So you are reviewing IATF 16949:2016 and looking for all the specifics on calibration. This article will point you in the right direction.
This revision of the standard is very explicit in referring to ISO 9001:2015 and states clearly:
" This Automotive Quality Management System Standard, herein referred to as "Automotive QMS Standard" or IATF 16949, along with applicable automotive customer-specific requirements, ISO 9001:2015 requirements, and ISO 9000:2015 defines the fundamental quality management system requirements for automotive production and relevant service parts organizations. As such, this Automotive QMS Standard cannot be considered a stand-alone QMS standard but has to be comprehended as a supplement to and used in conjunction with ISO 9001:2015."
That being said, it is expected that your Quality Management System meets ISO 9001:2015 first and then you implement IATF 16949.
IATF 16949 Section 22.214.171.124 Conformance of products and processes.
" The organization shall ensure conformance of all products and processes, including service parts and those that are outsourced, to all applicable customer, statutory and regulatory requirements."
You can't have conformance without calibration and these requirements flow down to suppliers.
Section 126.96.36.199 Measurement Traceability refers to ISO 9001:2015 requirements and includes an informational note.
Note A number or another identifier traceable to the device calibration record meets the intent of the requirements in ISO 9001:2015.
Section 188.8.131.52.1 Calibration/verification records
The organization shall have a documented process for managing calibration/verification records. Records of the calibration.verification activity for all gauges and measuring and test equipment (including employee-owned equipment relevant for measuring, customer-owned equipment, or on-site supplier-owned equipment needed to provide evidence of conformity to internal requirements, legislative and regulatory requirements, and customer-defined requirements shall be retained.
IATF 16949:2016 includes very specific language regarding Internal Calibration activities.
The NOTE above makes it clear that accreditation to ISO 17025 meets the requirements for Internal Laboratory calibrations.
What about External Calibration Laboratories?
The requirement for ISO 17025 accredited calibration is explicitly stated in IATF 16949:2016.
Conclusion: The Automotive Supplier Requirements of IATF 16949:2016 make it clear you should evaluate your calibration program and its conformance to ISO 17025.