P2BB0: Alternative Fuel Consumption Too Low

What it means

The AFCM detects that alternative fuel consumption falls below the expected value for the active operating mode. Indicates injector clogging, leaks before injectors, or incorrect tank-fill correction.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The alternative fuel control module estimates how much of the alternative fuel is being used in the active operating mode. P2BB0 sets when measured consumption is below the module's expected amount, which can point to restricted alternative-fuel injector flow or an inaccurate tank-fill correction.

Common causes

Most likely first.

1. Alt fuel injectors partially clogged
2. Tank-fill calibration drifted

Symptoms

• Check-engine light
• Reduced power or poor acceleration
• More frequent use of the primary fuel

How to diagnose it

1. Review freeze-frame data and alternative-fuel live data to confirm the code occurred while the engine was operating on that fuel.
2. Check for related alternative-fuel pressure, injector, or switching codes that could explain low measured consumption.
3. Inspect alternative-fuel injector connectors and accessible fuel lines for damage, disconnection, or leakage.
4. Compare commanded injector operation and fuel pressure with the manufacturer's specification while running on alternative fuel.
5. Check the tank-fill correction or calibration data using the vehicle's approved diagnostic procedure.

Common fixes

• Repair a damaged or loose injector connector or fuel line.
• Clean or replace a confirmed restricted alternative-fuel injector.
• Correct tank-fill calibration if testing shows it has drifted.
• Repair a confirmed alternative-fuel pressure or supply fault.

Can I keep driving?

Driving may be possible, but reduced alternative-fuel delivery can cause poor acceleration or a switch to primary fuel. Avoid hard acceleration until the fuel system is checked.