What does it mean?
B1583 is a Body (airbags, seat belts, body electronics) fault code. It indicates: GPS Signal Unreceived .
Symptoms
- Dash brightness cannot be lowered, or jumps in large steps instead of dimming smoothly
- Illumination flickers whenever the control is touched
- Brightness setting is lost and resets on every key cycle
- Instrument lighting stays uncomfortably bright at night
- On the navigation variant, the vehicle position drifts, freezes or the system reports no satellite reception
Likely causes
- Worn contact track in the dimmer control so the decrease side reads erratically
- Corroded or loose connector at the dimmer control
- Decrease input wire chafed or partly broken behind the dash
- Liquid spilled into the control housing, leaving residue on the contacts
- Unstable reference voltage supplied to the control
- Module input stage degraded
- On applications where this code refers to navigation, a disconnected or damaged GPS antenna, a crushed antenna cable, or the antenna covered by metallic film or aftermarket trim
How to fix it
- Sweep the dimmer control slowly while watching its live value and look for dropouts rather than a single end-to-end reading
- Back-probe the decrease input at the module to confirm the signal is clean and follows the control
- Clean and re-seat the control connector before replacing any part, since contact resistance is a common cause here
- Bench-test the control for continuity through its full travel
- Check the control housing for spilled liquid and corrosion on the contact track
- On the navigation variant, re-seat the antenna connector at the head unit, inspect the cable for crushing under the trim and confirm the antenna has an unobstructed view before replacing it
- Replace the control or the antenna only after wiring and connections have been proven good