Powertrain, generic (extended)

P2448 AIR System High Air Flow (Bank 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2448 means more secondary air reaches bank 1 than the system expects – for example when the shut-off valve leaks, the pump keeps blowing, or the control logic sees a stronger lean shift than modelled. Ford uses the code: its 2012 OBD summary names P0491, P0410 and P2448 as the bank 1 codes behind the secondary air readiness and in-use monitor counters, and Ford's 2014 code list (published for the Boss 302S) marks P2448 as a MIL code. Ford does not publish a threshold for it. CARB's secondary air rules focus on low flow but demand correct function of the whole system, valves included. Common causes are a valve stuck partly open, an air pump relay that sticks, or a leaking check valve. P0491 is the insufficient-flow counterpart, P2449 covers bank 2.

Likely causes

Shut-off valve does not seal fully
Pump relay sticks, pump runs longer than commanded
Leaking check valve in the air path

Symptoms

  • Check engine lamp
  • Lean-running codes or fuel trim deviation after cold start

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–800
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

secondary air switching valvesecondary air pumpair check valve

Related codes

P2449P0491P0410P2440

References: newtonnet.co.uk, performanceparts.ford.com, law.cornell.edu.