B2191: Manufacturer-Specific Body Code (Nissan/Infiniti: Difference of Key / NATS ID Mismatch)
2 vehicles · 2 makes · $600-$1,800 repair
Most Reported On
B2191 is an OBD-II diagnostic trouble code meaning “Manufacturer-Specific Body Code (Nissan/Infiniti: Difference of Key / NATS ID Mismatch).” B2191 is a manufacturer-specific body code. On Nissan and Infiniti vehicles it generally means 'Difference of Key' — the body control module and the NATS Intelligent Key failed ID verification, so the key the system read does not match a registered key. As a security/anti-theft fault, the immobilizer may prevent the engine from starting or the steering lock from releasing. On other makes the meaning could differ, so confirm against the specific service data. This code is most commonly reported on 2008-2013 Nissan Rogue, and 2014-2016 Infiniti QX50, with repair costs ranging from $600 to $1,800.
Common Causes
Typical Repair Cost
Based on 2 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose B2191, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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FAQ
What does B2191 mean?
B2191 stands for "Manufacturer-Specific Body Code (Nissan/Infiniti: Difference of Key / NATS ID Mismatch)." B2191 is a manufacturer-specific body code. On Nissan and Infiniti vehicles it generally means 'Difference of Key' — the body control module and the NATS Intelligent Key failed ID verification, so the key the system read does not match a registered key. As a security/anti-theft fault, the immobilizer may prevent the engine from starting or the steering lock from releasing. On other makes the meaning could differ, so confirm against the specific service data.
What are the most common causes of B2191?
The most common causes of B2191 are: Unregistered or incorrect key/transponder being used, Faulty Intelligent Key or transponder, Wiring fault between key slot/antenna and BCM, Failed key-slot or antenna amplifier, Body control module (BCM/NATS) fault, Interference or low key battery. The specific cause varies by vehicle.
How much does it cost to fix B2191?
Repair costs for B2191 range from $600 to $1,800, depending on the vehicle and root cause.
Which vehicles are affected by B2191?
Au7o has documented B2191 across 2 vehicle models from 2 manufacturers: Infiniti, Nissan.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.