P2BB0 Alternative Fuel Consumption Too Low
On engines that burn compressed natural gas, LPG or another fuel besides petrol or diesel, the controller can estimate how much gas it has injected and compare that with how fast the tank actually empties, judged by tank pressure or level. P2BB0 means the tank drains noticeably more slowly than the injection quantity implies. That points less to a leak than to wrong bookkeeping: a drifting tank pressure or temperature sensor, injectors or a regulator that deliver less gas than commanded (often with lean codes), or the engine having run on petrol longer than assumed. No manufacturer documents P2BB0 publicly. FCA patented exactly this consumption balance for CNG vehicles, and CARB counts such engines as alternate-fueled vehicles with their own monitoring plans. The opposite case is P2BB1.
Likely causes
Symptoms
- MIL on, sometimes together with lean mixture codes
- Gas range or gauge reading implausible
- Engine switches to petrol more often than usual
Repair estimate
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
Related codes
References: law.cornell.edu, patents.google.com, static.nhtsa.gov.