Dear Ask a Mechanic,
On the second page of the owner’s manual for my 2021 Nissan Rogue, it states to not plug in a tracking device or drive monitor into the vehicle’s OBD2 port as it will void the car’s warranty. Insurance companies are promoting theses devices as a way to get lower rates by monitoring driving habits. Are you aware of this restriction being made by other car companies? – Rogue Runner
For readers not familiar with it, the OBD2 port – it stands for on-board diagnostics, level two – is a standard 16-pin electrical connector that’s located inside vehicles, normally in the footwell area on the driver’s side. It is an access point where mechanics can communicate with and diagnose the engine and transmission control modules. It’s been a required part of vehicle emissions equipment since 1996.
In modern vehicles, this data link connector can typically be used by specialized diagnostic equipment to access many of the other vehicle systems that might use the same communication networks.
Because it’s a mandated interface point that must meet a specific Society of Automotive Engineers standard, the data link has a standardized pin configuration. Additionally, the communication protocols used for data transfer are also defined and structured by either the engineering society or the International Organization for Standardization.
All of this is to say that because the data link is mandatory (with very rare exception – certain Tesla models being notable examples), universal by design to allow emission testing and diagnostics, and its operation well-established and strictly defined, it should be a safe place for an interface to read or request data.
While I have not come across a warning of this type in an owner’s manual (or even heard of it), I did experience a situation at an auto event where issues were experienced by several vehicles from different automakers when a third-party fuel-economy tracking device was plugged into their data connectors. I also once diagnosed a defective tracking module that caused major issues in a Chevrolet Cruze. Removing the device corrected the problem and left no apparent aftereffects.
In theory, automotive modules and communication networks are hardened against electrical shorts and other issues. In practice, if such an accessory was to somehow cause damage, and the automaker could prove it was responsible, any possible discount on insurance would suddenly seem moot.
I believe the odds of causing harm are extremely low, however Nissan’s unusual and very specific warning would be enough for me to advise against risking it in your Rogue.
Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to email@example.com. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.
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