What this code means
P2229 means the ECM/PCM may be seeing a barometric pressure signal that is higher than expected.
What the vehicle may do
- The vehicle may turn on the check engine light.
- The vehicle can have drivability changes depending on how the ECM/PCM responds.
- The concern may be intermittent.
Possible fault areas
- Possible BARO signal concern as interpreted by the ECM/PCM.
- Possible ECM/PCM connector or terminal issue.
- Possible ECM/PCM software issue.
- Possible ECM/PCM fault.
Diagnostic path
Opening context
On this 2010 to 2015 Honda Civic with the 1.8 gas engine, P2229 points to the BARO sensor circuit reading high voltage. In plain language, the ECM/PCM is seeing a barometric pressure signal that may be higher than expected. The driver may only notice a check engine light, but depending on conditions, the vehicle can have drivability changes because that pressure information is part of the engine control strategy. For this code, keep the possible fault areas broad: the BARO signal as seen by the ECM/PCM, ECM/PCM terminal condition, ECM/PCM software, or the ECM/PCM itself.
Start with captured data
Before troubleshooting, save all freeze data and any on-board snapshot. Then review the basic troubleshooting information and start with a structured approach. That captured data matters here because if the problem is intermittent, you want to know what the vehicle was doing when P2229 set.
Verify the problem on the scan tool
Now turn the ignition switch to ON (II). With the HDS, go into the data list and look at BARO SENSOR. The key decision is whether BARO SENSOR shows about 160 kPa (47.2 inHg, 1,200 mmHg), or 4.49 V or more.
If the high reading is duplicated
If BARO SENSOR is at about 160 kPa (47.2 inHg, 1,200 mmHg), or 4.49 V or more, the failure is duplicated. At that point, update the ECM/PCM if it does not already have the latest software, or substitute a known-good ECM/PCM. After that, move into repair verification.
If the high reading is not present
If BARO SENSOR is not at about 160 kPa (47.2 inHg, 1,200 mmHg), or 4.49 V or more, stop troubleshooting this DTC for now. Treat it as an intermittent failure, with the system OK at this time.
Verify the repair separately
For repair verification, check for Pending or Confirmed DTCs with the HDS and see whether P2229 is still indicated. Keep this verification step separate from the earlier data-list decision. You are no longer trying to prove the high BARO reading; you are confirming whether the code came back.
If P2229 returns during verification
If P2229 is still indicated, check for poor connections or loose terminals at the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then recheck. If the ECM/PCM was already substituted, go back to the beginning of this diagnostic path and work it again from the captured-data step. Do not guess past that point.
If P2229 does not return
If P2229 is not indicated, troubleshooting for this code is complete. If a known-good ECM/PCM was substituted, replace the original ECM/PCM. If any other Pending or Confirmed DTCs are present, handle those by their own diagnostic path.
Closing takeaway
The takeaway on P2229 is simple: prove the BARO value first, act only if the high reading is duplicated, and then verify that P2229 stays gone before calling it fixed. For more diagnostic training, visit stepdiagnostics.com.
Final check
Prove the BARO reading with scan data, follow the ECM/PCM-directed path only when the high reading is duplicated, and verify P2229 does not return.
For more guided automotive diagnostics, visit STEP Diagnostics.
