Mazda CX-5 2018–2019 — technical service bulletin
Bulletin SA-061-20 · NHTSA communication 10179177 · issued Aug 5, 2020
Technical service bulletin
communication type
Engine and Engine Cooling
component
2018–2019
model years
4
vehicle entries
Official summary
If you receive a customer concern about the CHECK IN light coming on and DTC P3400 (cylinder deactivation system malfunction) stored, perform the inspection in the Repair Procedure.
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.