P2228Generic code

P2228 Code: Barometric Pressure Circuit Low

The P2228 code means the barometric pressure (BARO) sensor signal is below its minimum value. The main effect is a less precise mixture and less power, especially at altitude. You can keep driving, but the engine may feel a bit down on power.

Severity
Medium
Can I keep driving?
Yes, no immediate risk
Estimated cost
$40 to $300
Difficulty
Medium
System
Air and Fuel
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P2228 code means

The barometric pressure sensor, which is the circuit the P2228 code monitors, measures atmospheric pressure. The computer uses it to correct the mixture and the turbo for altitude. On many vehicles it sits inside the computer itself, and on others it is in the engine compartment or built into the MAP sensor.

The sensor gets a 5 V reference and a ground from the computer and returns a signal of roughly 0.5 to 4.5 V. A low signal is usually caused by a short to ground on the signal wire or by a missing reference voltage.

At sea level it reads about 100 kPa (14.5 psi), and the pressure drops with altitude. At 2,500 meters (about 8,200 ft) it is around 75 kPa (about 10.9 psi). A sensor guide shows how to test the MAP sensor, which works the same way.

To confirm it, unplug the component with the key on and watch what happens to the reading or the code. If the value jumps to the opposite extreme, the wiring is fine and the component is the one pulling the signal to ground. If nothing changes, look for the short in the wire, starting where the harness rubs against the engine, the chassis or the exhaust.

P2228 code symptoms

  • Check engine light on.
  • Less precise mixture and power, especially at altitude.

Likely causes of the P2228 code

  1. Signal wire shorted to ground where the harness rubs against the engine, the chassis or a bracket.
  2. Shorted power reference. If several sensors fail at the same time, suspect the shared reference.
  3. Damaged sensor with an internal short.
  4. Connector with water or corrosion that creates a path to ground.

How to diagnose the P2228 code step by step

  1. Read the sensor value on the scan tool and compare it with what you expect.
  2. Inspect the connector for corrosion, water or loose pins.
  3. Check power and ground with the key on: correct reference voltage and less than 0.1 V drop on the ground.
  4. Measure the signal with the connector plugged in and see whether it changes with the conditions.
  5. Do a wiggle test on the wiring with the scan tool in graph mode.
  6. Check the continuity of each wire to the computer (less than 1 ohm).

How to fix the P2228 code

  • Repair the connector or the wiring.
  • Replace the sensor if the tests confirm it is bad.
  • Correct the real condition if there is one.
  • Clear the codes and verify with a road test.

After the repair, compare the BARO reading with the MAP reading with the key on and the engine off. If the P2228 code stays away and the two readings agree, the job is done.

Technical reference data

  • At sea level: about 100 kPa (14.5 psi), with a signal near 4 to 4.5 V.
  • The BARO reading and the MAP reading should match with the engine off and the key on.
  • These are reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

On many vehicles the sensor sits inside the computer. In that case rule out everything else before you replace the computer. On turbo diesels it is usually a separate sensor.

P2228 on Toyota

On many Toyota models the sensor is inside the computer, so rule out everything else before replacing it.

P2228 on Honda

On many Honda models the sensor is inside the computer, so rule out everything else before replacing it.

P2228 on Ford

On many Ford models the sensor is inside the computer, so rule out everything else before replacing it.

Frequently asked questions about P2228

Can I drive with a P2228 code?
Yes, with somewhat less performance. The mixture and power are less precise, and you may notice it most at altitude.
Does the sensor have to be replaced?
Only if the tests confirm it. The connector and the wiring fail just as often as the sensor.
What does the barometric pressure sensor do?
It measures atmospheric pressure. The computer uses it to correct the mixture and the turbo for altitude. On many vehicles it is inside the computer, and on others it is in the engine compartment or built into the MAP sensor.
How much does it cost to fix P2228?
Roughly $40 to $300. A wire or connector repair is at the low end, and a new sensor with labor is closer to the top.
What does the P2228 code mean?
It is a generic OBD2 code that means the barometric pressure sensor signal is below its minimum. It usually points to a short to ground or a missing reference voltage.
Will a P2228 code clear itself?
If the short was momentary, the light can go out after several drive cycles. A wire rubbing on metal will bring it back, so find the cause.
What is the most common cause of P2228?
A signal wire shorted to ground where the harness rubs against the engine, chassis or a bracket. A sensor with an internal short is the next most likely.

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