2018 Tesla Model 3 engine problems
10 owner complaints filed with NHTSA name the engine on the 2018 Tesla Model 3 — 1% of all complaints for this model year.
What owners report
“High voltage fast charge contactors experienced partial weld failure (BMS_a167_SW_FC_Partial_Weld) during routine Supercharging, causing complete HV system shutdown (hvState = HV_DOWN). Vehicle also threw BMS_a085/a086 Pack and Fast Charge Contactor Mismatch codes. Tesla service is refusing to…”
filed Jun 11, 2026
“Tesla failed to properly diagnose a high-voltage battery isolation fault in my 2018 Model 3. Despite safety-critical BMS_a027 and BMS_a142 faults indicating multiple isolation failures, they skipped required insulation resistance testing, falsely blamed sand in a connector, and charged me $174.95…”
filed Jul 15, 2025
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Engine problems in other Model 3 years
| Year | Reports | Share |
|---|---|---|
| 2025 Model 3 | 3 | 3% |
| 2024 Model 3 | 4 | 2% |
| 2023 Model 3 | 8 | 2% |
| 2022 Model 3 | 7 | 1% |
| 2021 Model 3 | 5 | 1% |
| 2020 Model 3 | 2 | 0% |
| 2019 Model 3 | 2 | 0% |
Other reported problem areas on the 2018 Tesla Model 3
Counts are unique NHTSA complaints naming this component group. Complaints are unverified owner reports; mileage is computed only from complaints that included a usable odometer reading.