P2431

Code

Generic P — Powertrain

AIR System Air Flow/Pressure Sensor Circuit Range/Performance Bank 1

Brand: Generic

Type: P — Powertrain

Views: UK: 24 EN: 49 RU: 47

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Faulty AIR air flow/pressure sensor (Bank 1)
Open, shorted, corroded or damaged wiring/connector to the sensor
Blocked, restricted or leaking AIR plumbing (hoses, check valve, fittings)
Secondary air pump failure or intermittent operation
Faulty AIR control valve / solenoid or stuck valve
PCM or grounds faulty (less common)

Symptoms

MIL (Check Engine Light) illuminated
Failed emissions test or increased tailpipe emissions
Secondary air pump runs but diagnostic data shows no/low pressure or no change in sensor output
Rough cold idle or extended enrichment during cold start (if AIR system not supplying air)
Audible pump or valve noise if mechanical failure present

What to check

Read freeze frame and live data for AIR flow/pressure sensor values and related AIR system PIDs
Confirm the code is current vs. historic and check readiness/other stored codes
Visually inspect sensor connector and wiring for corrosion, damage, pin push-out, or water entry
Command the secondary air pump and AIR control valve with a scan tool while monitoring the sensor output
Perform a smoke test or visual inspection of AIR hoses, check valve and fittings for leaks, restrictions or collapsed hose
Measure sensor supply voltage, reference ground and signal with a multimeter/oscilloscope.

Signal parameters

Typical sensor signal: 0–5.0 V (varies by manufacturer); expected to change when pump/valve operate (low-to-high or proportional to pressure)
Key‑On/Engine‑Off: sensor may show baseline voltage (often ~0.5–1.0 V) with no AIR pump pressure
With AIR pump active: signal should change smoothly within the sensor’s voltage range; sudden open-circuit (~5 V) or short (~0 V) indicates wiring/sensor fault
Some systems use a frequency or PWM-type output — check factory spec for exact voltage/frequency/pressure map

Diagnostic algorithm

Retrieve and record freeze frame/livedata for AIR sensor and related AIR system PIDs; note when the code set.
Perform visual inspection of the sensor, connector and wiring on Bank 1 for obvious damage, corrosion, rodent chew, or pin issues.
With ignition ON, measure sensor supply voltage (usually 5 V reference) and ground at the connector; confirm presence and good ground.
Back-probe the sensor signal and observe voltage with engine off, then command the AIR pump/valve ON with a scanner or run the pump (as applicable). Verify the sensor voltage changes as expected.
If signal does not change or is out of range, unplug sensor and measure for open/short to power or ground. Repair wiring as needed.
If wiring and connectors are good but signal is still invalid, remove and bench-test or replace the AIR flow/pressure sensor per OE procedure.
Inspect AIR system plumbing: check valve(s), hoses, check valve operation and pump output. Use a pressure gauge or vacuum/pressure source at the sensor port to confirm sensor response.
After repairs, clear codes, perform functional test by commanding pump/valve and confirm sensor behavior returns to specification; road-test as required and verify readiness monitors pass.

Likely causes

Damaged connector or corroded terminals at the sensor
Failed or contaminated air flow/pressure sensor
Blocked hose or failed check valve preventing expected pressure/flow change when pump runs
Intermittent wiring short to ground or power causing out-of-range voltage readings

Fault status

⚠️ Status

P2431 – AIR System Air Flow/Pressure Sensor Circuit Range/Performance (Bank 1): PCM detected sensor output outside expected range or inconsistent with AIR system operation.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours