OBD-II Diagnostic Trouble Code
P2229 — Barometric Pressure Sensor A Circuit High
P2229 indicates the barometric pressure sensor A signal voltage is above its expected maximum. An open ground or signal short to voltage on an external sensor, or an internal fault on an ECM-integrated sensor, is likely.
Severity 2/5
Truck-relevant
Service soon
Severity
Service soon
Barometric Pressure Sensor A Circuit High
Code
P2229
Category
Powertrain
Subsystem
Air Flow
Truck-relevant
Yes
What this means for truckers
P2229 (Barometric Pressure Sensor A High) — BARO sensor reading too high. Same fix path.
Before you replace parts — try this first
P2229 on the Air Flow system is most often open sensor ground or signal shorted to reference — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
Check-engine light and possibly a mild derate or altered boost control, as the ECM substitutes a default baro value.
Common causes
- CommonOpen sensor ground or signal shorted to reference ($80–$350)
- CommonFailed barometric sensor ($120–$400)
- OccasionalECM internal sensor fault ($800–$2500)
How to fix
Check the sensor ground and look for a signal short to 5V
When to use: For external sensors
Compare reading to actual atmospheric pressure
When to use: To confirm the fault
Replace sensor or ECM as directed by OEM
When to use: After wiring is verified
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → P229E — NOx Sensor Circuit Bank 1 Sensor 2
- → P229F — NOx Sensor Bank 1 Sensor 2
- → P22A4 — Reductant Heater B Control Circuit/Open
- → P22A5 — Reductant Heater B Control Circuit Low
- → P22A6 — Reductant Heater B Control Circuit High
Frequently Asked Questions
Can I drive with code P2229?
P2229 is severity 2 — service this week. Not an immediate stop, but ignoring it usually compounds the problem. Most common cause for this code is a worn sensor or minor performance fault that won't strand you today but will get more expensive the longer you wait.
How much does it cost to fix P2229 on a commercial truck?
Total repair cost ranges $80–$2500 depending on the root cause. The cheapest fix is usually the first one listed below — Open sensor ground or signal shorted to reference — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will P2229 fail a DOT inspection?
P2229 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between P2229 and related codes?
P2229 is closely related to: P229E (NOx Sensor Circuit Bank 1 Sensor 2), P229F (NOx Sensor Bank 1 Sensor 2), P22A4 (Reductant Heater B Control Circuit/Open), P22A5 (Reductant Heater B Control Circuit Low). These codes share the same subsystem (air-flow) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only P2229 is set without the companions, the issue is more isolated.
How do I prevent P2229 from coming back after a repair?
For P2229 (Barometric Pressure Sensor A Circuit High), prevention centers on the air flow system. Service air filter on time. Clean MAF sensor at every air filter change. Inspect intake boots/hoses for cracks — vibration kills them eventually.