What causes B1229 on a Honda?

Faulty sunlight sensor Sunlight sensor harness is open or shorted Sunlight sensor circuit poor electrical connection Faulty climate control unit Corroded or loose connector pins at the sensor

How do I fix B1229 on a Honda?

Confirm the code with a scan tool and check the climate control for related faults Inspect the sensor connector for corrosion, moisture, and loose pins Test the sensor signal and reference voltage at the connector Check the wiring for an open or short before replacing the sensor Replace the sunlight sensor if it fails testing, then clear codes and retest

B1229 The climate control unit saw an open in the sunlight sensor circuit

Q: What does B1229 mean on a Honda?

B1229. The climate control unit saw an open in the sunlight sensor circuit. Auto climate may not adjust for sun load and can blow the wrong temperature. Applies to Honda and Acura models that use this code.

Category: Body
Severity: Body Warning Light
Applies to: Honda and Acura models that use this code

What does B1229 mean on a Honda?

B1229. The climate control unit saw an open in the sunlight sensor circuit. Auto climate may not adjust for sun load and can blow the wrong temperature. This Honda-enhanced code applies to Honda and Acura models that use this code.

Common causes of B1229

Faulty sunlight sensor
Sunlight sensor harness is open or shorted
Sunlight sensor circuit poor electrical connection
Faulty climate control unit
Corroded or loose connector pins at the sensor

How to fix B1229

Confirm the code with a scan tool and check the climate control for related faults
Inspect the sensor connector for corrosion, moisture, and loose pins
Test the sensor signal and reference voltage at the connector
Check the wiring for an open or short before replacing the sensor
Replace the sunlight sensor if it fails testing, then clear codes and retest

Sources and review

Last updated 2026-09-29.