OBD-II Code
B1001
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$75–$600
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
B1001 is a VIN mismatch fault — one or more modules on the vehicle have a VIN programmed into them that does not match the VIN reported by the master controller (usually the BCM or PCM).
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureB1001 is a VIN mismatch fault — one or more modules on the vehicle have a VIN programmed into them that does not match the VIN reported by the master…
B1001 is a VIN mismatch fault — one or more modules on the vehicle have a VIN programmed into them that does not match the VIN reported by the master controller (usually the BCM or PCM). This is almost never a hardware failure; it is a programming/configuration problem, and it sets after module replacement, used-module installation from a salvage yard, theft-recovery reflash situations, or occasionally after a botched dealer reprogramming attempt.
Cheapest first
- read the VIN from every module on the bus with a capable scan tool (this is a free check if you already own one) and identify which module disagrees with the rest — the offending module is almost always one that has been recently replaced.
- The fix is a VIN write/program operation, which on most platforms requires a dealer-level scan tool (Tech 2/MDI/GDS2 for GM, IDS for Ford, wiTECH for FCA) or a competent locksmith/programmer with the right software.
- Some modules are write-once and cannot be re-VINed without a factory tool — these are commonly seen on theft-deterrent and key-immobilizer modules.
- The expensive misdiagnosis: replacing the module a second time, thinking it failed, when the actual fault is just that nobody programmed the VIN into the first replacement; this doubles the parts cost and still does not fix the problem.
Vehicle-specific patterns2004-2013 GM trucks/SUVs — VIN write required on any replacement BCM, ECM, or instrument cluster; Tech 2 or AllData/Mitchell programming required.
- 2004-2013GM trucks/SUVs — VIN write required on any replacement BCM, ECM, or instrument cluster; Tech 2 or AllData/Mitchell programming required.
- 2005-2010Ford F-150 — used PCM from salvage will set B1001 until IDS reflash.
- 2007-2012Chrysler/Dodge/Jeep — TIPM and SKREEM require VIN match; wiTECH dealer tool needed.
- 2008-2014Hyundai/Kia — Smartra immobilizer module is VIN-locked, salvage-yard installs almost always fail.
Estimated repair$75 to $600.
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