B2426

Step 1: Locate the passenger solar radiation sensor (typically mounted on dashboard near windshield on passenger side). Visually inspect the sensor and its connector for physical damage, corrosion, or disconnection. Check for proper seating of connector terminals.

Step 2: Using a digital multimeter, backprobe the sensor connector and measure resistance between sensor ground and signal pins. Compare readings to manufacturer specifications (typically 1-10k ohms depending on temperature/light). Infinite resistance confirms open circuit in sensor.

Step 3: Disconnect sensor and measure continuity of wiring harness from sensor connector to BCM connector using wiring diagram. Check both signal and ground circuits. No continuity confirms open wire; repair or replace harness as needed.

Step 4: If wiring is intact, measure voltage supply at sensor connector with ignition on (typically 5V reference). No voltage indicates BCM issue or power supply problem. Proper voltage with infinite sensor resistance confirms failed sensor.

Step 5: Replace faulty component (sensor, wiring, or connector). Clear codes and verify sensor operation by monitoring live data for proper solar radiation readings that change with light intensity variations.

Step 6: Test drive vehicle and confirm automatic climate control adjusts properly to sunlight conditions. Verify code does not return after multiple drive cycles.