OBD-II Code · Body
B1000
ECU Malfunction (Body Control Module)
Severity
high
Left alone, this one tends to take other parts with it.
Can you drive it
Only if running normally
A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety.
Indicative cost (USD)
$400–$1,500
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
Body control module fault.
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 work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
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
- Multiple body electronics issues
- Various warning lights
Likely causes
- Failed BCMMost common
- Wiring
- Moisture damage
Read the full diagnostic procedureB1000 — ECU defective (also seen as ECM internal performance, module internal failure depending on manufacturer) — is one of the few codes where the…
B1000 — ECU defective (also seen as ECM internal performance, module internal failure depending on manufacturer) — is one of the few codes where the module itself is actually the most likely cause, but it is still worth ruling out the cheap stuff first because power, ground, and communication faults can mimic an internal-failure code.
Cheapest first
- clear it, drive, see if it returns immediately or after a delay.
- Check ALL module power feeds with a meter (every fuse the module touches, plus the keyed-on supply), and verify every ground stud and pin is clean and tight — a corroded ground at the inner fender or behind the headlight assembly can cause a module to self-diagnose as defective.
- Watch communication on the CAN/LIN bus with a bidirectional scan tool: if the module shows up in the scanner's module list and responds to ID requests, it is alive enough to be talked to, and an internal-failure code is more credible.
- If it does not show up at all, the fault is more likely wiring or power.
- Voltage at the module's main connector key-on should be within 0.3V of battery, and ground-side voltage drop under load should be under 0.1V. The expensive misdiagnosis: ordering a $400-$1,500 replacement module before checking the $0 power and ground, then finding out the new module sets the same code in 30 seconds because the actual fault was a chewed harness.
Vehicle-specific patterns2003-2007 Ford F-150 — GEM (Generic Electronic Module) sets B1000 after water intrusion at the cowl drain; dry, clean, and seal often recovers.
- 2003-2007Ford F-150 — GEM (Generic Electronic Module) sets B1000 after water intrusion at the cowl drain; dry, clean, and seal often recovers.
- 2005-2010Chrysler 300/Dodge Charger — TIPM (Totally Integrated Power Module) internal failure is a well-documented pattern, often requires TIPM replacement.
- 2007-2012Hyundai/Kia — BCM internal fault after battery jump-start with reversed polarity.
- 2006-2011Honda Civic — driver door multiplex unit fails and sets module-internal codes across the bus.
Estimated repair$0 to $1,800.
Look up another code
B1000 — frequently asked
What does a B1000 code mean?
Body control module fault.
What causes a B1000 code?
Common causes: Failed BCM; Wiring; Moisture damage.
What are the symptoms of a B1000 code?
Typical symptoms: Multiple body electronics issues; Various warning lights.
Is it safe to drive with a B1000 code?
Only if running normally. A short trip to a shop may be reasonable if the light is steady and the car runs normally. Stop safely for a flashing light, severe shaking, overheating, loss of power, or another urgent warning. The code alone cannot confirm safety. Estimated repair: $400-$1,500.
How do I diagnose a B1000 code?
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. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
More free tools