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P codepowertrainMedium severity

P2282Air Leak Between Throttle Body and Intake Valves

Unmetered air is leaking into the engine downstream of the throttle body — a vacuum leak between the throttle plate and the intake valves.

Definition

The PCM compares manifold pressure and airflow against throttle position and idle-control commands; when the engine ingests more air than the closed or nearly closed throttle can explain, it sets P2282 for an air leak between the throttle body and the intake valves. Because this air bypasses both the MAF and the throttle, it leans the mixture most severely at idle. Symptoms include rough or high idle, lean fuel-trim codes, stalling, hesitation, an illuminated MIL, and a potential emissions-test failure.

Common causes

  • Leaking or degraded intake manifold gaskets
  • Cracked or disconnected vacuum hoses off the manifold
  • Brake booster hose or booster diaphragm leak
  • Leaking fuel injector O-rings at the manifold
  • EGR valve or EGR passage gasket leak
  • Cracked plastic intake manifold or leaking manifold runner control seals

Common misdiagnoses

  • Throttle body replaced for an idle problem caused by a manifold leak
  • MAF sensor replaced even though the leak is downstream of it
  • Oxygen sensors replaced for lean readings they are correctly reporting
  • Idle air control or fuel pump replaced chasing idle instability

Troubleshooting steps

  1. 1.Confirm the lean-at-idle signature in fuel trims

    Long-term fuel trim above roughly +10% at idle that improves markedly at 2,500 rpm indicates a fixed-size leak downstream of the throttle.

  2. 2.Smoke-test the intake manifold

    Feed smoke into a manifold vacuum port with the engine off and watch the manifold-to-head joint, hose connections, injector seals, and EGR interface for escaping smoke.

  3. 3.Pinch-test the brake booster hose

    Clamp the booster supply hose at idle; a change in idle speed or trim implicates the booster or its hose, and hissing from the pedal area confirms a diaphragm leak.

  4. 4.Probe suspect joints with propane or carb cleaner

    An rpm or short-term fuel trim change while introducing propane at the manifold gasket line pinpoints the leak location.

  5. 5.Repair, clear codes, and verify

    After replacing the failed gasket or hose, confirm idle trims return to within about ±5% and the code stays clear through a complete drive cycle.

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