P2431: AIR System Air Flow/Pressure Sensor Circuit Range/Performance (Bank 1)

P2431 flags a bank 1 secondary air pressure signal that can be read but makes no sense. The usual check compares the sensor with barometric pressure: with the pump off both should agree, with the pump running the rise must stay within limits. GM sets the code on the 3.8L V6 (2005–2006) when the gap exceeds 10 kPa with the pump off or 50 kPa with it on for over 30 s, Type B; the 2018 table works with 15 kPa and 50 kPa. Volkswagen's 2014 Beetle 1.8 TSI allows a deviation of up to 60 hPa from ambient pressure, the Golf CBFA engine only 25 hPa. GM bulletin PIP4409E links P2431 on Colorado, Canyon and H3 to broken MAP sensor wires, because the comparison relies on a correct baro value. Pure circuit faults go under P2432/P2433.

Low severity. Can I keep driving?Yes, you can keep driving, though it should be repaired: the car pollutes more at startup and may not pass an inspection.

Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.

Symptoms

Check engine lamp, often only after cold starts
Secondary air monitor not completed
Possibly further MAP or lean codes if the reference is wrong

Most likely causes

Pressure sensor drifted or reacts too slowly
Wrong barometric reference, e.g. damaged MAP sensor wiring
Restricted or leaking air duct around the sensor port

What to check, in order

Start with the simplest. You can tick off each step.

Listen for the pump running during a cold start
Compare the reading with other engine data while varying the engine speed.
Check the fuse and relay
Inspect the hoses and valve for moisture or carbon
Run the actuator test with the scanner

Good to know

Repair difficulty: medium
It affects emissions.

What each character of P2431 means

P: Powertrain: engine and transmission
2: Generic code: same on every make
4: Emissions
31: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2431?

Yes, you can keep driving, though it should be repaired: the car pollutes more at startup and may not pass an inspection.

What causes code P2431?

The most common causes are: pressure sensor drifted or reacts too slowly; wrong barometric reference, e.g. damaged MAP sensor wiring; restricted or leaking air duct around the sensor port.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.