B2100
BodyIgnition Run/Start Input Circuit Performance
On Chrysler, Dodge, Jeep, and similar group models, this code typically relates to a fault in a body electrical system, often a window, door lock, or interior light circuit. The exact interpretation varies by model and which body module is involved.
ⓘ Information only. This page provides general educational information about fault code B2100. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does B2100 mean?
B2100 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Ignition Run/Start Input Circuit Performance.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Specific body system not working: window, central locking, courtesy lights, etc.
- • Sometimes intermittent operation, the system works occasionally then fails
- • Battery drain on some models, the affected circuit may be holding the BCM awake
- • Engine warning light on some integrated systems
- • Multiple body warning indicators flashing or stuck on
Possible causes
Causes commonly associated with B2100, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Failed motor or solenoid in the affected circuit (window motor, door lock actuator, etc.)
- 2. Damaged wiring in the door rubber (where the loom flexes thousands of times) or under the carpet (water damage)
- 3. Connector corroded after years of weather exposure
- 4. Failed body control module (BCM), uncommon but possible after voltage spikes
- 5. Aftermarket modifications: alarms, central locking upgrades, or audio installs that disturbed body wiring
- 6. Water ingress into a connector from a leaking door rubber or screen
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Identify exactly which system isn't working, B2100 is broad but the symptom usually narrows it quickly
- 2. Check fuses for that circuit, free quick check that catches a meaningful share of cases
- 3. Inspect the wiring at the door rubber if the fault is door-related, broken wires inside the rubber concertina are extremely common on older cars
- 4. Test the affected motor or actuator at the connector with a 12V supply, does it operate when given power directly?
- 5. If wiring and components are healthy, the BCM may be the issue; that needs Chrysler-specific diagnostic equipment
Common questions about B2100
Where do I start if multiple things are broken? +
Find the common ground, are all the affected circuits sharing a fuse, a connector, a module, or a ground point? On modern cars with body control modules, multiple unrelated symptoms often point at one BCM fault or one shared connector. Start with what's easiest to inspect (fuses, then visible connectors), then work toward the modules.
Could water ingress have caused this? +
Yes, and it's surprisingly common. Blocked sunroof drains, leaking door rubbers, blocked bulkhead vents, all let water reach the carpet and any connectors under it. If the carpet feels damp, you've found a likely source. Address the leak before fixing the electrical fault, otherwise the repair fails again in months.
Is the car safe to drive? +
Generally yes, but with the affected systems out of action. Don't ignore this if door locks or central locking are involved (security risk) or if the BCM is showing other symptoms (could escalate to no-start). Confirm with a mechanic if uncertain.
Manufacturer-specific notes
Some manufacturers publish additional definitions or variations for this code. Always cross-check with your vehicle's own service documentation.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →