What this code means
B1228 may indicate that the climate control unit is detecting a short in the outside air temperature sensor circuit.
What the vehicle may do
- The outside temperature display may read incorrectly.
- Automatic climate control behavior may seem inaccurate for the actual outside conditions.
- The fault may be intermittent if the code does not return during verification.
Possible fault areas
- Possible wiring or connector problem in the outside air temperature sensor circuit.
- Possible outside air temperature sensor issue.
- Possible climate control unit issue after circuit and sensor checks are completed.
Diagnostic path
Code meaning and diagnostic setup
On this 2010 to 2016 Honda CR-V with the 2.4 gas engine, B1228, also shown as 06 in the climate control self-diagnostic, points to a short in the outside air temperature sensor circuit. In plain terms, the climate control unit may be seeing the outside temperature sensor circuit pulled where it should not be. The driver may notice an outside temperature reading that seems wrong, or automatic climate control behavior that does not quite match actual conditions. Broadly, think possible wiring or connector trouble in the outside air temperature circuit, a possible sensor fault, or a possible climate control unit issue. We are going to prove the fault first, then split the circuit checks in order.
Verify the fault before testing the circuit
Start by clearing the DTC with the HDS. Turn the vehicle to OFF (LOCK), then back to ON. Run the self-diagnostic with the HDS or through the climate control unit, and check for DTCs again. If B1228 or 06 is indicated, keep going into the circuit diagnosis. If it is not indicated, treat it as an intermittent failure and check for loose wires or poor connections in the outside air temperature circuit.
Check the TAM line for a short to ground
Next, turn the vehicle back to OFF (LOCK). Disconnect the climate control unit 32P connector and the outside air temperature sensor 2P connector. With both ends unplugged, check continuity between climate control unit 32P connector No. 19 and body ground. If there is continuity, repair the short to ground in the wire between the climate control unit and the outside air temperature sensor. If there is no continuity, the TAM wire is not shorted to ground, so move to the next check.
Check for a short between TAM and SENSOR COM
Keep the same disconnected setup: vehicle OFF (LOCK), climate control unit 32P connector disconnected, and outside air temperature sensor 2P connector disconnected. Now check continuity between climate control unit 32P connector No. 19 and climate control unit 32P connector No. 23. If there is continuity, repair the short in the wires between the climate control unit and the outside air temperature sensor. If there is no continuity, the TAM wire and SENSOR COM wire are not shorted together, so continue to the sensor check.
Use the sensor result to finish the fault split
Now test the outside air temperature sensor. If the outside air temperature sensor is OK, the diagnostic path points to replacing the climate control unit. If the outside air temperature sensor is not OK, replace the outside air temperature sensor. The key is not to jump to either part until the short-to-ground check and the TAM-to-SENSOR COM short check have both been cleared.
Wrap-up
The clean way through B1228 is simple: verify the code, isolate the TAM circuit from ground, check for a short between TAM and SENSOR COM, then let the outside air temperature sensor test decide the final direction. After the correction, verify the repair and confirm the code stays gone. For more diagnostic training, visit stepdiagnostics.com.
Final check
Verify the code first, then work through the circuit short checks before making the final sensor-versus-control-unit decision.
For more guided automotive diagnostics, visit STEP Diagnostics.
