OBD-II Diagnostic Trouble Code
P2228 — Barometric Pressure Sensor A Circuit Low
P2228 means the barometric pressure sensor A signal voltage is below its expected minimum. On external sensors this usually points to an open signal, a short to ground or lost reference; on ECM-internal sensors it suggests an internal fault.
Severity 2/5
Truck-relevant
Service soon
Severity
Service soon
Barometric Pressure Sensor A Circuit Low
Code
P2228
Category
Powertrain
Subsystem
Air Flow
Truck-relevant
Yes
What this means for truckers
P2228 (Barometric Pressure Sensor A Low) — BARO sensor reading too low. The ECM uses BARO to compensate for altitude. Wrong BARO data affects fuel mixture. Sensor is usually internal to the ECM or in the air intake — replacement varies by truck.
Before you replace parts — try this first
P2228 on the Air Flow system is most often open or grounded signal wire or lost 5v 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, possible reduced power or altered fueling and boost limits because the ECM substitutes a default altitude value.
Common causes
- CommonOpen or grounded signal wire or lost 5V reference ($80–$350)
- CommonFailed barometric sensor ($120–$400)
- OccasionalECM internal sensor fault (where baro is integrated) ($800–$2500)
How to fix
Check 5V reference, ground and signal at an external baro sensor
When to use: When the sensor is external
Check for other 5V sensor codes and isolate a loaded reference
When to use: When multiple sensor codes are present
Replace the sensor or ECM per OEM procedure
When to use: After wiring tests good
Affects most
- RAM 55001 complaint mention this code
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
- → Complaints on RAM 5500
Frequently Asked Questions
Can I drive with code P2228?
P2228 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 P2228 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 or grounded signal wire or lost 5V 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 P2228 fail a DOT inspection?
P2228 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 P2228 and related codes?
P2228 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 P2228 is set without the companions, the issue is more isolated.
How do I prevent P2228 from coming back after a repair?
For P2228 (Barometric Pressure Sensor A Circuit Low), 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.