What this code means
P2229 may indicate that the ECM/PCM is seeing a barometric pressure signal that is higher than expected.
What the vehicle may do
- The vehicle may turn on the warning light.
- The engine may run normally in some cases.
- Some vehicles can have general drivability or fueling calculation effects.
Possible fault areas
- Possible barometric pressure signal data issue.
- Possible connector or terminal concern.
- Possible PCM software or PCM-related concern.
Diagnostic path
Opening context
On this Accord, P2229 means the ECM/PCM may be seeing a barometric pressure signal that is higher than expected. The vehicle may just have a warning light, it may run normally, or it can show general drivability changes because the ECM/PCM uses that pressure information for engine calculations. Broadly, keep your mind on possible signal data issues, connection concerns, and PCM software or PCM-related checks. Before getting into the test, record the freeze data and any on-board snapshot, and review the basic troubleshooting information so you know when the fault occurred.
Problem verification
Start by turning the ignition switch to ON (II), or press the engine start/stop button to select ON mode. With the HDS, look at the BARO SENSOR parameter. The decision point for this code is whether the BARO SENSOR is more than 4.49 V. If the current reading matches that threshold, the failure is duplicated.
If the fault duplicates
If the BARO SENSOR value is more than 4.49 V, handle it as a current fault. Update the PCM if it does not have the latest software, or substitute a known-good PCM, then move into verification. Keep this as a controlled test path: do not jump into unrelated parts replacement, because this path is centered on PCM software, a known-good PCM comparison, and the follow-up code check.
If the fault does not duplicate
If the BARO SENSOR value does not match the threshold, treat it as an intermittent failure. At that moment, the system is OK. That does not prove the condition never happened; it means the fault is not active under the current test condition, so use the captured data and normal intermittent-fault habits before going any further.
Verify the repair
Keep verification separate from the initial problem check. After the update or known-good PCM step, check for Pending or Confirmed DTCs with the HDS. The question now is simple: is P2229 indicated or not?
Verification results
If P2229 is still indicated, check for poor connections or loose terminals at the PCM. If the PCM was updated, substitute a known-good PCM, then recheck. After a PCM substitution, return to the first problem verification check and repeat the path. If P2229 is not indicated, troubleshooting is complete. If a PCM was substituted during the process, replace the original PCM. If other pending or confirmed codes are present, check what those codes mean and handle their diagnostic paths separately.
Takeaway
The key on P2229 is to verify the BARO SENSOR value first, separate a current fault from an intermittent one, and then prove the result with a clean Pending and Confirmed DTC check. For more diagnostic training, visit stepdiagnostics.com.
Final check
This code is often approached by confirming the sensor signal condition first, then separating an active fault from an intermittent one.
For more guided automotive diagnostics, visit STEP Diagnostics.
