Coolant bypass valve failure and engine maintenance warning
ENGINE
127 NHTSA complaints · 2023-06 → 2026-05 (sample of 200 most-recent of 300 total)
“I own a 2020 Toyota Corolla, and without any prior warning, the “Engine Maintenance Required” message appeared on my dashboard at approximately 79,575 miles. There were no unusual symptoms—no overheating, strange noises, or performance issues—before the light turned on. I had…”
“coolant bypass valve is defective and failed prematurely. coolant bypass valve cracks and leaks coolant. Once coolant beings leaking, it comes into contact with the electrical connector located near the valve. The coolant corrodes and damages the connector, which eventually…”
““Engine maintenance required” alert received, related to a faulty coolant bypass valve which will need replacement. Vehicle is currently at 51,049 miles. Alert message can’t be dismissed from the dashboard. It obstructs a significant portion of the speedometer.”
“Just bought a used 20 Corolla SE and put less then 500 miles on it and got a "maintenance required return to dealer" notification on the dash and a warning message in my information screen via infotainment system. Dealer said they got nothing via a scan. The issue is the…”

