P02B2: Cylinder 7 - Fuel Trim at Max Limit

What it means

The control module has reached the maximum fuel-trim correction for cylinder 7. This indicates a cylinder-specific mixture correction limit; the code alone does not identify the underlying cause.

At a glance

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

How it works

The engine computer adjusts fuel for cylinder 7 to keep combustion balanced. This code sets when cylinder 7's fuel-trim correction reaches its upper calibrated limit, which may follow restricted injector flow, extra air at that cylinder, or a fuel delivery or input fault.

Common causes

Most likely first.

1. Injector restricted or clogged on cylinder 7
2. Air leak affecting cylinder 7
3. Low fuel pressure or delivery problem
4. Cylinder 7 sensor, wiring, or control fault

Symptoms

• Check-engine light
• Rough idle or engine vibration
• Misfire or hesitation
• Reduced engine power

How to diagnose it

1. Review freeze-frame data, cylinder-specific fuel-trim values, and misfire counts to see when cylinder 7 reaches its upper limit.
2. Inspect intake passages, vacuum connections, and seals serving cylinder 7 for air leaks.
3. Check cylinder 7 injector connector and wiring for damage, corrosion, or poor contact.
4. Compare cylinder 7 injector flow and contribution with other cylinders using a scan-tool or suitable balance test.
5. Check fuel pressure, cylinder 7 sensor inputs, and injector control against the manufacturer's specification.

Common fixes

• Repair an air leak affecting cylinder 7.
• Clean or replace a restricted cylinder 7 injector based on test results.
• Repair cylinder 7 injector wiring or connections.
• Correct a fuel delivery, sensor, or control fault confirmed by testing.

Can I keep driving?

A short, gentle drive may be possible if the engine runs smoothly; avoid heavy loads and hard acceleration. Stop when safe if it misfires or loses power, because continued misfire can damage the catalytic converter.