Generally, MTTR, MTBF, break down percentage, line stop hours or minutes, etc. are followed as maintenance process indicators and targets.
In general, the parts of the IATF 16949:2016 standard related to the maintenance process; Articles 184.108.40.206, 220.127.116.11, 18.104.22.168,22.214.171.124, and 126.96.36.199.
These topics are plant, production, measurement, etc. periodic maintenance of equipment, predictive maintenance, preventive maintenance, TPM, break down maintenance, cleanliness, repair and contingency actions, and plans to prevent the production and/or delivery to the customer.
In particular, I recommend that you examine these 3 items closely.