I have a 2022 Toyota Highlander with 4k miles, accidentally put 13oz of diesel exhaust fluid (DEF) into the gas tank. I tried to dilute the DEF by filling up with premium gas. About 60 miles of driving the check engine light came on and on the infotainment screen it shows “a malfunction in the electronic control of the engine, throttle, or automatic transmission has been detected. Contact your Toyota dealer to have your vehicle inspected.” Has the engine or the fuel system been damaged? Should I continue to drive it and fill it up with premium gas to burn and get rid of the DEF?
Has the engine or the fuel system been damaged?
Yes. The gas tank should have been immediately drained and fuel system flushed before running the engine. That stuff will cause massive destruction to fuel systems even if mixed with diesel fuel, let alone gasoline.
https://knowhow.napaonline.com/i-accidentally-put-def-fluid-in-a-fuel-tank-now-what/
https://nbcpalmsprings.com/2018/11/19/def-keep-an-eye-on-whats-in-your-gas-tank/
Yep. Having read most of the links @chucktobias posted before answering, you're definitely in for a headache. DEF is ~70% DI water and 30% urea, which is also produced as a waste product in your body and excreted by your kidneys. Urea crystalizes at high temperatures, which will at the very least clog up your fuel injectors, intake valves and exhaust valves. You need to get the fuel system purged ASAP.
I should have added, do not attempt to drive that vehicle any more. Have it towed to a mechanic who can assess the damage.
I tried to dilute the DEF
That was an extremely bad idea. DEF is aqueous urea. Urea solution is very corrosive. It even attacks stainless steel.
The tank should have been emptied and thoroughly cleaned out.
Has the engine or the fuel system been damaged?
The longer you wait , the more damage there will be.
Should I continue to drive it
Absolutely not. It should be towed to a mechanic.
even water (which makes up 68% of DEF) is bad to have in the tank. It'll sink right to the bottom and go right to the engine.