What does it mean?
B1307 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Air suspension ECU sensor signal invalid .
Symptoms
- The vehicle sits low at one corner or squats overnight
- Suspension warning message and the system locks into a fixed height
- Ride is harsh or floaty, the compressor may run for unusually long periods
- Automatic levelling and load compensation stop working
- The vehicle may settle onto the bump stops when parked
Likely causes
- Ride height sensor damaged, out of range, or its link arm broken, they sit exposed at the suspension arms
- Height sensor connector corroded or torn loose by road debris and winter salt
- Chafed or stretched wiring at the suspension flex points
- Air spring leaking so the corner drops below the sensor's measuring range
- Compressor or valve block fault preventing the system from reaching a valid height
- Ride height calibration not performed after suspension or sensor work
- Air suspension control module internal fault
How to fix it
- Read all ride height sensor values on a scan tool and compare the four corners against each other
- Measure the actual ride heights with a tape and compare them with the reported values
- Inspect each height sensor, its link arm and its connector for damage, corrosion and looseness
- Wiggle-test the sensor harness while watching live data for dropouts
- Check the air springs and lines for leaks with soapy water and monitor compressor run time
- Replace the faulty height sensor or repair the harness, then carry out the ride height calibration
- Replace the air suspension module only after sensors, wiring and the pneumatic side have all been proven good