P029E: Cylinder 2 - Fuel Trim at Max Limit

What it means

Cylinder 2 fuel trim has reached its maximum calibrated limit. The code indicates that the control module cannot apply the required correction; it does not by itself prove the cylinder is structurally lean.

At a glance

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

How it works

The control module monitors fuel correction associated with cylinder 2 to keep combustion within its calibrated range. P029E sets when that correction reaches its maximum limit, indicating the module cannot compensate further; the code alone does not prove cylinder 2 is mechanically lean.

Common causes

Most likely first.

1. Injector restricted or clogged on cylinder 2
2. Air leak affecting cylinder 2
3. Low fuel pressure or delivery problem
4. Cylinder 2 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. Read freeze-frame data, cylinder 2 misfire counts, and fuel-trim or injector data, and check for related air-leak or fuel-pressure codes.
2. Inspect the cylinder 2 intake area for a local air leak and check its injector connector and wiring for damage or poor contact.
3. Compare cylinder 2 fuel correction and injector operation with the other cylinders under the conditions recorded in the freeze frame.
4. Check fuel pressure and delivery against the manufacturer’s specification to identify a supply problem affecting cylinder 2 or the whole engine.
5. Test the cylinder 2 injector and related sensor or control circuits using the manufacturer’s procedure before considering internal engine tests.

Common fixes

• Repair a confirmed air leak affecting cylinder 2.
• Repair damaged or loose cylinder 2 injector wiring or connector.
• Clean or replace a confirmed restricted cylinder 2 injector.
• Repair a fuel-delivery fault if pressure or flow is outside the manufacturer’s specification.

Can I keep driving?

If the engine runs roughly or hesitates, keep trips short and avoid heavy acceleration until cylinder 2’s fuel correction is checked. Prolonged misfiring can damage the catalytic converter and may reduce power further.