What does it mean?
B2426 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Passenger Solar Radiation Sensor Circuit Open .
Symptoms
- Automatic climate control blows too warm on the passenger side in bright sunshine
- Blower speed does not rise as the cabin heats up in the sun
- Dual zone temperature balance feels wrong between the two sides
- Air distribution no longer changes automatically as the sun moves
- The sunload value in the climate menu reads zero or shows dashes
Likely causes
- Open photodiode inside the passenger sunload sensor
- Sensor not seated properly in the dash top after windscreen or trim work
- Broken signal or ground wire in the dash top loom
- Sensor connector unplugged or a terminal backed out of its housing
- Corrosion in the connector following a windscreen or cowl leak
- Open sensor ground shared with other climate control sensors
- Faulty input inside the automatic climate control module
How to fix it
- Read the passenger sunload value in live data and compare it with the driver side sensor under identical light
- Shine a strong light directly on the sensor and watch whether the value responds at all
- Carefully lift the sensor from the dash and confirm the connector is fully seated and free of corrosion
- Measure the reference voltage and the ground at the sensor connector with the ignition on
- Bridge the signal to ground through the specified test resistance and see whether the reported value changes, which proves the wiring
- Check continuity of the signal and ground wires back to the climate control module
- Replace the sensor once the wiring is proven good, then verify both zones respond to a light source