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P2440 fault code: what it means

P2440: Secondary air injection switching valve stuck open (cold-start emissions system on some petrol engines).

Engine and gearbox (powertrain) · Minor

Usual causes, most likely first

  1. cracked pressure hose between secondary air pump and combi valve
  2. faulty combi (switching) valve

P2440 by make

Audi

Secondary air injection switching valve stuck open (cold-start emissions system on some petrol engines).

Usual causes: cracked pressure hose between secondary air pump and combi valve; faulty combi (switching) valve

Lexus

Secondary air injection switching valve stuck open (bank 1). Common on LX570 and GX460 V8s; can cause limp mode.

Usual causes: water, ice or debris in the air switching valve; failed secondary air pump; ECM calibration (TSB reflash)

Toyota

Secondary air injection switching valve stuck open (bank 1). Common on V8 Land Cruiser/Tundra/Sequoia (1UR/3UR); can put the engine in limp mode.

Usual causes: water/ice damage to the air switching valve; failed secondary air pump sending debris into the valve; ECM calibration (TSB reflash)

Volkswagen

Secondary air injection switching valve stuck open (cold-start emissions system on some petrol engines).

Usual causes: cracked pressure hose between secondary air pump and combi valve; faulty combi (switching) valve

What the repair usually costs

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Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.