Aux Heater Overheat Counter Overrun/System Locked
Your auxiliary heater has overheated so many times that the system has shut itself down to prevent damage, like a circuit breaker flipping after too many electrical surges. The ECU is counting overheat events and has locked the heater out because it exceeded the safe limit.
The ECU monitors auxiliary heater temperature via a thermistor and counts how many times the heater exceeds its safe operating temperature threshold. When the overheat counter reaches a preset limit, the ECU locks out the heater circuit to prevent thermal damage. The system will not re-enable until diagnostics are cleared and conditions normalize.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Heater Temperature | 40–80°C operating range | Exceeds 85°C repeatedly or counter reaches limit |
| Overheat Counter | 0–2 threshold events acceptable | Counter exceeds 3+ events; system locks |
Code B2466 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B2466 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.