What does it mean?
B1500 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Keyless UART Communication Failure . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- Remote key fob will not lock or unlock the vehicle, or works only intermittently
- Passive entry and push button start behave unreliably
- Interior lamps, mirror fold or window functions tied to the remote stop responding
- Alarm arms or disarms at the wrong times, or will not arm at all
- Fault often appears together with other body network complaints
Likely causes
- Failed keyless entry receiver or antenna module
- Open, shorted or high resistance data wire between the receiver and the body control module
- Corroded or partly seated connector at the receiver, often mounted behind trim where moisture collects
- Missing supply or ground to the receiver, so it cannot answer at all
- Body control module input fault or corrupted configuration after a battery or module change
- Aftermarket alarm or remote start spliced into the keyless data line
- Low system voltage causing the receiver to reset during communication
How to fix it
- Confirm the basics first: try a second fob and a fresh fob battery to rule out the transmitter
- Check the receiver fuse, supply voltage and ground before touching the data line
- Inspect the receiver connector for moisture, corrosion and pins that are not fully seated
- Look for aftermarket alarm or remote start splices in the harness and disconnect them for a retest
- Back-probe the data line for activity while operating the fob, and check for continuity and shorts to ground or power
- Repair the harness section between the receiver and the body module
- Replace the receiver first if the wiring is proven good, then the body control module with the required programming