P2438 is the bank 2 counterpart of P2433: the secondary air pressure signal of the second bank reads above its upper limit. GM mentions P2438 next to P2437 among the codes that block its AIR sensor and flow tests in the 2018 tables, but publishes no row of its own for it, because the engines described there have one air path. For comparison, GM's bank 1 sensor fails above 94–95 % of the 5 V reference. Typical triggers are a signal shorted to supply voltage, an open ground or an internal sensor defect; Audi's R8 V10, which carries a separate bank 2 sensor G610, shows where such a part sits. No public manufacturer document describes the conditions for P2438 itself. While it is stored, the pump and valve tests cannot be judged.
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 2 is the side without cylinder 1, so it only exists on V or boxer engines.
Symptoms
- Check engine lamp
- Secondary air readiness stays incomplete
Most likely causes
- Signal wire shorted to reference or supply voltage
- Open ground circuit of the bank 2 sensor
- Bank 2 pressure sensor failed internally
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P2438 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 4: Emissions
- 38: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2438?
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 P2438?
The most common causes are: signal wire shorted to reference or supply voltage; open ground circuit of the bank 2 sensor; bank 2 pressure sensor failed internally.
Related codes
- P2433AIR System Air Flow/Pressure Sensor Circuit High (Bank 1)
- P2435AIR System Air Flow/Pressure Sensor Circuit (Bank 2)
- P2437AIR System Air Flow/Pressure Sensor Circuit Low (Bank 2)
- P2439AIR System Air Flow/Pressure Sensor Circuit Intermittent/Erratic (Bank 2)
Sources
- gsi.ext.gm.com: 18OBDG03A Engine Diagnostics
- static.nhtsa.gov: MC 10138306 9999
- law.cornell.edu: 13 CCR 1968.2
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.