P2BB3: Fuel Pump Secondary Circuit Performance

What it means

The ECM detects that the secondary fuel pump control circuit (typically used for high-load enrichment) does not respond as expected. Pump output, relay, or driver fault.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

The secondary fuel pump supplies additional fuel when engine demand rises, such as during high-load operation. The ECM monitors the secondary pump control circuit and its response; P2BB3 sets when that response or pump output does not match what the module expects.

Common causes

Most likely first.

1. Secondary fuel pump relay aged
2. Wiring or connector fault

Symptoms

• Check engine light on
• Hard start, no start, or stalling under load
• Power loss especially at high load or rpm
• Possible long cranking time

How to diagnose it

1. Review freeze-frame data to determine whether the fault occurred during starting, high load, or higher engine speed.
2. Check for related fuel-pressure and pump-control codes that could help separate a supply problem from a circuit problem.
3. Inspect the secondary pump relay, fuse, connector, and wiring for heat damage, corrosion, or loose connections.
4. Use a scan tool to command the secondary pump, if supported, and check whether it operates when requested.
5. Measure the pump circuit and fuel pressure using the manufacturer's procedures to distinguish a relay, wiring, driver, or pump fault.

Common fixes

• Repair a loose or damaged secondary pump connector or wiring.
• Replace a relay that fails testing or has damaged contacts.
• Repair a confirmed fuse or control-circuit fault.
• Replace the secondary fuel pump if it fails an output or pressure test.

Can I keep driving?

Avoid high-load driving, towing, and hard acceleration because the engine may lose power or stall when extra fuel is needed. If it is hard to start or stalls, have it checked before continuing to drive.