lot of help online for specific model.
Several possibilities:
Your MAF sensor might be dirty. Clean it. (Simple, cheap to DIY). Or, it could have malfunctioned.
Likewise, the throttle body might be dirty. Clean it. (Simple, cheap to DIY). Or, it could have malfunctioned.
There could be an air intake leak. Scotty has a video (under the faqs, search scotty's videos. He uses a cigar to smoke out any leaks).
How's the engine temperature? Is it reading correctly? If not, there could be a coolant temp sensor malfunction.
From there, it gets more expensive: Fuel pump problems and ECM faults.
Start with the simple and cheap MAF, throttle body cleaning and move up from there, as needed. It's likely to be the easy and cheap, particularly if there hasn't been prior maintenance on the MAF and throttle body.
